max15301.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Hardware monitoring driver for Maxim MAX15301
  4 *
  5 * Copyright (c) 2021 Flextronics International Sweden AB
  6 *
  7 * Even though the specification does not specifically mention it,
  8 * extensive empirical testing has revealed that auto-detection of
  9 * limit-registers will fail in a random fashion unless the delay
 10 * parameter is set to above about 80us. The default delay is set
 11 * to 100us to include some safety margin.
 12 */
 13
 14#include <linux/kernel.h>
 15#include <linux/module.h>
 16#include <linux/init.h>
 17#include <linux/err.h>
 18#include <linux/slab.h>
 19#include <linux/i2c.h>
 20#include <linux/ktime.h>
 21#include <linux/delay.h>
 22#include <linux/pmbus.h>
 23#include "pmbus.h"
 24
 25static const struct i2c_device_id max15301_id[] = {
 26	{ "bmr461" },
 27	{ "max15301" },
 28	{ "max15303" },
 29	{}
 30};
 31MODULE_DEVICE_TABLE(i2c, max15301_id);
 32
 33struct max15301_data {
 34	int id;
 35	struct pmbus_driver_info info;
 36};
 37
 38#define to_max15301_data(x)  container_of(x, struct max15301_data, info)
 39
 40#define MAX15301_WAIT_TIME		100	/* us	*/
 41
 42static ushort delay = MAX15301_WAIT_TIME;
 43module_param(delay, ushort, 0644);
 44MODULE_PARM_DESC(delay, "Delay between chip accesses in us");
 45
 46static struct max15301_data max15301_data = {
 47	.info = {
 48		.pages = 1,
 49		.func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
 50			| PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
 51			| PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
 52			| PMBUS_HAVE_STATUS_TEMP
 53			| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT,
 54	}
 55};
 56
 57static int max15301_probe(struct i2c_client *client)
 58{
 59	int status;
 60	u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
 61	const struct i2c_device_id *mid;
 62	struct pmbus_driver_info *info = &max15301_data.info;
 63
 64	if (!i2c_check_functionality(client->adapter,
 65				     I2C_FUNC_SMBUS_READ_BYTE_DATA
 66				     | I2C_FUNC_SMBUS_BLOCK_DATA))
 67		return -ENODEV;
 68
 69	status = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, device_id);
 70	if (status < 0) {
 71		dev_err(&client->dev, "Failed to read Device Id\n");
 72		return status;
 73	}
 74	for (mid = max15301_id; mid->name[0]; mid++) {
 75		if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
 76			break;
 77	}
 78	if (!mid->name[0]) {
 79		dev_err(&client->dev, "Unsupported device\n");
 80		return -ENODEV;
 81	}
 82
 83	info->access_delay = delay;
 84
 85	return pmbus_do_probe(client, info);
 86}
 87
 88static struct i2c_driver max15301_driver = {
 89	.driver = {
 90		   .name = "max15301",
 91		   },
 92	.probe = max15301_probe,
 93	.id_table = max15301_id,
 94};
 95
 96module_i2c_driver(max15301_driver);
 97
 98MODULE_AUTHOR("Erik Rosen <erik.rosen@metormote.com>");
 99MODULE_DESCRIPTION("PMBus driver for Maxim MAX15301");
100MODULE_LICENSE("GPL");
101MODULE_IMPORT_NS("PMBUS");