max20730.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for MAX20710, MAX20730, MAX20734, and MAX20743 Integrated,
 * Step-Down Switching Regulators
 *
 * Copyright 2019 Google LLC.
 * Copyright 2020 Maxim Integrated
 */

#include <linux/bits.h>
#include <linux/debugfs.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 {
	max20710,
	max20730,
	max20734,
	max20743
};

enum {
	MAX20730_DEBUGFS_VOUT_MIN = 0,
	MAX20730_DEBUGFS_FREQUENCY,
	MAX20730_DEBUGFS_PG_DELAY,
	MAX20730_DEBUGFS_INTERNAL_GAIN,
	MAX20730_DEBUGFS_BOOT_VOLTAGE,
	MAX20730_DEBUGFS_OUT_V_RAMP_RATE,
	MAX20730_DEBUGFS_OC_PROTECT_MODE,
	MAX20730_DEBUGFS_SS_TIMING,
	MAX20730_DEBUGFS_IMAX,
	MAX20730_DEBUGFS_OPERATION,
	MAX20730_DEBUGFS_ON_OFF_CONFIG,
	MAX20730_DEBUGFS_SMBALERT_MASK,
	MAX20730_DEBUGFS_VOUT_MODE,
	MAX20730_DEBUGFS_VOUT_COMMAND,
	MAX20730_DEBUGFS_VOUT_MAX,
	MAX20730_DEBUGFS_NUM_ENTRIES
};

struct max20730_data {
	enum chips id;
	struct pmbus_driver_info info;
	struct mutex lock;	/* Used to protect against parallel writes */
	u16 mfr_devset1;
	u16 mfr_devset2;
	u16 mfr_voutmin;
	u32 vout_voltage_divider[2];
};

#define to_max20730_data(x)  container_of(x, struct max20730_data, info)

#define VOLT_FROM_REG(val)	DIV_ROUND_CLOSEST((val), 1 << 9)

#define PMBUS_SMB_ALERT_MASK	0x1B

#define MAX20730_MFR_VOUT_MIN	0xd1
#define MAX20730_MFR_DEVSET1	0xd2
#define MAX20730_MFR_DEVSET2	0xd3

#define MAX20730_MFR_VOUT_MIN_MASK		GENMASK(9, 0)
#define MAX20730_MFR_VOUT_MIN_BIT_POS		0

#define MAX20730_MFR_DEVSET1_RGAIN_MASK		(BIT(13) | BIT(14))
#define MAX20730_MFR_DEVSET1_OTP_MASK		(BIT(11) | BIT(12))
#define MAX20730_MFR_DEVSET1_VBOOT_MASK		(BIT(8) | BIT(9))
#define MAX20730_MFR_DEVSET1_OCP_MASK		(BIT(5) | BIT(6))
#define MAX20730_MFR_DEVSET1_FSW_MASK		GENMASK(4, 2)
#define MAX20730_MFR_DEVSET1_TSTAT_MASK		(BIT(0) | BIT(1))

#define MAX20730_MFR_DEVSET1_RGAIN_BIT_POS	13
#define MAX20730_MFR_DEVSET1_OTP_BIT_POS	11
#define MAX20730_MFR_DEVSET1_VBOOT_BIT_POS	8
#define MAX20730_MFR_DEVSET1_OCP_BIT_POS	5
#define MAX20730_MFR_DEVSET1_FSW_BIT_POS	2
#define MAX20730_MFR_DEVSET1_TSTAT_BIT_POS	0

#define MAX20730_MFR_DEVSET2_IMAX_MASK		GENMASK(10, 8)
#define MAX20730_MFR_DEVSET2_VRATE		(BIT(6) | BIT(7))
#define MAX20730_MFR_DEVSET2_OCPM_MASK		BIT(5)
#define MAX20730_MFR_DEVSET2_SS_MASK		(BIT(0) | BIT(1))

#define MAX20730_MFR_DEVSET2_IMAX_BIT_POS	8
#define MAX20730_MFR_DEVSET2_VRATE_BIT_POS	6
#define MAX20730_MFR_DEVSET2_OCPM_BIT_POS	5
#define MAX20730_MFR_DEVSET2_SS_BIT_POS		0

#define DEBUG_FS_DATA_MAX			16

struct max20730_debugfs_data {
	struct i2c_client *client;
	int debugfs_entries[MAX20730_DEBUGFS_NUM_ENTRIES];
};

#define to_psu(x, y) container_of((x), \
			struct max20730_debugfs_data, debugfs_entries[(y)])

#ifdef CONFIG_DEBUG_FS
static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
				     size_t count, loff_t *ppos)
{
	int ret, len;
	int *idxp = file->private_data;
	int idx = *idxp;
	struct max20730_debugfs_data *psu = to_psu(idxp, idx);
	const struct pmbus_driver_info *info;
	const struct max20730_data *data;
	char tbuf[DEBUG_FS_DATA_MAX] = { 0 };
	u16 val;

	info = pmbus_get_driver_info(psu->client);
	data = to_max20730_data(info);

	switch (idx) {
	case MAX20730_DEBUGFS_VOUT_MIN:
		ret = VOLT_FROM_REG(data->mfr_voutmin * 10000);
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d.%d\n",
				ret / 10000, ret % 10000);
		break;
	case MAX20730_DEBUGFS_FREQUENCY:
		val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_FSW_MASK)
			>> MAX20730_MFR_DEVSET1_FSW_BIT_POS;

		if (val == 0)
			ret = 400;
		else if (val == 1)
			ret = 500;
		else if (val == 2 || val == 3)
			ret = 600;
		else if (val == 4)
			ret = 700;
		else if (val == 5)
			ret = 800;
		else
			ret = 900;
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
		break;
	case MAX20730_DEBUGFS_PG_DELAY:
		val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_TSTAT_MASK)
			>> MAX20730_MFR_DEVSET1_TSTAT_BIT_POS;

		if (val == 0)
			len = strlcpy(tbuf, "2000\n", DEBUG_FS_DATA_MAX);
		else if (val == 1)
			len = strlcpy(tbuf, "125\n", DEBUG_FS_DATA_MAX);
		else if (val == 2)
			len = strlcpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX);
		else
			len = strlcpy(tbuf, "32\n", DEBUG_FS_DATA_MAX);
		break;
	case MAX20730_DEBUGFS_INTERNAL_GAIN:
		val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_RGAIN_MASK)
			>> MAX20730_MFR_DEVSET1_RGAIN_BIT_POS;

		if (data->id == max20734) {
			/* AN6209 */
			if (val == 0)
				len = strlcpy(tbuf, "0.8\n", DEBUG_FS_DATA_MAX);
			else if (val == 1)
				len = strlcpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX);
			else if (val == 2)
				len = strlcpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX);
			else
				len = strlcpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX);
		} else if (data->id == max20730 || data->id == max20710) {
			/* AN6042 or AN6140 */
			if (val == 0)
				len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
			else if (val == 1)
				len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
			else if (val == 2)
				len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
			else
				len = strlcpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX);
		} else if (data->id == max20743) {
			/* AN6042 */
			if (val == 0)
				len = strlcpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX);
			else if (val == 1)
				len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX);
			else if (val == 2)
				len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX);
			else
				len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX);
		} else {
			len = strlcpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX);
		}
		break;
	case MAX20730_DEBUGFS_BOOT_VOLTAGE:
		val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_VBOOT_MASK)
			>> MAX20730_MFR_DEVSET1_VBOOT_BIT_POS;

		if (val == 0)
			len = strlcpy(tbuf, "0.6484\n", DEBUG_FS_DATA_MAX);
		else if (val == 1)
			len = strlcpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX);
		else if (val == 2)
			len = strlcpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX);
		else
			len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
		break;
	case MAX20730_DEBUGFS_OUT_V_RAMP_RATE:
		val = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_VRATE)
			>> MAX20730_MFR_DEVSET2_VRATE_BIT_POS;

		if (val == 0)
			len = strlcpy(tbuf, "4\n", DEBUG_FS_DATA_MAX);
		else if (val == 1)
			len = strlcpy(tbuf, "2\n", DEBUG_FS_DATA_MAX);
		else if (val == 2)
			len = strlcpy(tbuf, "1\n", DEBUG_FS_DATA_MAX);
		else
			len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
		break;
	case MAX20730_DEBUGFS_OC_PROTECT_MODE:
		ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_OCPM_MASK)
			>> MAX20730_MFR_DEVSET2_OCPM_BIT_POS;
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
		break;
	case MAX20730_DEBUGFS_SS_TIMING:
		val = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_SS_MASK)
			>> MAX20730_MFR_DEVSET2_SS_BIT_POS;

		if (val == 0)
			len = strlcpy(tbuf, "0.75\n", DEBUG_FS_DATA_MAX);
		else if (val == 1)
			len = strlcpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX);
		else if (val == 2)
			len = strlcpy(tbuf, "3\n", DEBUG_FS_DATA_MAX);
		else
			len = strlcpy(tbuf, "6\n", DEBUG_FS_DATA_MAX);
		break;
	case MAX20730_DEBUGFS_IMAX:
		ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_IMAX_MASK)
			>> MAX20730_MFR_DEVSET2_IMAX_BIT_POS;
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
		break;
	case MAX20730_DEBUGFS_OPERATION:
		ret = i2c_smbus_read_byte_data(psu->client, PMBUS_OPERATION);
		if (ret < 0)
			return ret;
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
		break;
	case MAX20730_DEBUGFS_ON_OFF_CONFIG:
		ret = i2c_smbus_read_byte_data(psu->client, PMBUS_ON_OFF_CONFIG);
		if (ret < 0)
			return ret;
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
		break;
	case MAX20730_DEBUGFS_SMBALERT_MASK:
		ret = i2c_smbus_read_word_data(psu->client,
					       PMBUS_SMB_ALERT_MASK);
		if (ret < 0)
			return ret;
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
		break;
	case MAX20730_DEBUGFS_VOUT_MODE:
		ret = i2c_smbus_read_byte_data(psu->client, PMBUS_VOUT_MODE);
		if (ret < 0)
			return ret;
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
		break;
	case MAX20730_DEBUGFS_VOUT_COMMAND:
		ret = i2c_smbus_read_word_data(psu->client, PMBUS_VOUT_COMMAND);
		if (ret < 0)
			return ret;

		ret = VOLT_FROM_REG(ret * 10000);
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX,
				"%d.%d\n", ret / 10000, ret % 10000);
		break;
	case MAX20730_DEBUGFS_VOUT_MAX:
		ret = i2c_smbus_read_word_data(psu->client, PMBUS_VOUT_MAX);
		if (ret < 0)
			return ret;

		ret = VOLT_FROM_REG(ret * 10000);
		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX,
				"%d.%d\n", ret / 10000, ret % 10000);
		break;
	default:
		len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
	}

	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
}

static const struct file_operations max20730_fops = {
	.llseek = noop_llseek,
	.read = max20730_debugfs_read,
	.write = NULL,
	.open = simple_open,
};

static int max20730_init_debugfs(struct i2c_client *client,
				 struct max20730_data *data)
{
	int ret, i;
	struct dentry *debugfs;
	struct dentry *max20730_dir;
	struct max20730_debugfs_data *psu;

	ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET2);
	if (ret < 0)
		return ret;
	data->mfr_devset2 = ret;

	ret = i2c_smbus_read_word_data(client, MAX20730_MFR_VOUT_MIN);
	if (ret < 0)
		return ret;
	data->mfr_voutmin = ret;

	psu = devm_kzalloc(&client->dev, sizeof(*psu), GFP_KERNEL);
	if (!psu)
		return -ENOMEM;
	psu->client = client;

	debugfs = pmbus_get_debugfs_dir(client);
	if (!debugfs)
		return -ENOENT;

	max20730_dir = debugfs_create_dir(client->name, debugfs);

	for (i = 0; i < MAX20730_DEBUGFS_NUM_ENTRIES; ++i)
		psu->debugfs_entries[i] = i;

	debugfs_create_file("vout_min", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_VOUT_MIN],
			    &max20730_fops);
	debugfs_create_file("frequency", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_FREQUENCY],
			    &max20730_fops);
	debugfs_create_file("power_good_delay", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_PG_DELAY],
			    &max20730_fops);
	debugfs_create_file("internal_gain", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_INTERNAL_GAIN],
			    &max20730_fops);
	debugfs_create_file("boot_voltage", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_BOOT_VOLTAGE],
			    &max20730_fops);
	debugfs_create_file("out_voltage_ramp_rate", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_OUT_V_RAMP_RATE],
			    &max20730_fops);
	debugfs_create_file("oc_protection_mode", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_OC_PROTECT_MODE],
			    &max20730_fops);
	debugfs_create_file("soft_start_timing", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_SS_TIMING],
			    &max20730_fops);
	debugfs_create_file("imax", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_IMAX],
			    &max20730_fops);
	debugfs_create_file("operation", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_OPERATION],
			    &max20730_fops);
	debugfs_create_file("on_off_config", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_ON_OFF_CONFIG],
			    &max20730_fops);
	debugfs_create_file("smbalert_mask", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_SMBALERT_MASK],
			    &max20730_fops);
	debugfs_create_file("vout_mode", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_VOUT_MODE],
			    &max20730_fops);
	debugfs_create_file("vout_command", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_VOUT_COMMAND],
			    &max20730_fops);
	debugfs_create_file("vout_max", 0444, max20730_dir,
			    &psu->debugfs_entries[MAX20730_DEBUGFS_VOUT_MAX],
			    &max20730_fops);

	return 0;
}
#else
static int max20730_init_debugfs(struct i2c_client *client,
				 struct max20730_data *data)
{
	return 0;
}
#endif /* CONFIG_DEBUG_FS */

static const struct i2c_device_id max20730_id[];

/*
 * 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] = {
	[max20710] = { 6200, 8000, 9700, 11600 },
	[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;
	case PMBUS_READ_VOUT:
		ret = pmbus_read_word_data(client, page, phase, reg);
		if (ret > 0 && data->vout_voltage_divider[0] && data->vout_voltage_divider[1]) {
			u64 temp = DIV_ROUND_CLOSEST_ULL((u64)ret * data->vout_voltage_divider[1],
							 data->vout_voltage_divider[0]);
			ret = clamp_val(temp, 0, 0xffff);
		}
		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[] = {
	[max20710] = {
		.pages = 1,
		.read_word_data = max20730_read_word_data,
		.write_word_data = max20730_write_word_data,

		/* Source : Maxim AN6140 and 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,

		.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 |
			PMBUS_HAVE_STATUS_INPUT,
	},
	[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 |
			PMBUS_HAVE_STATUS_INPUT,
	},
	[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 |
			PMBUS_HAVE_STATUS_INPUT,
	},
	[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 |
			PMBUS_HAVE_STATUS_INPUT,
	},
};

static int max20730_probe(struct i2c_client *client)
{
	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 = i2c_match_id(max20730_id, client)->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));
	if (of_property_read_u32_array(client->dev.of_node, "vout-voltage-divider",
				       data->vout_voltage_divider,
				       ARRAY_SIZE(data->vout_voltage_divider)) != 0)
		memset(data->vout_voltage_divider, 0, sizeof(data->vout_voltage_divider));
	if (data->vout_voltage_divider[1] < data->vout_voltage_divider[0]) {
		dev_err(dev,
			"The total resistance of voltage divider is less than output resistance\n");
		return -EINVAL;
	}

	ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET1);
	if (ret < 0)
		return ret;
	data->mfr_devset1 = ret;

	ret = pmbus_do_probe(client, &data->info);
	if (ret < 0)
		return ret;

	ret = max20730_init_debugfs(client, data);
	if (ret)
		dev_warn(dev, "Failed to register debugfs: %d\n",
			 ret);

	return 0;
}

static const struct i2c_device_id max20730_id[] = {
	{ "max20710", max20710 },
	{ "max20730", max20730 },
	{ "max20734", max20734 },
	{ "max20743", max20743 },
	{ },
};

MODULE_DEVICE_TABLE(i2c, max20730_id);

static const struct of_device_id max20730_of_match[] = {
	{ .compatible = "maxim,max20710", .data = (void *)max20710 },
	{ .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_new = max20730_probe,
	.id_table = max20730_id,
};

module_i2c_driver(max20730_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("PMBus driver for Maxim MAX20710 / MAX20730 / MAX20734 / MAX20743");
MODULE_LICENSE("GPL");