dps920ab.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for Delta DPS920AB PSU
 *
 * Copyright (C) 2021 Delta Networks, Inc.
 * Copyright (C) 2021 Sartura Ltd.
 */

#include <linux/debugfs.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include "pmbus.h"

struct dps920ab_data {
	char *mfr_model;
	char *mfr_id;
};

static int dps920ab_read_word_data(struct i2c_client *client, int page, int phase, int reg)
{
	/*
	 * This masks commands which are not supported.
	 * PSU advertises that all features are supported,
	 * in reality that unfortunately is not true.
	 * So enable only those that the datasheet confirms.
	 */
	switch (reg) {
	case PMBUS_FAN_COMMAND_1:
	case PMBUS_IOUT_OC_WARN_LIMIT:
	case PMBUS_STATUS_WORD:
	case PMBUS_READ_VIN:
	case PMBUS_READ_IIN:
	case PMBUS_READ_VOUT:
	case PMBUS_READ_IOUT:
	case PMBUS_READ_TEMPERATURE_1:
	case PMBUS_READ_TEMPERATURE_2:
	case PMBUS_READ_TEMPERATURE_3:
	case PMBUS_READ_FAN_SPEED_1:
	case PMBUS_READ_POUT:
	case PMBUS_READ_PIN:
	case PMBUS_MFR_VOUT_MIN:
	case PMBUS_MFR_VOUT_MAX:
	case PMBUS_MFR_IOUT_MAX:
	case PMBUS_MFR_POUT_MAX:
		return pmbus_read_word_data(client, page, phase, reg);
	default:
		return -ENXIO;
	}
}

static int dps920ab_write_word_data(struct i2c_client *client, int page, int reg,
				    u16 word)
{
	/*
	 * This masks commands which are not supported.
	 * PSU only has one R/W register and that is
	 * for the fan.
	 */
	switch (reg) {
	case PMBUS_FAN_COMMAND_1:
		return pmbus_write_word_data(client, page, reg, word);
	default:
		return -EACCES;
	}
}

static struct pmbus_driver_info dps920ab_info = {
	.pages = 1,

	.format[PSC_VOLTAGE_IN] = linear,
	.format[PSC_VOLTAGE_OUT] = linear,
	.format[PSC_CURRENT_IN] = linear,
	.format[PSC_CURRENT_OUT] = linear,
	.format[PSC_POWER] = linear,
	.format[PSC_FAN] = linear,
	.format[PSC_TEMPERATURE] = linear,

	.func[0] =
		PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_PIN |
		PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT |
		PMBUS_HAVE_TEMP  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 |
		PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12 |
		PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT |
		PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
	.read_word_data = dps920ab_read_word_data,
	.write_word_data = dps920ab_write_word_data,
};

static int dps920ab_mfr_id_show(struct seq_file *s, void *data)
{
	struct dps920ab_data *priv = s->private;

	seq_printf(s, "%s\n", priv->mfr_id);

	return 0;
}

DEFINE_SHOW_ATTRIBUTE(dps920ab_mfr_id);

static int dps920ab_mfr_model_show(struct seq_file *s, void *data)
{
	struct dps920ab_data *priv = s->private;

	seq_printf(s, "%s\n", priv->mfr_model);

	return 0;
}

DEFINE_SHOW_ATTRIBUTE(dps920ab_mfr_model);

static void dps920ab_init_debugfs(struct dps920ab_data *data, struct i2c_client *client)
{
	struct dentry *debugfs_dir;
	struct dentry *root;

	root = pmbus_get_debugfs_dir(client);
	if (!root)
		return;

	debugfs_dir = debugfs_create_dir(client->name, root);

	debugfs_create_file("mfr_id",
			    0400,
			    debugfs_dir,
			    data,
			    &dps920ab_mfr_id_fops);

	debugfs_create_file("mfr_model",
			    0400,
			    debugfs_dir,
			    data,
			    &dps920ab_mfr_model_fops);
}

static int dps920ab_probe(struct i2c_client *client)
{
	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
	struct dps920ab_data *data;
	int ret;

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

	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;
	}

	buf[ret] = '\0';
	if (ret != 5 || strncmp(buf, "DELTA", 5)) {
		buf[ret] = '\0';
		dev_err(&client->dev, "Unsupported Manufacturer ID '%s'\n", buf);
		return -ENODEV;
	}
	data->mfr_id = devm_kstrdup(&client->dev, buf, GFP_KERNEL);
	if (!data->mfr_id)
		return -ENOMEM;

	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
	if (ret < 0) {
		dev_err(&client->dev, "Failed to read Manufacturer Model\n");
		return ret;
	}

	buf[ret] = '\0';
	if (ret != 11 || strncmp(buf, "DPS-920AB", 9)) {
		dev_err(&client->dev, "Unsupported Manufacturer Model '%s'\n", buf);
		return -ENODEV;
	}
	data->mfr_model = devm_kstrdup(&client->dev, buf, GFP_KERNEL);
	if (!data->mfr_model)
		return -ENOMEM;

	ret = pmbus_do_probe(client, &dps920ab_info);
	if (ret)
		return ret;

	dps920ab_init_debugfs(data, client);

	return 0;
}

static const struct of_device_id __maybe_unused dps920ab_of_match[] = {
	{ .compatible = "delta,dps920ab", },
	{}
};

MODULE_DEVICE_TABLE(of, dps920ab_of_match);

static struct i2c_driver dps920ab_driver = {
	.driver = {
		   .name = "dps920ab",
		   .of_match_table = of_match_ptr(dps920ab_of_match),
	},
	.probe = dps920ab_probe,
};

module_i2c_driver(dps920ab_driver);

MODULE_AUTHOR("Robert Marko <robert.marko@sartura.hr>");
MODULE_DESCRIPTION("PMBus driver for Delta DPS920AB PSU");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS(PMBUS);