hwmon: add MP2993 driver

Add support for MPS VR controller mp2993. This driver exposes
telemetry and limits value readings and writtings.

Signed-off-by: Noah Wang <noahwang.wang@outlook.com>
Link: https://lore.kernel.org/r/SEYPR04MB648203DC017A514837DB1204FAC72@SEYPR04MB6482.apcprd04.prod.outlook.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

3 files changed, 271 insertions, 0 deletions

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 08e82c457356..d875d31ce84c 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -346,6 +346,15 @@ config SENSORS_MP2975
 	  This driver can also be built as a module. If so, the module will
 	  be called mp2975.
 
+config SENSORS_MP2993
+	tristate "MPS MP2993"
+	help
+	  If you say yes here you get hardware monitoring support for MPS
+	  MP2993 Dual Loop Digital Multi-Phase Controller.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called mp2993.
+
 config SENSORS_MP2975_REGULATOR
 	depends on SENSORS_MP2975 && REGULATOR
 	bool "Regulator support for MPS MP2975"
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 2279b3327bbf..312d3f0c0540 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
 obj-$(CONFIG_SENSORS_MP2856)	+= mp2856.o
 obj-$(CONFIG_SENSORS_MP2888)	+= mp2888.o
 obj-$(CONFIG_SENSORS_MP2975)	+= mp2975.o
+obj-$(CONFIG_SENSORS_MP2993)	+= mp2993.o
 obj-$(CONFIG_SENSORS_MP5023)	+= mp5023.o
 obj-$(CONFIG_SENSORS_MP5990)	+= mp5990.o
 obj-$(CONFIG_SENSORS_MPQ7932)	+= mpq7932.o
diff --git a/drivers/hwmon/pmbus/mp2993.c b/drivers/hwmon/pmbus/mp2993.c
new file mode 100644
index 000000000000..944593e13231
--- /dev/null
+++ b/drivers/hwmon/pmbus/mp2993.c
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers(MP2993)
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include "pmbus.h"
+
+#define MP2993_VOUT_OVUV_UINT	125
+#define MP2993_VOUT_OVUV_DIV	64
+#define MP2993_VIN_LIMIT_UINT	1
+#define MP2993_VIN_LIMIT_DIV	8
+#define MP2993_READ_VIN_UINT	1
+#define MP2993_READ_VIN_DIV	32
+
+#define MP2993_PAGE_NUM	2
+
+#define MP2993_RAIL1_FUNC	(PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
+							PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT | \
+							PMBUS_HAVE_TEMP | PMBUS_HAVE_PIN | \
+							PMBUS_HAVE_IIN | \
+							PMBUS_HAVE_STATUS_VOUT | \
+							PMBUS_HAVE_STATUS_IOUT | \
+							PMBUS_HAVE_STATUS_TEMP | \
+							PMBUS_HAVE_STATUS_INPUT)
+
+#define MP2993_RAIL2_FUNC	(PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | \
+							 PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP | \
+							 PMBUS_HAVE_STATUS_VOUT | \
+							 PMBUS_HAVE_STATUS_IOUT | \
+							 PMBUS_HAVE_STATUS_TEMP | \
+							 PMBUS_HAVE_STATUS_INPUT)
+
+/* Converts a linear11 data exponent to a specified value */
+static u16 mp2993_linear11_exponent_transfer(u16 word, u16 expect_exponent)
+{
+	s16 exponent, mantissa, target_exponent;
+
+	exponent = ((s16)word) >> 11;
+	mantissa = ((s16)((word & 0x7ff) << 5)) >> 5;
+	target_exponent = (s16)((expect_exponent & 0x1f) << 11) >> 11;
+
+	if (exponent > target_exponent)
+		mantissa = mantissa << (exponent - target_exponent);
+	else
+		mantissa = mantissa >> (target_exponent - exponent);
+
+	return (mantissa & 0x7ff) | ((expect_exponent << 11) & 0xf800);
+}
+
+static int
+mp2993_set_vout_format(struct i2c_client *client, int page, int format)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(client, PMBUS_VOUT_MODE, format);
+}
+
+static int mp2993_identify(struct i2c_client *client, struct pmbus_driver_info *info)
+{
+	int ret;
+
+	/* Set vout to direct format for rail1. */
+	ret = mp2993_set_vout_format(client, 0, PB_VOUT_MODE_DIRECT);
+	if (ret < 0)
+		return ret;
+
+	/* Set vout to direct format for rail2. */
+	return mp2993_set_vout_format(client, 1, PB_VOUT_MODE_DIRECT);
+}
+
+static int mp2993_read_word_data(struct i2c_client *client, int page, int phase,
+				 int reg)
+{
+	int ret;
+
+	switch (reg) {
+	case PMBUS_VOUT_OV_FAULT_LIMIT:
+	case PMBUS_VOUT_UV_FAULT_LIMIT:
+		ret = pmbus_read_word_data(client, page, phase, reg);
+		if (ret < 0)
+			return ret;
+
+		ret = DIV_ROUND_CLOSEST(ret * MP2993_VOUT_OVUV_UINT, MP2993_VOUT_OVUV_DIV);
+		break;
+	case PMBUS_OT_FAULT_LIMIT:
+	case PMBUS_OT_WARN_LIMIT:
+		/*
+		 * The MP2993 ot fault limit value and ot warn limit value
+		 * per rail are always the same, so only PMBUS_OT_FAULT_LIMIT
+		 * and PMBUS_OT_WARN_LIMIT register in page 0 are defined to
+		 * indicates the limit value.
+		 */
+		ret = pmbus_read_word_data(client, 0, phase, reg);
+		break;
+	case PMBUS_READ_VIN:
+		/* The MP2993 vin scale is (1/32V)/Lsb */
+		ret = pmbus_read_word_data(client, page, phase, reg);
+		if (ret < 0)
+			return ret;
+
+		ret = DIV_ROUND_CLOSEST((ret & GENMASK(9, 0)) * MP2993_READ_VIN_UINT,
+					MP2993_READ_VIN_DIV);
+		break;
+	case PMBUS_VIN_OV_FAULT_LIMIT:
+	case PMBUS_VIN_OV_WARN_LIMIT:
+	case PMBUS_VIN_UV_WARN_LIMIT:
+	case PMBUS_VIN_UV_FAULT_LIMIT:
+		/* The MP2993 vin limit scale is (1/8V)/Lsb */
+		ret = pmbus_read_word_data(client, page, phase, reg);
+		if (ret < 0)
+			return ret;
+
+		ret = DIV_ROUND_CLOSEST((ret & GENMASK(7, 0)) * MP2993_VIN_LIMIT_UINT,
+					MP2993_VIN_LIMIT_DIV);
+		break;
+	case PMBUS_READ_IOUT:
+	case PMBUS_READ_IIN:
+	case PMBUS_IIN_OC_WARN_LIMIT:
+	case PMBUS_IOUT_OC_FAULT_LIMIT:
+	case PMBUS_IOUT_OC_WARN_LIMIT:
+	case PMBUS_READ_VOUT:
+	case PMBUS_READ_PIN:
+	case PMBUS_READ_POUT:
+	case PMBUS_READ_TEMPERATURE_1:
+		ret = -ENODATA;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static int mp2993_write_word_data(struct i2c_client *client, int page, int reg,
+				  u16 word)
+{
+	int ret;
+
+	switch (reg) {
+	case PMBUS_VOUT_OV_FAULT_LIMIT:
+	case PMBUS_VOUT_UV_FAULT_LIMIT:
+		ret = DIV_ROUND_CLOSEST(word * MP2993_VOUT_OVUV_DIV, MP2993_VOUT_OVUV_UINT);
+		ret = pmbus_write_word_data(client, 0, reg, ret);
+		break;
+	case PMBUS_OT_FAULT_LIMIT:
+	case PMBUS_OT_WARN_LIMIT:
+		/*
+		 * The MP2993 ot fault limit value and ot warn limit value
+		 * per rail are always the same, so only PMBUS_OT_FAULT_LIMIT
+		 * and PMBUS_OT_WARN_LIMIT register in page 0 are defined to
+		 * config the ot limit value.
+		 */
+		ret = pmbus_write_word_data(client, 0, reg, word);
+		break;
+	case PMBUS_VIN_OV_FAULT_LIMIT:
+	case PMBUS_VIN_OV_WARN_LIMIT:
+	case PMBUS_VIN_UV_WARN_LIMIT:
+	case PMBUS_VIN_UV_FAULT_LIMIT:
+		/* The MP2993 vin limit scale is (1/8V)/Lsb */
+		ret = pmbus_write_word_data(client, 0, reg,
+					    DIV_ROUND_CLOSEST(word * MP2993_VIN_LIMIT_DIV,
+							      MP2993_VIN_LIMIT_UINT));
+		break;
+	case PMBUS_IIN_OC_WARN_LIMIT:
+		/*
+		 * The PMBUS_IIN_OC_WARN_LIMIT of MP2993 is linear11 format,
+		 * and the exponent is a constant value(5'b00000)， so the
+		 * exponent of word parameter should be converted to 5'b00000.
+		 */
+		ret = pmbus_write_word_data(client, page, reg,
+					    mp2993_linear11_exponent_transfer(word, 0x00));
+		break;
+		//
+	case PMBUS_IOUT_OC_FAULT_LIMIT:
+	case PMBUS_IOUT_OC_WARN_LIMIT:
+		/*
+		 * The PMBUS_IOUT_OC_FAULT_LIMIT and PMBUS_IOUT_OC_WARN_LIMIT
+		 * of MP2993 can be regarded as linear11 format, and the
+		 * exponent is a 5'b00001 or 5'b00000. To ensure a larger
+		 * range of limit value, so the exponent of word parameter
+		 * should be converted to 5'b00001.
+		 */
+		ret = pmbus_write_word_data(client, page, reg,
+					    mp2993_linear11_exponent_transfer(word, 0x01));
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static struct pmbus_driver_info mp2993_info = {
+	.pages = MP2993_PAGE_NUM,
+	.format[PSC_VOLTAGE_IN] = direct,
+	.format[PSC_CURRENT_IN] = linear,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_TEMPERATURE] = direct,
+	.format[PSC_POWER] = linear,
+	.format[PSC_VOLTAGE_OUT] = direct,
+
+	.m[PSC_VOLTAGE_OUT] = 1,
+	.R[PSC_VOLTAGE_OUT] = 3,
+	.b[PSC_VOLTAGE_OUT] = 0,
+
+	.m[PSC_VOLTAGE_IN] = 1,
+	.R[PSC_VOLTAGE_IN] = 0,
+	.b[PSC_VOLTAGE_IN] = 0,
+
+	.m[PSC_TEMPERATURE] = 1,
+	.R[PSC_TEMPERATURE] = 0,
+	.b[PSC_TEMPERATURE] = 0,
+
+	.func[0] = MP2993_RAIL1_FUNC,
+	.func[1] = MP2993_RAIL2_FUNC,
+	.read_word_data = mp2993_read_word_data,
+	.write_word_data = mp2993_write_word_data,
+	.identify = mp2993_identify,
+};
+
+static int mp2993_probe(struct i2c_client *client)
+{
+	return pmbus_do_probe(client, &mp2993_info);
+}
+
+static const struct i2c_device_id mp2993_id[] = {
+	{"mp2993", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, mp2993_id);
+
+static const struct of_device_id __maybe_unused mp2993_of_match[] = {
+	{.compatible = "mps,mp2993"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, mp2993_of_match);
+
+static struct i2c_driver mp2993_driver = {
+	.driver = {
+		.name = "mp2993",
+		.of_match_table = mp2993_of_match,
+	},
+	.probe = mp2993_probe,
+	.id_table = mp2993_id,
+};
+
+module_i2c_driver(mp2993_driver);
+
+MODULE_AUTHOR("Noah Wang <noahwang.wang@outlook.com>");
+MODULE_DESCRIPTION("PMBus driver for MPS MP2993");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);