diff options
Diffstat (limited to 'drivers/hwmon/pmbus/ltc4286.c')
| -rw-r--r-- | drivers/hwmon/pmbus/ltc4286.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/ltc4286.c b/drivers/hwmon/pmbus/ltc4286.c new file mode 100644 index 000000000000..9e7ceeb7e789 --- /dev/null +++ b/drivers/hwmon/pmbus/ltc4286.c @@ -0,0 +1,175 @@ +// 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"); |