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861 lines
25 KiB
861 lines
25 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* at24.c - handle most I2C EEPROMs |
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* |
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* Copyright (C) 2005-2007 David Brownell |
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* Copyright (C) 2008 Wolfram Sang, Pengutronix |
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*/ |
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|
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#include <linux/acpi.h> |
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#include <linux/bitops.h> |
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#include <linux/capability.h> |
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#include <linux/delay.h> |
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#include <linux/i2c.h> |
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#include <linux/init.h> |
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#include <linux/jiffies.h> |
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#include <linux/kernel.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/nvmem-provider.h> |
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#include <linux/of_device.h> |
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#include <linux/pm_runtime.h> |
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#include <linux/property.h> |
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#include <linux/regmap.h> |
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#include <linux/regulator/consumer.h> |
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#include <linux/slab.h> |
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/* Address pointer is 16 bit. */ |
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#define AT24_FLAG_ADDR16 BIT(7) |
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/* sysfs-entry will be read-only. */ |
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#define AT24_FLAG_READONLY BIT(6) |
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/* sysfs-entry will be world-readable. */ |
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#define AT24_FLAG_IRUGO BIT(5) |
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/* Take always 8 addresses (24c00). */ |
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#define AT24_FLAG_TAKE8ADDR BIT(4) |
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/* Factory-programmed serial number. */ |
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#define AT24_FLAG_SERIAL BIT(3) |
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/* Factory-programmed mac address. */ |
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#define AT24_FLAG_MAC BIT(2) |
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/* Does not auto-rollover reads to the next slave address. */ |
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#define AT24_FLAG_NO_RDROL BIT(1) |
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|
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/* |
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* I2C EEPROMs from most vendors are inexpensive and mostly interchangeable. |
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* Differences between different vendor product lines (like Atmel AT24C or |
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* MicroChip 24LC, etc) won't much matter for typical read/write access. |
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* There are also I2C RAM chips, likewise interchangeable. One example |
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* would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes). |
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* |
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* However, misconfiguration can lose data. "Set 16-bit memory address" |
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* to a part with 8-bit addressing will overwrite data. Writing with too |
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* big a page size also loses data. And it's not safe to assume that the |
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* conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC |
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* uses 0x51, for just one example. |
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* |
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* Accordingly, explicit board-specific configuration data should be used |
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* in almost all cases. (One partial exception is an SMBus used to access |
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* "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.) |
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* |
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* So this driver uses "new style" I2C driver binding, expecting to be |
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* told what devices exist. That may be in arch/X/mach-Y/board-Z.c or |
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* similar kernel-resident tables; or, configuration data coming from |
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* a bootloader. |
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* |
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* Other than binding model, current differences from "eeprom" driver are |
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* that this one handles write access and isn't restricted to 24c02 devices. |
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* It also handles larger devices (32 kbit and up) with two-byte addresses, |
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* which won't work on pure SMBus systems. |
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*/ |
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struct at24_client { |
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struct i2c_client *client; |
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struct regmap *regmap; |
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}; |
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struct at24_data { |
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/* |
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* Lock protects against activities from other Linux tasks, |
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* but not from changes by other I2C masters. |
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*/ |
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struct mutex lock; |
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unsigned int write_max; |
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unsigned int num_addresses; |
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unsigned int offset_adj; |
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u32 byte_len; |
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u16 page_size; |
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u8 flags; |
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struct nvmem_device *nvmem; |
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struct regulator *vcc_reg; |
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void (*read_post)(unsigned int off, char *buf, size_t count); |
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/* |
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* Some chips tie up multiple I2C addresses; dummy devices reserve |
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* them for us, and we'll use them with SMBus calls. |
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*/ |
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struct at24_client client[]; |
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}; |
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/* |
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* This parameter is to help this driver avoid blocking other drivers out |
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* of I2C for potentially troublesome amounts of time. With a 100 kHz I2C |
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* clock, one 256 byte read takes about 1/43 second which is excessive; |
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* but the 1/170 second it takes at 400 kHz may be quite reasonable; and |
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* at 1 MHz (Fm+) a 1/430 second delay could easily be invisible. |
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* |
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* This value is forced to be a power of two so that writes align on pages. |
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*/ |
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static unsigned int at24_io_limit = 128; |
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module_param_named(io_limit, at24_io_limit, uint, 0); |
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MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)"); |
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/* |
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* Specs often allow 5 msec for a page write, sometimes 20 msec; |
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* it's important to recover from write timeouts. |
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*/ |
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static unsigned int at24_write_timeout = 25; |
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module_param_named(write_timeout, at24_write_timeout, uint, 0); |
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MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)"); |
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struct at24_chip_data { |
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u32 byte_len; |
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u8 flags; |
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void (*read_post)(unsigned int off, char *buf, size_t count); |
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}; |
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#define AT24_CHIP_DATA(_name, _len, _flags) \ |
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static const struct at24_chip_data _name = { \ |
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.byte_len = _len, .flags = _flags, \ |
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} |
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#define AT24_CHIP_DATA_CB(_name, _len, _flags, _read_post) \ |
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static const struct at24_chip_data _name = { \ |
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.byte_len = _len, .flags = _flags, \ |
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.read_post = _read_post, \ |
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} |
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static void at24_read_post_vaio(unsigned int off, char *buf, size_t count) |
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{ |
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int i; |
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if (capable(CAP_SYS_ADMIN)) |
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return; |
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/* |
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* Hide VAIO private settings to regular users: |
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* - BIOS passwords: bytes 0x00 to 0x0f |
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* - UUID: bytes 0x10 to 0x1f |
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* - Serial number: 0xc0 to 0xdf |
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*/ |
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for (i = 0; i < count; i++) { |
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if ((off + i <= 0x1f) || |
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(off + i >= 0xc0 && off + i <= 0xdf)) |
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buf[i] = 0; |
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} |
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} |
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/* needs 8 addresses as A0-A2 are ignored */ |
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AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR); |
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/* old variants can't be handled with this generic entry! */ |
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AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0); |
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AT24_CHIP_DATA(at24_data_24cs01, 16, |
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AT24_FLAG_SERIAL | AT24_FLAG_READONLY); |
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AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0); |
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AT24_CHIP_DATA(at24_data_24cs02, 16, |
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AT24_FLAG_SERIAL | AT24_FLAG_READONLY); |
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AT24_CHIP_DATA(at24_data_24mac402, 48 / 8, |
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AT24_FLAG_MAC | AT24_FLAG_READONLY); |
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AT24_CHIP_DATA(at24_data_24mac602, 64 / 8, |
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AT24_FLAG_MAC | AT24_FLAG_READONLY); |
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/* spd is a 24c02 in memory DIMMs */ |
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AT24_CHIP_DATA(at24_data_spd, 2048 / 8, |
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AT24_FLAG_READONLY | AT24_FLAG_IRUGO); |
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/* 24c02_vaio is a 24c02 on some Sony laptops */ |
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AT24_CHIP_DATA_CB(at24_data_24c02_vaio, 2048 / 8, |
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AT24_FLAG_READONLY | AT24_FLAG_IRUGO, |
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at24_read_post_vaio); |
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AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0); |
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AT24_CHIP_DATA(at24_data_24cs04, 16, |
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AT24_FLAG_SERIAL | AT24_FLAG_READONLY); |
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/* 24rf08 quirk is handled at i2c-core */ |
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AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0); |
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AT24_CHIP_DATA(at24_data_24cs08, 16, |
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AT24_FLAG_SERIAL | AT24_FLAG_READONLY); |
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AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0); |
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AT24_CHIP_DATA(at24_data_24cs16, 16, |
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AT24_FLAG_SERIAL | AT24_FLAG_READONLY); |
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AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16); |
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AT24_CHIP_DATA(at24_data_24cs32, 16, |
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AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); |
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AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16); |
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AT24_CHIP_DATA(at24_data_24cs64, 16, |
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AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); |
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AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16); |
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AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16); |
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AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16); |
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AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16); |
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AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16); |
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/* identical to 24c08 ? */ |
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AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0); |
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static const struct i2c_device_id at24_ids[] = { |
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{ "24c00", (kernel_ulong_t)&at24_data_24c00 }, |
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{ "24c01", (kernel_ulong_t)&at24_data_24c01 }, |
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{ "24cs01", (kernel_ulong_t)&at24_data_24cs01 }, |
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{ "24c02", (kernel_ulong_t)&at24_data_24c02 }, |
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{ "24cs02", (kernel_ulong_t)&at24_data_24cs02 }, |
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{ "24mac402", (kernel_ulong_t)&at24_data_24mac402 }, |
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{ "24mac602", (kernel_ulong_t)&at24_data_24mac602 }, |
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{ "spd", (kernel_ulong_t)&at24_data_spd }, |
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{ "24c02-vaio", (kernel_ulong_t)&at24_data_24c02_vaio }, |
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{ "24c04", (kernel_ulong_t)&at24_data_24c04 }, |
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{ "24cs04", (kernel_ulong_t)&at24_data_24cs04 }, |
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{ "24c08", (kernel_ulong_t)&at24_data_24c08 }, |
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{ "24cs08", (kernel_ulong_t)&at24_data_24cs08 }, |
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{ "24c16", (kernel_ulong_t)&at24_data_24c16 }, |
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{ "24cs16", (kernel_ulong_t)&at24_data_24cs16 }, |
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{ "24c32", (kernel_ulong_t)&at24_data_24c32 }, |
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{ "24cs32", (kernel_ulong_t)&at24_data_24cs32 }, |
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{ "24c64", (kernel_ulong_t)&at24_data_24c64 }, |
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{ "24cs64", (kernel_ulong_t)&at24_data_24cs64 }, |
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{ "24c128", (kernel_ulong_t)&at24_data_24c128 }, |
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{ "24c256", (kernel_ulong_t)&at24_data_24c256 }, |
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{ "24c512", (kernel_ulong_t)&at24_data_24c512 }, |
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{ "24c1024", (kernel_ulong_t)&at24_data_24c1024 }, |
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{ "24c2048", (kernel_ulong_t)&at24_data_24c2048 }, |
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{ "at24", 0 }, |
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{ /* END OF LIST */ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, at24_ids); |
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static const struct of_device_id at24_of_match[] = { |
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{ .compatible = "atmel,24c00", .data = &at24_data_24c00 }, |
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{ .compatible = "atmel,24c01", .data = &at24_data_24c01 }, |
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{ .compatible = "atmel,24cs01", .data = &at24_data_24cs01 }, |
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{ .compatible = "atmel,24c02", .data = &at24_data_24c02 }, |
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{ .compatible = "atmel,24cs02", .data = &at24_data_24cs02 }, |
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{ .compatible = "atmel,24mac402", .data = &at24_data_24mac402 }, |
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{ .compatible = "atmel,24mac602", .data = &at24_data_24mac602 }, |
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{ .compatible = "atmel,spd", .data = &at24_data_spd }, |
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{ .compatible = "atmel,24c04", .data = &at24_data_24c04 }, |
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{ .compatible = "atmel,24cs04", .data = &at24_data_24cs04 }, |
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{ .compatible = "atmel,24c08", .data = &at24_data_24c08 }, |
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{ .compatible = "atmel,24cs08", .data = &at24_data_24cs08 }, |
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{ .compatible = "atmel,24c16", .data = &at24_data_24c16 }, |
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{ .compatible = "atmel,24cs16", .data = &at24_data_24cs16 }, |
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{ .compatible = "atmel,24c32", .data = &at24_data_24c32 }, |
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{ .compatible = "atmel,24cs32", .data = &at24_data_24cs32 }, |
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{ .compatible = "atmel,24c64", .data = &at24_data_24c64 }, |
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{ .compatible = "atmel,24cs64", .data = &at24_data_24cs64 }, |
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{ .compatible = "atmel,24c128", .data = &at24_data_24c128 }, |
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{ .compatible = "atmel,24c256", .data = &at24_data_24c256 }, |
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{ .compatible = "atmel,24c512", .data = &at24_data_24c512 }, |
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{ .compatible = "atmel,24c1024", .data = &at24_data_24c1024 }, |
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{ .compatible = "atmel,24c2048", .data = &at24_data_24c2048 }, |
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{ /* END OF LIST */ }, |
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}; |
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MODULE_DEVICE_TABLE(of, at24_of_match); |
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static const struct acpi_device_id __maybe_unused at24_acpi_ids[] = { |
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{ "INT3499", (kernel_ulong_t)&at24_data_INT3499 }, |
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{ "TPF0001", (kernel_ulong_t)&at24_data_24c1024 }, |
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{ /* END OF LIST */ } |
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}; |
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MODULE_DEVICE_TABLE(acpi, at24_acpi_ids); |
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/* |
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* This routine supports chips which consume multiple I2C addresses. It |
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* computes the addressing information to be used for a given r/w request. |
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* Assumes that sanity checks for offset happened at sysfs-layer. |
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* |
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* Slave address and byte offset derive from the offset. Always |
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* set the byte address; on a multi-master board, another master |
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* may have changed the chip's "current" address pointer. |
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*/ |
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static struct at24_client *at24_translate_offset(struct at24_data *at24, |
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unsigned int *offset) |
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{ |
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unsigned int i; |
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if (at24->flags & AT24_FLAG_ADDR16) { |
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i = *offset >> 16; |
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*offset &= 0xffff; |
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} else { |
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i = *offset >> 8; |
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*offset &= 0xff; |
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} |
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return &at24->client[i]; |
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} |
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static struct device *at24_base_client_dev(struct at24_data *at24) |
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{ |
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return &at24->client[0].client->dev; |
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} |
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static size_t at24_adjust_read_count(struct at24_data *at24, |
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unsigned int offset, size_t count) |
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{ |
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unsigned int bits; |
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size_t remainder; |
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/* |
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* In case of multi-address chips that don't rollover reads to |
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* the next slave address: truncate the count to the slave boundary, |
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* so that the read never straddles slaves. |
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*/ |
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if (at24->flags & AT24_FLAG_NO_RDROL) { |
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bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8; |
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remainder = BIT(bits) - offset; |
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if (count > remainder) |
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count = remainder; |
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} |
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if (count > at24_io_limit) |
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count = at24_io_limit; |
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return count; |
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} |
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static ssize_t at24_regmap_read(struct at24_data *at24, char *buf, |
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unsigned int offset, size_t count) |
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{ |
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unsigned long timeout, read_time; |
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struct at24_client *at24_client; |
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struct i2c_client *client; |
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struct regmap *regmap; |
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int ret; |
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at24_client = at24_translate_offset(at24, &offset); |
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regmap = at24_client->regmap; |
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client = at24_client->client; |
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count = at24_adjust_read_count(at24, offset, count); |
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/* adjust offset for mac and serial read ops */ |
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offset += at24->offset_adj; |
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timeout = jiffies + msecs_to_jiffies(at24_write_timeout); |
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do { |
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/* |
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* The timestamp shall be taken before the actual operation |
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* to avoid a premature timeout in case of high CPU load. |
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*/ |
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read_time = jiffies; |
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ret = regmap_bulk_read(regmap, offset, buf, count); |
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dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n", |
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count, offset, ret, jiffies); |
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if (!ret) |
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return count; |
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usleep_range(1000, 1500); |
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} while (time_before(read_time, timeout)); |
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return -ETIMEDOUT; |
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} |
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/* |
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* Note that if the hardware write-protect pin is pulled high, the whole |
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* chip is normally write protected. But there are plenty of product |
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* variants here, including OTP fuses and partial chip protect. |
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* |
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* We only use page mode writes; the alternative is sloooow. These routines |
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* write at most one page. |
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*/ |
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static size_t at24_adjust_write_count(struct at24_data *at24, |
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unsigned int offset, size_t count) |
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{ |
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unsigned int next_page; |
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/* write_max is at most a page */ |
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if (count > at24->write_max) |
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count = at24->write_max; |
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/* Never roll over backwards, to the start of this page */ |
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next_page = roundup(offset + 1, at24->page_size); |
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if (offset + count > next_page) |
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count = next_page - offset; |
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return count; |
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} |
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static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf, |
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unsigned int offset, size_t count) |
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{ |
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unsigned long timeout, write_time; |
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struct at24_client *at24_client; |
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struct i2c_client *client; |
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struct regmap *regmap; |
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int ret; |
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at24_client = at24_translate_offset(at24, &offset); |
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regmap = at24_client->regmap; |
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client = at24_client->client; |
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count = at24_adjust_write_count(at24, offset, count); |
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timeout = jiffies + msecs_to_jiffies(at24_write_timeout); |
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do { |
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/* |
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* The timestamp shall be taken before the actual operation |
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* to avoid a premature timeout in case of high CPU load. |
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*/ |
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write_time = jiffies; |
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ret = regmap_bulk_write(regmap, offset, buf, count); |
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dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n", |
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count, offset, ret, jiffies); |
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if (!ret) |
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return count; |
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usleep_range(1000, 1500); |
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} while (time_before(write_time, timeout)); |
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return -ETIMEDOUT; |
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} |
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static int at24_read(void *priv, unsigned int off, void *val, size_t count) |
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{ |
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struct at24_data *at24; |
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struct device *dev; |
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char *buf = val; |
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int i, ret; |
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at24 = priv; |
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dev = at24_base_client_dev(at24); |
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if (unlikely(!count)) |
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return count; |
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if (off + count > at24->byte_len) |
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return -EINVAL; |
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ret = pm_runtime_get_sync(dev); |
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if (ret < 0) { |
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pm_runtime_put_noidle(dev); |
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return ret; |
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} |
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/* |
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* Read data from chip, protecting against concurrent updates |
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* from this host, but not from other I2C masters. |
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*/ |
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mutex_lock(&at24->lock); |
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for (i = 0; count; i += ret, count -= ret) { |
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ret = at24_regmap_read(at24, buf + i, off + i, count); |
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if (ret < 0) { |
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mutex_unlock(&at24->lock); |
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pm_runtime_put(dev); |
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return ret; |
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} |
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} |
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mutex_unlock(&at24->lock); |
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pm_runtime_put(dev); |
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if (unlikely(at24->read_post)) |
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at24->read_post(off, buf, i); |
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return 0; |
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} |
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static int at24_write(void *priv, unsigned int off, void *val, size_t count) |
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{ |
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struct at24_data *at24; |
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struct device *dev; |
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char *buf = val; |
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int ret; |
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at24 = priv; |
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dev = at24_base_client_dev(at24); |
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if (unlikely(!count)) |
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return -EINVAL; |
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if (off + count > at24->byte_len) |
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return -EINVAL; |
|
|
|
ret = pm_runtime_get_sync(dev); |
|
if (ret < 0) { |
|
pm_runtime_put_noidle(dev); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Write data to chip, protecting against concurrent updates |
|
* from this host, but not from other I2C masters. |
|
*/ |
|
mutex_lock(&at24->lock); |
|
|
|
while (count) { |
|
ret = at24_regmap_write(at24, buf, off, count); |
|
if (ret < 0) { |
|
mutex_unlock(&at24->lock); |
|
pm_runtime_put(dev); |
|
return ret; |
|
} |
|
buf += ret; |
|
off += ret; |
|
count -= ret; |
|
} |
|
|
|
mutex_unlock(&at24->lock); |
|
|
|
pm_runtime_put(dev); |
|
|
|
return 0; |
|
} |
|
|
|
static const struct at24_chip_data *at24_get_chip_data(struct device *dev) |
|
{ |
|
struct device_node *of_node = dev->of_node; |
|
const struct at24_chip_data *cdata; |
|
const struct i2c_device_id *id; |
|
|
|
id = i2c_match_id(at24_ids, to_i2c_client(dev)); |
|
|
|
/* |
|
* The I2C core allows OF nodes compatibles to match against the |
|
* I2C device ID table as a fallback, so check not only if an OF |
|
* node is present but also if it matches an OF device ID entry. |
|
*/ |
|
if (of_node && of_match_device(at24_of_match, dev)) |
|
cdata = of_device_get_match_data(dev); |
|
else if (id) |
|
cdata = (void *)id->driver_data; |
|
else |
|
cdata = acpi_device_get_match_data(dev); |
|
|
|
if (!cdata) |
|
return ERR_PTR(-ENODEV); |
|
|
|
return cdata; |
|
} |
|
|
|
static int at24_make_dummy_client(struct at24_data *at24, unsigned int index, |
|
struct regmap_config *regmap_config) |
|
{ |
|
struct i2c_client *base_client, *dummy_client; |
|
struct regmap *regmap; |
|
struct device *dev; |
|
|
|
base_client = at24->client[0].client; |
|
dev = &base_client->dev; |
|
|
|
dummy_client = devm_i2c_new_dummy_device(dev, base_client->adapter, |
|
base_client->addr + index); |
|
if (IS_ERR(dummy_client)) |
|
return PTR_ERR(dummy_client); |
|
|
|
regmap = devm_regmap_init_i2c(dummy_client, regmap_config); |
|
if (IS_ERR(regmap)) |
|
return PTR_ERR(regmap); |
|
|
|
at24->client[index].client = dummy_client; |
|
at24->client[index].regmap = regmap; |
|
|
|
return 0; |
|
} |
|
|
|
static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len) |
|
{ |
|
if (flags & AT24_FLAG_MAC) { |
|
/* EUI-48 starts from 0x9a, EUI-64 from 0x98 */ |
|
return 0xa0 - byte_len; |
|
} else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) { |
|
/* |
|
* For 16 bit address pointers, the word address must contain |
|
* a '10' sequence in bits 11 and 10 regardless of the |
|
* intended position of the address pointer. |
|
*/ |
|
return 0x0800; |
|
} else if (flags & AT24_FLAG_SERIAL) { |
|
/* |
|
* Otherwise the word address must begin with a '10' sequence, |
|
* regardless of the intended address. |
|
*/ |
|
return 0x0080; |
|
} else { |
|
return 0; |
|
} |
|
} |
|
|
|
static int at24_probe(struct i2c_client *client) |
|
{ |
|
struct regmap_config regmap_config = { }; |
|
struct nvmem_config nvmem_config = { }; |
|
u32 byte_len, page_size, flags, addrw; |
|
const struct at24_chip_data *cdata; |
|
struct device *dev = &client->dev; |
|
bool i2c_fn_i2c, i2c_fn_block; |
|
unsigned int i, num_addresses; |
|
struct at24_data *at24; |
|
struct regmap *regmap; |
|
bool writable; |
|
u8 test_byte; |
|
int err; |
|
|
|
i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C); |
|
i2c_fn_block = i2c_check_functionality(client->adapter, |
|
I2C_FUNC_SMBUS_WRITE_I2C_BLOCK); |
|
|
|
cdata = at24_get_chip_data(dev); |
|
if (IS_ERR(cdata)) |
|
return PTR_ERR(cdata); |
|
|
|
err = device_property_read_u32(dev, "pagesize", &page_size); |
|
if (err) |
|
/* |
|
* This is slow, but we can't know all eeproms, so we better |
|
* play safe. Specifying custom eeprom-types via device tree |
|
* or properties is recommended anyhow. |
|
*/ |
|
page_size = 1; |
|
|
|
flags = cdata->flags; |
|
if (device_property_present(dev, "read-only")) |
|
flags |= AT24_FLAG_READONLY; |
|
if (device_property_present(dev, "no-read-rollover")) |
|
flags |= AT24_FLAG_NO_RDROL; |
|
|
|
err = device_property_read_u32(dev, "address-width", &addrw); |
|
if (!err) { |
|
switch (addrw) { |
|
case 8: |
|
if (flags & AT24_FLAG_ADDR16) |
|
dev_warn(dev, |
|
"Override address width to be 8, while default is 16\n"); |
|
flags &= ~AT24_FLAG_ADDR16; |
|
break; |
|
case 16: |
|
flags |= AT24_FLAG_ADDR16; |
|
break; |
|
default: |
|
dev_warn(dev, "Bad \"address-width\" property: %u\n", |
|
addrw); |
|
} |
|
} |
|
|
|
err = device_property_read_u32(dev, "size", &byte_len); |
|
if (err) |
|
byte_len = cdata->byte_len; |
|
|
|
if (!i2c_fn_i2c && !i2c_fn_block) |
|
page_size = 1; |
|
|
|
if (!page_size) { |
|
dev_err(dev, "page_size must not be 0!\n"); |
|
return -EINVAL; |
|
} |
|
|
|
if (!is_power_of_2(page_size)) |
|
dev_warn(dev, "page_size looks suspicious (no power of 2)!\n"); |
|
|
|
err = device_property_read_u32(dev, "num-addresses", &num_addresses); |
|
if (err) { |
|
if (flags & AT24_FLAG_TAKE8ADDR) |
|
num_addresses = 8; |
|
else |
|
num_addresses = DIV_ROUND_UP(byte_len, |
|
(flags & AT24_FLAG_ADDR16) ? 65536 : 256); |
|
} |
|
|
|
if ((flags & AT24_FLAG_SERIAL) && (flags & AT24_FLAG_MAC)) { |
|
dev_err(dev, |
|
"invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC."); |
|
return -EINVAL; |
|
} |
|
|
|
regmap_config.val_bits = 8; |
|
regmap_config.reg_bits = (flags & AT24_FLAG_ADDR16) ? 16 : 8; |
|
regmap_config.disable_locking = true; |
|
|
|
regmap = devm_regmap_init_i2c(client, ®map_config); |
|
if (IS_ERR(regmap)) |
|
return PTR_ERR(regmap); |
|
|
|
at24 = devm_kzalloc(dev, struct_size(at24, client, num_addresses), |
|
GFP_KERNEL); |
|
if (!at24) |
|
return -ENOMEM; |
|
|
|
mutex_init(&at24->lock); |
|
at24->byte_len = byte_len; |
|
at24->page_size = page_size; |
|
at24->flags = flags; |
|
at24->read_post = cdata->read_post; |
|
at24->num_addresses = num_addresses; |
|
at24->offset_adj = at24_get_offset_adj(flags, byte_len); |
|
at24->client[0].client = client; |
|
at24->client[0].regmap = regmap; |
|
|
|
at24->vcc_reg = devm_regulator_get(dev, "vcc"); |
|
if (IS_ERR(at24->vcc_reg)) |
|
return PTR_ERR(at24->vcc_reg); |
|
|
|
writable = !(flags & AT24_FLAG_READONLY); |
|
if (writable) { |
|
at24->write_max = min_t(unsigned int, |
|
page_size, at24_io_limit); |
|
if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX) |
|
at24->write_max = I2C_SMBUS_BLOCK_MAX; |
|
} |
|
|
|
/* use dummy devices for multiple-address chips */ |
|
for (i = 1; i < num_addresses; i++) { |
|
err = at24_make_dummy_client(at24, i, ®map_config); |
|
if (err) |
|
return err; |
|
} |
|
|
|
/* |
|
* If the 'label' property is not present for the AT24 EEPROM, |
|
* then nvmem_config.id is initialised to NVMEM_DEVID_AUTO, |
|
* and this will append the 'devid' to the name of the NVMEM |
|
* device. This is purely legacy and the AT24 driver has always |
|
* defaulted to this. However, if the 'label' property is |
|
* present then this means that the name is specified by the |
|
* firmware and this name should be used verbatim and so it is |
|
* not necessary to append the 'devid'. |
|
*/ |
|
if (device_property_present(dev, "label")) { |
|
nvmem_config.id = NVMEM_DEVID_NONE; |
|
err = device_property_read_string(dev, "label", |
|
&nvmem_config.name); |
|
if (err) |
|
return err; |
|
} else { |
|
nvmem_config.id = NVMEM_DEVID_AUTO; |
|
nvmem_config.name = dev_name(dev); |
|
} |
|
|
|
nvmem_config.type = NVMEM_TYPE_EEPROM; |
|
nvmem_config.dev = dev; |
|
nvmem_config.read_only = !writable; |
|
nvmem_config.root_only = !(flags & AT24_FLAG_IRUGO); |
|
nvmem_config.owner = THIS_MODULE; |
|
nvmem_config.compat = true; |
|
nvmem_config.base_dev = dev; |
|
nvmem_config.reg_read = at24_read; |
|
nvmem_config.reg_write = at24_write; |
|
nvmem_config.priv = at24; |
|
nvmem_config.stride = 1; |
|
nvmem_config.word_size = 1; |
|
nvmem_config.size = byte_len; |
|
|
|
i2c_set_clientdata(client, at24); |
|
|
|
err = regulator_enable(at24->vcc_reg); |
|
if (err) { |
|
dev_err(dev, "Failed to enable vcc regulator\n"); |
|
return err; |
|
} |
|
|
|
/* enable runtime pm */ |
|
pm_runtime_set_active(dev); |
|
pm_runtime_enable(dev); |
|
|
|
at24->nvmem = devm_nvmem_register(dev, &nvmem_config); |
|
if (IS_ERR(at24->nvmem)) { |
|
pm_runtime_disable(dev); |
|
if (!pm_runtime_status_suspended(dev)) |
|
regulator_disable(at24->vcc_reg); |
|
return PTR_ERR(at24->nvmem); |
|
} |
|
|
|
/* |
|
* Perform a one-byte test read to verify that the |
|
* chip is functional. |
|
*/ |
|
err = at24_read(at24, 0, &test_byte, 1); |
|
if (err) { |
|
pm_runtime_disable(dev); |
|
if (!pm_runtime_status_suspended(dev)) |
|
regulator_disable(at24->vcc_reg); |
|
return -ENODEV; |
|
} |
|
|
|
pm_runtime_idle(dev); |
|
|
|
if (writable) |
|
dev_info(dev, "%u byte %s EEPROM, writable, %u bytes/write\n", |
|
byte_len, client->name, at24->write_max); |
|
else |
|
dev_info(dev, "%u byte %s EEPROM, read-only\n", |
|
byte_len, client->name); |
|
|
|
return 0; |
|
} |
|
|
|
static int at24_remove(struct i2c_client *client) |
|
{ |
|
struct at24_data *at24 = i2c_get_clientdata(client); |
|
|
|
pm_runtime_disable(&client->dev); |
|
if (!pm_runtime_status_suspended(&client->dev)) |
|
regulator_disable(at24->vcc_reg); |
|
pm_runtime_set_suspended(&client->dev); |
|
|
|
return 0; |
|
} |
|
|
|
static int __maybe_unused at24_suspend(struct device *dev) |
|
{ |
|
struct i2c_client *client = to_i2c_client(dev); |
|
struct at24_data *at24 = i2c_get_clientdata(client); |
|
|
|
return regulator_disable(at24->vcc_reg); |
|
} |
|
|
|
static int __maybe_unused at24_resume(struct device *dev) |
|
{ |
|
struct i2c_client *client = to_i2c_client(dev); |
|
struct at24_data *at24 = i2c_get_clientdata(client); |
|
|
|
return regulator_enable(at24->vcc_reg); |
|
} |
|
|
|
static const struct dev_pm_ops at24_pm_ops = { |
|
SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, |
|
pm_runtime_force_resume) |
|
SET_RUNTIME_PM_OPS(at24_suspend, at24_resume, NULL) |
|
}; |
|
|
|
static struct i2c_driver at24_driver = { |
|
.driver = { |
|
.name = "at24", |
|
.pm = &at24_pm_ops, |
|
.of_match_table = at24_of_match, |
|
.acpi_match_table = ACPI_PTR(at24_acpi_ids), |
|
}, |
|
.probe_new = at24_probe, |
|
.remove = at24_remove, |
|
.id_table = at24_ids, |
|
}; |
|
|
|
static int __init at24_init(void) |
|
{ |
|
if (!at24_io_limit) { |
|
pr_err("at24: at24_io_limit must not be 0!\n"); |
|
return -EINVAL; |
|
} |
|
|
|
at24_io_limit = rounddown_pow_of_two(at24_io_limit); |
|
return i2c_add_driver(&at24_driver); |
|
} |
|
module_init(at24_init); |
|
|
|
static void __exit at24_exit(void) |
|
{ |
|
i2c_del_driver(&at24_driver); |
|
} |
|
module_exit(at24_exit); |
|
|
|
MODULE_DESCRIPTION("Driver for most I2C EEPROMs"); |
|
MODULE_AUTHOR("David Brownell and Wolfram Sang"); |
|
MODULE_LICENSE("GPL");
|
|
|