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190 lines
4.7 KiB
190 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Hardware monitoring driver for Maxim MAX15301 |
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* |
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* Copyright (c) 2021 Flextronics International Sweden AB |
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* |
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* Even though the specification does not specifically mention it, |
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* extensive empirical testing has revealed that auto-detection of |
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* limit-registers will fail in a random fashion unless the delay |
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* parameter is set to above about 80us. The default delay is set |
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* to 100us to include some safety margin. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <linux/i2c.h> |
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#include <linux/ktime.h> |
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#include <linux/delay.h> |
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#include <linux/pmbus.h> |
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#include "pmbus.h" |
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static const struct i2c_device_id max15301_id[] = { |
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{"bmr461", 0}, |
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{"max15301", 0}, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(i2c, max15301_id); |
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struct max15301_data { |
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int id; |
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ktime_t access; /* Chip access time */ |
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int delay; /* Delay between chip accesses in us */ |
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struct pmbus_driver_info info; |
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}; |
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#define to_max15301_data(x) container_of(x, struct max15301_data, info) |
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#define MAX15301_WAIT_TIME 100 /* us */ |
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static ushort delay = MAX15301_WAIT_TIME; |
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module_param(delay, ushort, 0644); |
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MODULE_PARM_DESC(delay, "Delay between chip accesses in us"); |
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static struct max15301_data max15301_data = { |
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.info = { |
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.pages = 1, |
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.func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
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| PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
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| PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
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| PMBUS_HAVE_STATUS_TEMP |
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| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT, |
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} |
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}; |
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/* This chip needs a delay between accesses */ |
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static inline void max15301_wait(const struct max15301_data *data) |
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{ |
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if (data->delay) { |
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s64 delta = ktime_us_delta(ktime_get(), data->access); |
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if (delta < data->delay) |
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udelay(data->delay - delta); |
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} |
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} |
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static int max15301_read_word_data(struct i2c_client *client, int page, |
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int phase, int reg) |
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{ |
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client); |
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struct max15301_data *data = to_max15301_data(info); |
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int ret; |
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if (page > 0) |
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return -ENXIO; |
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if (reg >= PMBUS_VIRT_BASE) |
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return -ENXIO; |
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max15301_wait(data); |
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ret = pmbus_read_word_data(client, page, phase, reg); |
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data->access = ktime_get(); |
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return ret; |
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} |
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static int max15301_read_byte_data(struct i2c_client *client, int page, int reg) |
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{ |
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client); |
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struct max15301_data *data = to_max15301_data(info); |
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int ret; |
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if (page > 0) |
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return -ENXIO; |
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max15301_wait(data); |
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ret = pmbus_read_byte_data(client, page, reg); |
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data->access = ktime_get(); |
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return ret; |
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} |
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static int max15301_write_word_data(struct i2c_client *client, int page, int reg, |
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u16 word) |
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{ |
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client); |
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struct max15301_data *data = to_max15301_data(info); |
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int ret; |
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if (page > 0) |
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return -ENXIO; |
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if (reg >= PMBUS_VIRT_BASE) |
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return -ENXIO; |
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max15301_wait(data); |
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ret = pmbus_write_word_data(client, page, reg, word); |
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data->access = ktime_get(); |
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return ret; |
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} |
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static int max15301_write_byte(struct i2c_client *client, int page, u8 value) |
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{ |
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client); |
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struct max15301_data *data = to_max15301_data(info); |
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int ret; |
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if (page > 0) |
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return -ENXIO; |
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max15301_wait(data); |
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ret = pmbus_write_byte(client, page, value); |
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data->access = ktime_get(); |
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return ret; |
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} |
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static int max15301_probe(struct i2c_client *client) |
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{ |
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int status; |
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u8 device_id[I2C_SMBUS_BLOCK_MAX + 1]; |
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const struct i2c_device_id *mid; |
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struct pmbus_driver_info *info = &max15301_data.info; |
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if (!i2c_check_functionality(client->adapter, |
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I2C_FUNC_SMBUS_READ_BYTE_DATA |
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| I2C_FUNC_SMBUS_BLOCK_DATA)) |
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return -ENODEV; |
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status = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, device_id); |
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if (status < 0) { |
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dev_err(&client->dev, "Failed to read Device Id\n"); |
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return status; |
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} |
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for (mid = max15301_id; mid->name[0]; mid++) { |
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if (!strncasecmp(mid->name, device_id, strlen(mid->name))) |
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break; |
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} |
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if (!mid->name[0]) { |
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dev_err(&client->dev, "Unsupported device\n"); |
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return -ENODEV; |
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} |
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max15301_data.delay = delay; |
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info->read_byte_data = max15301_read_byte_data; |
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info->read_word_data = max15301_read_word_data; |
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info->write_byte = max15301_write_byte; |
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info->write_word_data = max15301_write_word_data; |
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return pmbus_do_probe(client, info); |
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} |
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static struct i2c_driver max15301_driver = { |
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.driver = { |
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.name = "max15301", |
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}, |
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.probe_new = max15301_probe, |
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.id_table = max15301_id, |
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}; |
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module_i2c_driver(max15301_driver); |
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MODULE_AUTHOR("Erik Rosen <[email protected]>"); |
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MODULE_DESCRIPTION("PMBus driver for Maxim MAX15301"); |
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MODULE_LICENSE("GPL"); |
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MODULE_IMPORT_NS(PMBUS);
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