hwmon: (pmbus) Add client driver for IR35221

IR35221 is a Digital DC-DC Multiphase Converter

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
[groeck: Preserve alphabetic order in Kconfig;
	add missing break statements (from Dan Carpenter);
	add missing error checks]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 337 insertions, 0 deletions

diff --git a/drivers/hwmon/pmbus/ir35221.c b/drivers/hwmon/pmbus/ir35221.c
new file mode 100644
index 000000000000..8b906b44484b
--- /dev/null
+++ b/drivers/hwmon/pmbus/ir35221.c
@@ -0,0 +1,337 @@
+/*
+ * Hardware monitoring driver for IR35221
+ *
+ * Copyright (C) IBM Corporation 2017.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+#define IR35221_MFR_VIN_PEAK		0xc5
+#define IR35221_MFR_VOUT_PEAK		0xc6
+#define IR35221_MFR_IOUT_PEAK		0xc7
+#define IR35221_MFR_TEMP_PEAK		0xc8
+#define IR35221_MFR_VIN_VALLEY		0xc9
+#define IR35221_MFR_VOUT_VALLEY		0xca
+#define IR35221_MFR_IOUT_VALLEY		0xcb
+#define IR35221_MFR_TEMP_VALLEY		0xcc
+
+static long ir35221_reg2data(int data, enum pmbus_sensor_classes class)
+{
+	s16 exponent;
+	s32 mantissa;
+	long val;
+
+	/* We only modify LINEAR11 formats */
+	exponent = ((s16)data) >> 11;
+	mantissa = ((s16)((data & 0x7ff) << 5)) >> 5;
+
+	val = mantissa * 1000L;
+
+	/* scale result to micro-units for power sensors */
+	if (class == PSC_POWER)
+		val = val * 1000L;
+
+	if (exponent >= 0)
+		val <<= exponent;
+	else
+		val >>= -exponent;
+
+	return val;
+}
+
+#define MAX_MANTISSA	(1023 * 1000)
+#define MIN_MANTISSA	(511 * 1000)
+
+static u16 ir35221_data2reg(long val, enum pmbus_sensor_classes class)
+{
+	s16 exponent = 0, mantissa;
+	bool negative = false;
+
+	if (val == 0)
+		return 0;
+
+	if (val < 0) {
+		negative = true;
+		val = -val;
+	}
+
+	/* Power is in uW. Convert to mW before converting. */
+	if (class == PSC_POWER)
+		val = DIV_ROUND_CLOSEST(val, 1000L);
+
+	/* Reduce large mantissa until it fits into 10 bit */
+	while (val >= MAX_MANTISSA && exponent < 15) {
+		exponent++;
+		val >>= 1;
+	}
+	/* Increase small mantissa to improve precision */
+	while (val < MIN_MANTISSA && exponent > -15) {
+		exponent--;
+		val <<= 1;
+	}
+
+	/* Convert mantissa from milli-units to units */
+	mantissa = DIV_ROUND_CLOSEST(val, 1000);
+
+	/* Ensure that resulting number is within range */
+	if (mantissa > 0x3ff)
+		mantissa = 0x3ff;
+
+	/* restore sign */
+	if (negative)
+		mantissa = -mantissa;
+
+	/* Convert to 5 bit exponent, 11 bit mantissa */
+	return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
+}
+
+static u16 ir35221_scale_result(s16 data, int shift,
+				enum pmbus_sensor_classes class)
+{
+	long val;
+
+	val = ir35221_reg2data(data, class);
+
+	if (shift < 0)
+		val >>= -shift;
+	else
+		val <<= shift;
+
+	return ir35221_data2reg(val, class);
+}
+
+static int ir35221_read_word_data(struct i2c_client *client, int page, int reg)
+{
+	int ret;
+
+	switch (reg) {
+	case PMBUS_IOUT_OC_FAULT_LIMIT:
+	case PMBUS_IOUT_OC_WARN_LIMIT:
+		ret = pmbus_read_word_data(client, page, reg);
+		if (ret < 0)
+			break;
+		ret = ir35221_scale_result(ret, 1, PSC_CURRENT_OUT);
+		break;
+	case PMBUS_VIN_OV_FAULT_LIMIT:
+	case PMBUS_VIN_OV_WARN_LIMIT:
+	case PMBUS_VIN_UV_WARN_LIMIT:
+		ret = pmbus_read_word_data(client, page, reg);
+		ret = ir35221_scale_result(ret, -4, PSC_VOLTAGE_IN);
+		break;
+	case PMBUS_IIN_OC_WARN_LIMIT:
+		ret = pmbus_read_word_data(client, page, reg);
+		if (ret < 0)
+			break;
+		ret = ir35221_scale_result(ret, -1, PSC_CURRENT_IN);
+		break;
+	case PMBUS_READ_VIN:
+		ret = pmbus_read_word_data(client, page, PMBUS_READ_VIN);
+		if (ret < 0)
+			break;
+		ret = ir35221_scale_result(ret, -5, PSC_VOLTAGE_IN);
+		break;
+	case PMBUS_READ_IIN:
+		ret = pmbus_read_word_data(client, page, PMBUS_READ_IIN);
+		if (ret < 0)
+			break;
+		if (page == 0)
+			ret = ir35221_scale_result(ret, -4, PSC_CURRENT_IN);
+		else
+			ret = ir35221_scale_result(ret, -5, PSC_CURRENT_IN);
+		break;
+	case PMBUS_READ_POUT:
+		ret = pmbus_read_word_data(client, page, PMBUS_READ_POUT);
+		if (ret < 0)
+			break;
+		ret = ir35221_scale_result(ret, -1, PSC_POWER);
+		break;
+	case PMBUS_READ_PIN:
+		ret = pmbus_read_word_data(client, page, PMBUS_READ_PIN);
+		if (ret < 0)
+			break;
+		ret = ir35221_scale_result(ret, -1, PSC_POWER);
+		break;
+	case PMBUS_READ_IOUT:
+		ret = pmbus_read_word_data(client, page, PMBUS_READ_IOUT);
+		if (ret < 0)
+			break;
+		if (page == 0)
+			ret = ir35221_scale_result(ret, -1, PSC_CURRENT_OUT);
+		else
+			ret = ir35221_scale_result(ret, -2, PSC_CURRENT_OUT);
+		break;
+	case PMBUS_VIRT_READ_VIN_MAX:
+		ret = pmbus_read_word_data(client, page, IR35221_MFR_VIN_PEAK);
+		if (ret < 0)
+			break;
+		ret = ir35221_scale_result(ret, -5, PSC_VOLTAGE_IN);
+		break;
+	case PMBUS_VIRT_READ_VOUT_MAX:
+		ret = pmbus_read_word_data(client, page, IR35221_MFR_VOUT_PEAK);
+		break;
+	case PMBUS_VIRT_READ_IOUT_MAX:
+		ret = pmbus_read_word_data(client, page, IR35221_MFR_IOUT_PEAK);
+		if (ret < 0)
+			break;
+		if (page == 0)
+			ret = ir35221_scale_result(ret, -1, PSC_CURRENT_IN);
+		else
+			ret = ir35221_scale_result(ret, -2, PSC_CURRENT_IN);
+		break;
+	case PMBUS_VIRT_READ_TEMP_MAX:
+		ret = pmbus_read_word_data(client, page, IR35221_MFR_TEMP_PEAK);
+		break;
+	case PMBUS_VIRT_READ_VIN_MIN:
+		ret = pmbus_read_word_data(client, page,
+					   IR35221_MFR_VIN_VALLEY);
+		if (ret < 0)
+			break;
+		ret = ir35221_scale_result(ret, -5, PSC_VOLTAGE_IN);
+		break;
+	case PMBUS_VIRT_READ_VOUT_MIN:
+		ret = pmbus_read_word_data(client, page,
+					   IR35221_MFR_VOUT_VALLEY);
+		break;
+	case PMBUS_VIRT_READ_IOUT_MIN:
+		ret = pmbus_read_word_data(client, page,
+					   IR35221_MFR_IOUT_VALLEY);
+		if (ret < 0)
+			break;
+		if (page == 0)
+			ret = ir35221_scale_result(ret, -1, PSC_CURRENT_IN);
+		else
+			ret = ir35221_scale_result(ret, -2, PSC_CURRENT_IN);
+		break;
+	case PMBUS_VIRT_READ_TEMP_MIN:
+		ret = pmbus_read_word_data(client, page,
+					   IR35221_MFR_TEMP_VALLEY);
+		break;
+	default:
+		ret = -ENODATA;
+		break;
+	}
+
+	return ret;
+}
+
+static int ir35221_write_word_data(struct i2c_client *client, int page, int reg,
+				   u16 word)
+{
+	int ret;
+	u16 val;
+
+	switch (reg) {
+	case PMBUS_IOUT_OC_FAULT_LIMIT:
+	case PMBUS_IOUT_OC_WARN_LIMIT:
+		val = ir35221_scale_result(word, -1, PSC_CURRENT_OUT);
+		ret = pmbus_write_word_data(client, page, reg, val);
+		break;
+	case PMBUS_VIN_OV_FAULT_LIMIT:
+	case PMBUS_VIN_OV_WARN_LIMIT:
+	case PMBUS_VIN_UV_WARN_LIMIT:
+		val = ir35221_scale_result(word, 4, PSC_VOLTAGE_IN);
+		ret = pmbus_write_word_data(client, page, reg, val);
+		break;
+	case PMBUS_IIN_OC_WARN_LIMIT:
+		val = ir35221_scale_result(word, 1, PSC_CURRENT_IN);
+		ret = pmbus_write_word_data(client, page, reg, val);
+		break;
+	default:
+		ret = -ENODATA;
+		break;
+	}
+
+	return ret;
+}
+
+static int ir35221_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct pmbus_driver_info *info;
+	u8 buf[I2C_SMBUS_BLOCK_MAX];
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_BYTE_DATA
+				| I2C_FUNC_SMBUS_READ_WORD_DATA
+				| I2C_FUNC_SMBUS_READ_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 PMBUS_MFR_ID\n");
+		return ret;
+	}
+	if (ret != 2 || strncmp(buf, "RI", strlen("RI"))) {
+		dev_err(&client->dev, "MFR_ID unrecognised\n");
+		return -ENODEV;
+	}
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read PMBUS_MFR_MODEL\n");
+		return ret;
+	}
+	if (ret != 2 || !(buf[0] == 0x6c && buf[1] == 0x00)) {
+		dev_err(&client->dev, "MFR_MODEL unrecognised\n");
+		return -ENODEV;
+	}
+
+	info = devm_kzalloc(&client->dev, sizeof(struct pmbus_driver_info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->write_word_data = ir35221_write_word_data;
+	info->read_word_data = ir35221_read_word_data;
+
+	info->pages = 2;
+	info->format[PSC_VOLTAGE_IN] = linear;
+	info->format[PSC_VOLTAGE_OUT] = linear;
+	info->format[PSC_CURRENT_IN] = linear;
+	info->format[PSC_CURRENT_OUT] = linear;
+	info->format[PSC_POWER] = linear;
+	info->format[PSC_TEMPERATURE] = linear;
+
+	info->func[0] = PMBUS_HAVE_VIN
+		| PMBUS_HAVE_VOUT | PMBUS_HAVE_IIN
+		| PMBUS_HAVE_IOUT | PMBUS_HAVE_PIN
+		| PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
+		| PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT
+		| PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP;
+	info->func[1] = info->func[0];
+
+	return pmbus_do_probe(client, id, info);
+}
+
+static const struct i2c_device_id ir35221_id[] = {
+	{"ir35221", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, ir35221_id);
+
+static struct i2c_driver ir35221_driver = {
+	.driver = {
+		.name	= "ir35221",
+	},
+	.probe		= ir35221_probe,
+	.remove		= pmbus_do_remove,
+	.id_table	= ir35221_id,
+};
+
+module_i2c_driver(ir35221_driver);
+
+MODULE_AUTHOR("Samuel Mendoza-Jonas <sam@mendozajonas.com");
+MODULE_DESCRIPTION("PMBus driver for IR35221");
+MODULE_LICENSE("GPL");