1 files changed, 401 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c
new file mode 100644
index 000000000..839b957bc
--- /dev/null
+++ b/drivers/hwmon/pmbus/max31785.c
@@ -0,0 +1,401 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017 IBM Corp.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include "pmbus.h"
+
+enum max31785_regs {
+	MFR_REVISION		= 0x9b,
+	MFR_FAN_CONFIG		= 0xf1,
+};
+
+#define MAX31785			0x3030
+#define MAX31785A			0x3040
+
+#define MFR_FAN_CONFIG_DUAL_TACH	BIT(12)
+
+#define MAX31785_NR_PAGES		23
+#define MAX31785_NR_FAN_PAGES		6
+
+static int max31785_read_byte_data(struct i2c_client *client, int page,
+				   int reg)
+{
+	if (page < MAX31785_NR_PAGES)
+		return -ENODATA;
+
+	switch (reg) {
+	case PMBUS_VOUT_MODE:
+		return -ENOTSUPP;
+	case PMBUS_FAN_CONFIG_12:
+		return pmbus_read_byte_data(client, page - MAX31785_NR_PAGES,
+					    reg);
+	}
+
+	return -ENODATA;
+}
+
+static int max31785_write_byte(struct i2c_client *client, int page, u8 value)
+{
+	if (page < MAX31785_NR_PAGES)
+		return -ENODATA;
+
+	return -ENOTSUPP;
+}
+
+static int max31785_read_long_data(struct i2c_client *client, int page,
+				   int reg, u32 *data)
+{
+	unsigned char cmdbuf[1];
+	unsigned char rspbuf[4];
+	int rc;
+
+	struct i2c_msg msg[2] = {
+		{
+			.addr = client->addr,
+			.flags = 0,
+			.len = sizeof(cmdbuf),
+			.buf = cmdbuf,
+		},
+		{
+			.addr = client->addr,
+			.flags = I2C_M_RD,
+			.len = sizeof(rspbuf),
+			.buf = rspbuf,
+		},
+	};
+
+	cmdbuf[0] = reg;
+
+	rc = pmbus_set_page(client, page, 0xff);
+	if (rc < 0)
+		return rc;
+
+	rc = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+	if (rc < 0)
+		return rc;
+
+	*data = (rspbuf[0] << (0 * 8)) | (rspbuf[1] << (1 * 8)) |
+		(rspbuf[2] << (2 * 8)) | (rspbuf[3] << (3 * 8));
+
+	return rc;
+}
+
+static int max31785_get_pwm(struct i2c_client *client, int page)
+{
+	int rv;
+
+	rv = pmbus_get_fan_rate_device(client, page, 0, percent);
+	if (rv < 0)
+		return rv;
+	else if (rv >= 0x8000)
+		return 0;
+	else if (rv >= 0x2711)
+		return 0x2710;
+
+	return rv;
+}
+
+static int max31785_get_pwm_mode(struct i2c_client *client, int page)
+{
+	int config;
+	int command;
+
+	config = pmbus_read_byte_data(client, page, PMBUS_FAN_CONFIG_12);
+	if (config < 0)
+		return config;
+
+	command = pmbus_read_word_data(client, page, 0xff, PMBUS_FAN_COMMAND_1);
+	if (command < 0)
+		return command;
+
+	if (config & PB_FAN_1_RPM)
+		return (command >= 0x8000) ? 3 : 2;
+
+	if (command >= 0x8000)
+		return 3;
+	else if (command >= 0x2711)
+		return 0;
+
+	return 1;
+}
+
+static int max31785_read_word_data(struct i2c_client *client, int page,
+				   int phase, int reg)
+{
+	u32 val;
+	int rv;
+
+	switch (reg) {
+	case PMBUS_READ_FAN_SPEED_1:
+		if (page < MAX31785_NR_PAGES)
+			return -ENODATA;
+
+		rv = max31785_read_long_data(client, page - MAX31785_NR_PAGES,
+					     reg, &val);
+		if (rv < 0)
+			return rv;
+
+		rv = (val >> 16) & 0xffff;
+		break;
+	case PMBUS_FAN_COMMAND_1:
+		/*
+		 * PMBUS_FAN_COMMAND_x is probed to judge whether or not to
+		 * expose fan control registers.
+		 *
+		 * Don't expose fan_target attribute for virtual pages.
+		 */
+		rv = (page >= MAX31785_NR_PAGES) ? -ENOTSUPP : -ENODATA;
+		break;
+	case PMBUS_VIRT_PWM_1:
+		rv = max31785_get_pwm(client, page);
+		break;
+	case PMBUS_VIRT_PWM_ENABLE_1:
+		rv = max31785_get_pwm_mode(client, page);
+		break;
+	default:
+		rv = -ENODATA;
+		break;
+	}
+
+	return rv;
+}
+
+static inline u32 max31785_scale_pwm(u32 sensor_val)
+{
+	/*
+	 * The datasheet describes the accepted value range for manual PWM as
+	 * [0, 0x2710], while the hwmon pwmX sysfs interface accepts values in
+	 * [0, 255]. The MAX31785 uses DIRECT mode to scale the FAN_COMMAND
+	 * registers and in PWM mode the coefficients are m=1, b=0, R=2. The
+	 * important observation here is that 0x2710 == 10000 == 100 * 100.
+	 *
+	 * R=2 (== 10^2 == 100) accounts for scaling the value provided at the
+	 * sysfs interface into the required hardware resolution, but it does
+	 * not yet yield a value that we can write to the device (this initial
+	 * scaling is handled by pmbus_data2reg()). Multiplying by 100 below
+	 * translates the parameter value into the percentage units required by
+	 * PMBus, and then we scale back by 255 as required by the hwmon pwmX
+	 * interface to yield the percentage value at the appropriate
+	 * resolution for hardware.
+	 */
+	return (sensor_val * 100) / 255;
+}
+
+static int max31785_pwm_enable(struct i2c_client *client, int page,
+				    u16 word)
+{
+	int config = 0;
+	int rate;
+
+	switch (word) {
+	case 0:
+		rate = 0x7fff;
+		break;
+	case 1:
+		rate = pmbus_get_fan_rate_cached(client, page, 0, percent);
+		if (rate < 0)
+			return rate;
+		rate = max31785_scale_pwm(rate);
+		break;
+	case 2:
+		config = PB_FAN_1_RPM;
+		rate = pmbus_get_fan_rate_cached(client, page, 0, rpm);
+		if (rate < 0)
+			return rate;
+		break;
+	case 3:
+		rate = 0xffff;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return pmbus_update_fan(client, page, 0, config, PB_FAN_1_RPM, rate);
+}
+
+static int max31785_write_word_data(struct i2c_client *client, int page,
+				    int reg, u16 word)
+{
+	switch (reg) {
+	case PMBUS_VIRT_PWM_1:
+		return pmbus_update_fan(client, page, 0, 0, PB_FAN_1_RPM,
+					max31785_scale_pwm(word));
+	case PMBUS_VIRT_PWM_ENABLE_1:
+		return max31785_pwm_enable(client, page, word);
+	default:
+		break;
+	}
+
+	return -ENODATA;
+}
+
+#define MAX31785_FAN_FUNCS \
+	(PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_PWM12)
+
+#define MAX31785_TEMP_FUNCS \
+	(PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP)
+
+#define MAX31785_VOUT_FUNCS \
+	(PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT)
+
+static const struct pmbus_driver_info max31785_info = {
+	.pages = MAX31785_NR_PAGES,
+
+	.write_word_data = max31785_write_word_data,
+	.read_byte_data = max31785_read_byte_data,
+	.read_word_data = max31785_read_word_data,
+	.write_byte = max31785_write_byte,
+
+	/* RPM */
+	.format[PSC_FAN] = direct,
+	.m[PSC_FAN] = 1,
+	.b[PSC_FAN] = 0,
+	.R[PSC_FAN] = 0,
+	/* PWM */
+	.format[PSC_PWM] = direct,
+	.m[PSC_PWM] = 1,
+	.b[PSC_PWM] = 0,
+	.R[PSC_PWM] = 2,
+	.func[0] = MAX31785_FAN_FUNCS,
+	.func[1] = MAX31785_FAN_FUNCS,
+	.func[2] = MAX31785_FAN_FUNCS,
+	.func[3] = MAX31785_FAN_FUNCS,
+	.func[4] = MAX31785_FAN_FUNCS,
+	.func[5] = MAX31785_FAN_FUNCS,
+
+	.format[PSC_TEMPERATURE] = direct,
+	.m[PSC_TEMPERATURE] = 1,
+	.b[PSC_TEMPERATURE] = 0,
+	.R[PSC_TEMPERATURE] = 2,
+	.func[6]  = MAX31785_TEMP_FUNCS,
+	.func[7]  = MAX31785_TEMP_FUNCS,
+	.func[8]  = MAX31785_TEMP_FUNCS,
+	.func[9]  = MAX31785_TEMP_FUNCS,
+	.func[10] = MAX31785_TEMP_FUNCS,
+	.func[11] = MAX31785_TEMP_FUNCS,
+	.func[12] = MAX31785_TEMP_FUNCS,
+	.func[13] = MAX31785_TEMP_FUNCS,
+	.func[14] = MAX31785_TEMP_FUNCS,
+	.func[15] = MAX31785_TEMP_FUNCS,
+	.func[16] = MAX31785_TEMP_FUNCS,
+
+	.format[PSC_VOLTAGE_OUT] = direct,
+	.m[PSC_VOLTAGE_OUT] = 1,
+	.b[PSC_VOLTAGE_OUT] = 0,
+	.R[PSC_VOLTAGE_OUT] = 0,
+	.func[17] = MAX31785_VOUT_FUNCS,
+	.func[18] = MAX31785_VOUT_FUNCS,
+	.func[19] = MAX31785_VOUT_FUNCS,
+	.func[20] = MAX31785_VOUT_FUNCS,
+	.func[21] = MAX31785_VOUT_FUNCS,
+	.func[22] = MAX31785_VOUT_FUNCS,
+};
+
+static int max31785_configure_dual_tach(struct i2c_client *client,
+					struct pmbus_driver_info *info)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < MAX31785_NR_FAN_PAGES; i++) {
+		ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
+		if (ret < 0)
+			return ret;
+
+		ret = i2c_smbus_read_word_data(client, MFR_FAN_CONFIG);
+		if (ret < 0)
+			return ret;
+
+		if (ret & MFR_FAN_CONFIG_DUAL_TACH) {
+			int virtual = MAX31785_NR_PAGES + i;
+
+			info->pages = virtual + 1;
+			info->func[virtual] |= PMBUS_HAVE_FAN12;
+			info->func[virtual] |= PMBUS_PAGE_VIRTUAL;
+		}
+	}
+
+	return 0;
+}
+
+static int max31785_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct pmbus_driver_info *info;
+	bool dual_tach = false;
+	s64 ret;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE_DATA |
+				     I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	*info = max31785_info;
+
+	ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 255);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_read_word_data(client, MFR_REVISION);
+	if (ret < 0)
+		return ret;
+
+	if (ret == MAX31785A) {
+		dual_tach = true;
+	} else if (ret == MAX31785) {
+		if (!strcmp("max31785a", client->name))
+			dev_warn(dev, "Expected max3175a, found max31785: cannot provide secondary tachometer readings\n");
+	} else {
+		return -ENODEV;
+	}
+
+	if (dual_tach) {
+		ret = max31785_configure_dual_tach(client, info);
+		if (ret < 0)
+			return ret;
+	}
+
+	return pmbus_do_probe(client, info);
+}
+
+static const struct i2c_device_id max31785_id[] = {
+	{ "max31785", 0 },
+	{ "max31785a", 0 },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(i2c, max31785_id);
+
+static const struct of_device_id max31785_of_match[] = {
+	{ .compatible = "maxim,max31785" },
+	{ .compatible = "maxim,max31785a" },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, max31785_of_match);
+
+static struct i2c_driver max31785_driver = {
+	.driver = {
+		.name = "max31785",
+		.of_match_table = max31785_of_match,
+	},
+	.probe_new = max31785_probe,
+	.remove = pmbus_do_remove,
+	.id_table = max31785_id,
+};
+
+module_i2c_driver(max31785_driver);
+
+MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
+MODULE_DESCRIPTION("PMBus driver for the Maxim MAX31785");
+MODULE_LICENSE("GPL");