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215 lines
5.6 KiB
215 lines
5.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* I2C driver for stand-alone PCF8584 style adapters on Zorro cards |
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* |
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* Original ICY documentation can be found on Aminet: |
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* https://aminet.net/package/docs/hard/icy |
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* |
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* There has been a modern community re-print of this design in 2019: |
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* https://www.a1k.org/forum/index.php?threads/70106/ |
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* |
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* The card is basically a Philips PCF8584 connected straight to the |
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* beginning of the AutoConfig'd address space (register S1 on base+2), |
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* with /INT on /INT2 on the Zorro bus. |
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* |
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* Copyright (c) 2019 Max Staudt <[email protected]> |
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* |
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* This started as a fork of i2c-elektor.c and has evolved since. |
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* Thanks go to its authors for providing a base to grow on. |
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* |
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* |
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* IRQ support is currently not implemented. |
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* |
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* As it turns out, i2c-algo-pcf is really written with i2c-elektor's |
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* edge-triggered ISA interrupts in mind, while the Amiga's Zorro bus has |
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* level-triggered interrupts. This means that once an interrupt occurs, we |
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* have to tell the PCF8584 to shut up immediately, or it will keep the |
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* interrupt line busy and cause an IRQ storm. |
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* However, because of the PCF8584's host-side protocol, there is no good |
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* way to just quieten it without side effects. Rather, we have to perform |
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* the next read/write operation straight away, which will reset the /INT |
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* pin. This entails re-designing the core of i2c-algo-pcf in the future. |
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* For now, we never request an IRQ from the PCF8584, and poll it instead. |
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*/ |
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#include <linux/delay.h> |
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#include <linux/init.h> |
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#include <linux/io.h> |
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#include <linux/ioport.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/i2c.h> |
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#include <linux/i2c-algo-pcf.h> |
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#include <asm/amigahw.h> |
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#include <asm/amigaints.h> |
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#include <linux/zorro.h> |
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#include "../algos/i2c-algo-pcf.h" |
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struct icy_i2c { |
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struct i2c_adapter adapter; |
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void __iomem *reg_s0; |
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void __iomem *reg_s1; |
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struct i2c_client *ltc2990_client; |
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}; |
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/* |
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* Functions called by i2c-algo-pcf |
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*/ |
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static void icy_pcf_setpcf(void *data, int ctl, int val) |
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{ |
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struct icy_i2c *i2c = (struct icy_i2c *)data; |
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u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0; |
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z_writeb(val, address); |
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} |
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static int icy_pcf_getpcf(void *data, int ctl) |
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{ |
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struct icy_i2c *i2c = (struct icy_i2c *)data; |
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u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0; |
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return z_readb(address); |
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} |
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static int icy_pcf_getown(void *data) |
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{ |
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return 0x55; |
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} |
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static int icy_pcf_getclock(void *data) |
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{ |
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return 0x1c; |
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} |
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static void icy_pcf_waitforpin(void *data) |
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{ |
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usleep_range(50, 150); |
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} |
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/* |
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* Main i2c-icy part |
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*/ |
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static unsigned short const icy_ltc2990_addresses[] = { |
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0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END |
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}; |
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/* |
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* Additional sensors exposed once this property is applied: |
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* |
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* in1 will be the voltage of the 5V rail, divided by 2. |
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* in2 will be the voltage of the 12V rail, divided by 4. |
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* temp3 will be measured using a PCB loop next the chip. |
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*/ |
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static const u32 icy_ltc2990_meas_mode[] = {0, 3}; |
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static const struct property_entry icy_ltc2990_props[] = { |
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PROPERTY_ENTRY_U32_ARRAY("lltc,meas-mode", icy_ltc2990_meas_mode), |
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{ } |
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}; |
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static const struct software_node icy_ltc2990_node = { |
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.properties = icy_ltc2990_props, |
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}; |
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static int icy_probe(struct zorro_dev *z, |
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const struct zorro_device_id *ent) |
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{ |
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struct icy_i2c *i2c; |
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struct i2c_algo_pcf_data *algo_data; |
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struct i2c_board_info ltc2990_info = { |
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.type = "ltc2990", |
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.swnode = &icy_ltc2990_node, |
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}; |
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i2c = devm_kzalloc(&z->dev, sizeof(*i2c), GFP_KERNEL); |
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if (!i2c) |
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return -ENOMEM; |
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algo_data = devm_kzalloc(&z->dev, sizeof(*algo_data), GFP_KERNEL); |
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if (!algo_data) |
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return -ENOMEM; |
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dev_set_drvdata(&z->dev, i2c); |
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i2c->adapter.dev.parent = &z->dev; |
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i2c->adapter.owner = THIS_MODULE; |
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/* i2c->adapter.algo assigned by i2c_pcf_add_bus() */ |
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i2c->adapter.algo_data = algo_data; |
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strlcpy(i2c->adapter.name, "ICY I2C Zorro adapter", |
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sizeof(i2c->adapter.name)); |
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if (!devm_request_mem_region(&z->dev, |
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z->resource.start, |
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4, i2c->adapter.name)) |
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return -ENXIO; |
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/* Driver private data */ |
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i2c->reg_s0 = ZTWO_VADDR(z->resource.start); |
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i2c->reg_s1 = ZTWO_VADDR(z->resource.start + 2); |
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algo_data->data = i2c; |
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algo_data->setpcf = icy_pcf_setpcf; |
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algo_data->getpcf = icy_pcf_getpcf; |
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algo_data->getown = icy_pcf_getown; |
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algo_data->getclock = icy_pcf_getclock; |
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algo_data->waitforpin = icy_pcf_waitforpin; |
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if (i2c_pcf_add_bus(&i2c->adapter)) { |
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dev_err(&z->dev, "i2c_pcf_add_bus() failed\n"); |
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return -ENXIO; |
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} |
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dev_info(&z->dev, "ICY I2C controller at %pa, IRQ not implemented\n", |
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&z->resource.start); |
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/* |
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* The 2019 a1k.org PCBs have an LTC2990 at 0x4c, so start |
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* it automatically once ltc2990 is modprobed. |
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* |
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* in0 is the voltage of the internal 5V power supply. |
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* temp1 is the temperature inside the chip. |
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* |
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* See property_entry above for in1, in2, temp3. |
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*/ |
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i2c->ltc2990_client = i2c_new_scanned_device(&i2c->adapter, |
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<c2990_info, |
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icy_ltc2990_addresses, |
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NULL); |
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return 0; |
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} |
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static void icy_remove(struct zorro_dev *z) |
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{ |
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struct icy_i2c *i2c = dev_get_drvdata(&z->dev); |
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i2c_unregister_device(i2c->ltc2990_client); |
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i2c_del_adapter(&i2c->adapter); |
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} |
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static const struct zorro_device_id icy_zorro_tbl[] = { |
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{ ZORRO_ID(VMC, 15, 0), }, |
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{ 0 } |
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}; |
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MODULE_DEVICE_TABLE(zorro, icy_zorro_tbl); |
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static struct zorro_driver icy_driver = { |
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.name = "i2c-icy", |
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.id_table = icy_zorro_tbl, |
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.probe = icy_probe, |
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.remove = icy_remove, |
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}; |
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module_driver(icy_driver, |
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zorro_register_driver, |
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zorro_unregister_driver); |
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MODULE_AUTHOR("Max Staudt <[email protected]>"); |
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MODULE_DESCRIPTION("I2C bus via PCF8584 on ICY Zorro card"); |
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MODULE_LICENSE("GPL v2");
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