diff options
Diffstat (limited to 'drivers/hwmon/pmbus/max15301.c')
| -rw-r--r-- | drivers/hwmon/pmbus/max15301.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/max15301.c b/drivers/hwmon/pmbus/max15301.c new file mode 100644 index 000000000000..0b6f88428ea8 --- /dev/null +++ b/drivers/hwmon/pmbus/max15301.c @@ -0,0 +1,190 @@ +// 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); |