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