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// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pmbus.h>
#include "pmbus.h"
/* LTC4286 register */
#define LTC4286_MFR_CONFIG1 0xF2
/* LTC4286 configuration */
#define VRANGE_SELECT_BIT BIT(1)
#define LTC4286_MFR_ID_SIZE 3
/*
* Initialize the MBR as default settings which is referred to LTC4286 datasheet
* (March 22, 2022 version) table 3 page 16
*/
static struct pmbus_driver_info ltc4286_info = {
.pages = 1,
.format[PSC_VOLTAGE_IN] = direct,
.format[PSC_VOLTAGE_OUT] = direct,
.format[PSC_CURRENT_OUT] = direct,
.format[PSC_POWER] = direct,
.format[PSC_TEMPERATURE] = direct,
.m[PSC_VOLTAGE_IN] = 32,
.b[PSC_VOLTAGE_IN] = 0,
.R[PSC_VOLTAGE_IN] = 1,
.m[PSC_VOLTAGE_OUT] = 32,
.b[PSC_VOLTAGE_OUT] = 0,
.R[PSC_VOLTAGE_OUT] = 1,
.m[PSC_CURRENT_OUT] = 1024,
.b[PSC_CURRENT_OUT] = 0,
/*
* The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
* However, the rsense value that user input is micro ohm.
* Thus, the MBR setting which involves rsense should be shifted by 6 digits.
*/
.R[PSC_CURRENT_OUT] = 3 - 6,
.m[PSC_POWER] = 1,
.b[PSC_POWER] = 0,
/*
* The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
* However, the rsense value that user input is micro ohm.
* Thus, the MBR setting which involves rsense should be shifted by 6 digits.
*/
.R[PSC_POWER] = 4 - 6,
.m[PSC_TEMPERATURE] = 1,
.b[PSC_TEMPERATURE] = 273,
.R[PSC_TEMPERATURE] = 0,
.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT |
PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP,
};
static const struct i2c_device_id ltc4286_id[] = {
{ "ltc4286", 0 },
{ "ltc4287", 1 },
{}
};
MODULE_DEVICE_TABLE(i2c, ltc4286_id);
static int ltc4286_probe(struct i2c_client *client)
{
int ret;
const struct i2c_device_id *mid;
u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
struct pmbus_driver_info *info;
u32 rsense;
int vrange_nval, vrange_oval;
ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, block_buffer);
if (ret < 0) {
return dev_err_probe(&client->dev, ret,
"Failed to read manufacturer id\n");
}
/*
* Refer to ltc4286 datasheet page 20
* the manufacturer id is LTC
*/
if (ret != LTC4286_MFR_ID_SIZE ||
strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
return dev_err_probe(&client->dev, -ENODEV,
"Manufacturer id mismatch\n");
}
ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, block_buffer);
if (ret < 0) {
return dev_err_probe(&client->dev, ret,
"Failed to read manufacturer model\n");
}
for (mid = ltc4286_id; mid->name[0]; mid++) {
if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
break;
}
if (!mid->name[0])
return dev_err_probe(&client->dev, -ENODEV,
"Unsupported device\n");
if (of_property_read_u32(client->dev.of_node,
"shunt-resistor-micro-ohms", &rsense))
rsense = 300; /* 0.3 mOhm if not set via DT */
if (rsense == 0)
return -EINVAL;
/* Check for the latter MBR value won't overflow */
if (rsense > (INT_MAX / 1024))
return -EINVAL;
info = devm_kmemdup(&client->dev, <c4286_info, sizeof(*info),
GFP_KERNEL);
if (!info)
return -ENOMEM;
/* Check MFR1 CONFIG register bit 1 VRANGE_SELECT before driver loading */
vrange_oval = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
if (vrange_oval < 0)
return dev_err_probe(&client->dev, vrange_oval,
"Failed to read manufacturer configuration one\n");
vrange_nval = vrange_oval;
if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) {
vrange_nval &=
~VRANGE_SELECT_BIT; /* VRANGE_SELECT = 0, 25.6 volts */
info->m[PSC_VOLTAGE_IN] = 128;
info->m[PSC_VOLTAGE_OUT] = 128;
info->m[PSC_POWER] = 4 * rsense;
} else {
vrange_nval |=
VRANGE_SELECT_BIT; /* VRANGE_SELECT = 1, 102.4 volts */
info->m[PSC_POWER] = rsense;
}
if (vrange_nval != vrange_oval) {
/* Set MFR1 CONFIG register bit 1 VRANGE_SELECT */
ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1,
vrange_nval);
if (ret < 0)
return dev_err_probe(&client->dev, ret,
"Failed to set vrange\n");
}
info->m[PSC_CURRENT_OUT] = 1024 * rsense;
return pmbus_do_probe(client, info);
}
static const struct of_device_id ltc4286_of_match[] = {
{ .compatible = "lltc,ltc4286" },
{ .compatible = "lltc,ltc4287" },
{}
};
static struct i2c_driver ltc4286_driver = {
.driver = {
.name = "ltc4286",
.of_match_table = ltc4286_of_match,
},
.probe = ltc4286_probe,
.id_table = ltc4286_id,
};
module_i2c_driver(ltc4286_driver);
MODULE_AUTHOR("Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>");
MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");
MODULE_LICENSE("GPL");
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