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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for MAX20730, MAX20734, and MAX20743 Integrated, Step-Down
* Switching Regulators
*
* Copyright 2019 Google LLC.
*/
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/pmbus.h>
#include <linux/util_macros.h>
#include "pmbus.h"
enum chips {
max20730,
max20734,
max20743
};
struct max20730_data {
enum chips id;
struct pmbus_driver_info info;
struct mutex lock; /* Used to protect against parallel writes */
u16 mfr_devset1;
};
#define to_max20730_data(x) container_of(x, struct max20730_data, info)
#define MAX20730_MFR_DEVSET1 0xd2
/*
* Convert discreet value to direct data format. Strictly speaking, all passed
* values are constants, so we could do that calculation manually. On the
* downside, that would make the driver more difficult to maintain, so lets
* use this approach.
*/
static u16 val_to_direct(int v, enum pmbus_sensor_classes class,
const struct pmbus_driver_info *info)
{
int R = info->R[class] - 3; /* take milli-units into account */
int b = info->b[class] * 1000;
long d;
d = v * info->m[class] + b;
/*
* R < 0 is true for all callers, so we don't need to bother
* about the R > 0 case.
*/
while (R < 0) {
d = DIV_ROUND_CLOSEST(d, 10);
R++;
}
return (u16)d;
}
static long direct_to_val(u16 w, enum pmbus_sensor_classes class,
const struct pmbus_driver_info *info)
{
int R = info->R[class] - 3;
int b = info->b[class] * 1000;
int m = info->m[class];
long d = (s16)w;
if (m == 0)
return 0;
while (R < 0) {
d *= 10;
R++;
}
d = (d - b) / m;
return d;
}
static u32 max_current[][5] = {
[max20730] = { 13000, 16600, 20100, 23600 },
[max20734] = { 21000, 27000, 32000, 38000 },
[max20743] = { 18900, 24100, 29200, 34100 },
};
static int max20730_read_word_data(struct i2c_client *client, int page,
int phase, int reg)
{
const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
const struct max20730_data *data = to_max20730_data(info);
int ret = 0;
u32 max_c;
switch (reg) {
case PMBUS_OT_FAULT_LIMIT:
switch ((data->mfr_devset1 >> 11) & 0x3) {
case 0x0:
ret = val_to_direct(150000, PSC_TEMPERATURE, info);
break;
case 0x1:
ret = val_to_direct(130000, PSC_TEMPERATURE, info);
break;
default:
ret = -ENODATA;
break;
}
break;
case PMBUS_IOUT_OC_FAULT_LIMIT:
max_c = max_current[data->id][(data->mfr_devset1 >> 5) & 0x3];
ret = val_to_direct(max_c, PSC_CURRENT_OUT, info);
break;
default:
ret = -ENODATA;
break;
}
return ret;
}
static int max20730_write_word_data(struct i2c_client *client, int page,
int reg, u16 word)
{
struct pmbus_driver_info *info;
struct max20730_data *data;
u16 devset1;
int ret = 0;
int idx;
info = (struct pmbus_driver_info *)pmbus_get_driver_info(client);
data = to_max20730_data(info);
mutex_lock(&data->lock);
devset1 = data->mfr_devset1;
switch (reg) {
case PMBUS_OT_FAULT_LIMIT:
devset1 &= ~(BIT(11) | BIT(12));
if (direct_to_val(word, PSC_TEMPERATURE, info) < 140000)
devset1 |= BIT(11);
break;
case PMBUS_IOUT_OC_FAULT_LIMIT:
devset1 &= ~(BIT(5) | BIT(6));
idx = find_closest(direct_to_val(word, PSC_CURRENT_OUT, info),
max_current[data->id], 4);
devset1 |= (idx << 5);
break;
default:
ret = -ENODATA;
break;
}
if (!ret && devset1 != data->mfr_devset1) {
ret = i2c_smbus_write_word_data(client, MAX20730_MFR_DEVSET1,
devset1);
if (!ret) {
data->mfr_devset1 = devset1;
pmbus_clear_cache(client);
}
}
mutex_unlock(&data->lock);
return ret;
}
static const struct pmbus_driver_info max20730_info[] = {
[max20730] = {
.pages = 1,
.read_word_data = max20730_read_word_data,
.write_word_data = max20730_write_word_data,
/* Source : Maxim AN6042 */
.format[PSC_TEMPERATURE] = direct,
.m[PSC_TEMPERATURE] = 21,
.b[PSC_TEMPERATURE] = 5887,
.R[PSC_TEMPERATURE] = -1,
.format[PSC_VOLTAGE_IN] = direct,
.m[PSC_VOLTAGE_IN] = 3609,
.b[PSC_VOLTAGE_IN] = 0,
.R[PSC_VOLTAGE_IN] = -2,
/*
* Values in the datasheet are adjusted for temperature and
* for the relationship between Vin and Vout.
* Unfortunately, the data sheet suggests that Vout measurement
* may be scaled with a resistor array. This is indeed the case
* at least on the evaulation boards. As a result, any in-driver
* adjustments would either be wrong or require elaborate means
* to configure the scaling. Instead of doing that, just report
* raw values and let userspace handle adjustments.
*/
.format[PSC_CURRENT_OUT] = direct,
.m[PSC_CURRENT_OUT] = 153,
.b[PSC_CURRENT_OUT] = 4976,
.R[PSC_CURRENT_OUT] = -1,
.format[PSC_VOLTAGE_OUT] = linear,
.func[0] = PMBUS_HAVE_VIN |
PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
},
[max20734] = {
.pages = 1,
.read_word_data = max20730_read_word_data,
.write_word_data = max20730_write_word_data,
/* Source : Maxim AN6209 */
.format[PSC_TEMPERATURE] = direct,
.m[PSC_TEMPERATURE] = 21,
.b[PSC_TEMPERATURE] = 5887,
.R[PSC_TEMPERATURE] = -1,
.format[PSC_VOLTAGE_IN] = direct,
.m[PSC_VOLTAGE_IN] = 3592,
.b[PSC_VOLTAGE_IN] = 0,
.R[PSC_VOLTAGE_IN] = -2,
.format[PSC_CURRENT_OUT] = direct,
.m[PSC_CURRENT_OUT] = 111,
.b[PSC_CURRENT_OUT] = 3461,
.R[PSC_CURRENT_OUT] = -1,
.format[PSC_VOLTAGE_OUT] = linear,
.func[0] = PMBUS_HAVE_VIN |
PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
},
[max20743] = {
.pages = 1,
.read_word_data = max20730_read_word_data,
.write_word_data = max20730_write_word_data,
/* Source : Maxim AN6042 */
.format[PSC_TEMPERATURE] = direct,
.m[PSC_TEMPERATURE] = 21,
.b[PSC_TEMPERATURE] = 5887,
.R[PSC_TEMPERATURE] = -1,
.format[PSC_VOLTAGE_IN] = direct,
.m[PSC_VOLTAGE_IN] = 3597,
.b[PSC_VOLTAGE_IN] = 0,
.R[PSC_VOLTAGE_IN] = -2,
.format[PSC_CURRENT_OUT] = direct,
.m[PSC_CURRENT_OUT] = 95,
.b[PSC_CURRENT_OUT] = 5014,
.R[PSC_CURRENT_OUT] = -1,
.format[PSC_VOLTAGE_OUT] = linear,
.func[0] = PMBUS_HAVE_VIN |
PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
},
};
static int max20730_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
struct max20730_data *data;
enum chips chip_id;
int ret;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_BYTE_DATA |
I2C_FUNC_SMBUS_READ_WORD_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA))
return -ENODEV;
ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
if (ret < 0) {
dev_err(&client->dev, "Failed to read Manufacturer ID\n");
return ret;
}
if (ret != 5 || strncmp(buf, "MAXIM", 5)) {
buf[ret] = '\0';
dev_err(dev, "Unsupported Manufacturer ID '%s'\n", buf);
return -ENODEV;
}
/*
* The chips support reading PMBUS_MFR_MODEL. On both MAX20730
* and MAX20734, reading it returns M20743. Presumably that is
* the reason why the command is not documented. Unfortunately,
* that means that there is no reliable means to detect the chip.
* However, we can at least detect the chip series. Compare
* the returned value against 'M20743' and bail out if there is
* a mismatch. If that doesn't work for all chips, we may have
* to remove this check.
*/
ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
if (ret < 0) {
dev_err(dev, "Failed to read Manufacturer Model\n");
return ret;
}
if (ret != 6 || strncmp(buf, "M20743", 6)) {
buf[ret] = '\0';
dev_err(dev, "Unsupported Manufacturer Model '%s'\n", buf);
return -ENODEV;
}
ret = i2c_smbus_read_block_data(client, PMBUS_MFR_REVISION, buf);
if (ret < 0) {
dev_err(dev, "Failed to read Manufacturer Revision\n");
return ret;
}
if (ret != 1 || buf[0] != 'F') {
buf[ret] = '\0';
dev_err(dev, "Unsupported Manufacturer Revision '%s'\n", buf);
return -ENODEV;
}
if (client->dev.of_node)
chip_id = (enum chips)of_device_get_match_data(dev);
else
chip_id = id->driver_data;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->id = chip_id;
mutex_init(&data->lock);
memcpy(&data->info, &max20730_info[chip_id], sizeof(data->info));
ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET1);
if (ret < 0)
return ret;
data->mfr_devset1 = ret;
return pmbus_do_probe(client, id, &data->info);
}
static const struct i2c_device_id max20730_id[] = {
{ "max20730", max20730 },
{ "max20734", max20734 },
{ "max20743", max20743 },
{ },
};
MODULE_DEVICE_TABLE(i2c, max20730_id);
static const struct of_device_id max20730_of_match[] = {
{ .compatible = "maxim,max20730", .data = (void *)max20730 },
{ .compatible = "maxim,max20734", .data = (void *)max20734 },
{ .compatible = "maxim,max20743", .data = (void *)max20743 },
{ },
};
MODULE_DEVICE_TABLE(of, max20730_of_match);
static struct i2c_driver max20730_driver = {
.driver = {
.name = "max20730",
.of_match_table = max20730_of_match,
},
.probe = max20730_probe,
.remove = pmbus_do_remove,
.id_table = max20730_id,
};
module_i2c_driver(max20730_driver);
MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("PMBus driver for Maxim MAX20730 / MAX20734 / MAX20743");
MODULE_LICENSE("GPL");