hwmon: Add driver for STMicroelectronics PM6764 Voltage Regulator

Add the pmbus driver for the STMicroelectronics pm6764 voltage regulator.

the output voltage use the MFR_READ_VOUT 0xD4
vout value returned is linear11

Signed-off-by: Charles Hsu <hsu.yungteng@gmail.com>
[groeck: Fixed various compile errors; marked pm6764tr_of_match __maybe_unused]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -146,6 +146,7 @@ Hardware Monitoring Kernel Drivers
    pc87360
    pc87427
    pcf8591
+   pm6764tr
    pmbus
    powr1220
    pxe1610

Documentation/hwmon/pm6764tr.rst

@@ -0,0 +1,32 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel driver pm6764tr
+======================
+
+Supported chips:
+
+  * ST PM6764TR
+
+    Prefix: 'pm6764tr'
+
+    Addresses scanned: -
+
+    Datasheet: http://www.st.com/resource/en/data_brief/pm6764.pdf
+
+Authors:
+	<hsu.yungteng@gmail.com>
+
+Description:
+------------
+
+This driver supports the STMicroelectronics PM6764TR chip. The PM6764TR is a high
+performance digital controller designed to power Intel’s VR12.5 processors and memories.
+
+The device utilizes digital technology to implement all control and power management
+functions to provide maximum flexibility and performance. The NVM is embedded to store
+custom configurations. The PM6764TR device features up to 4-phase programmable operation.
+
+The PM6764TR supports power state transitions featuring VFDE, and programmable DPM
+maintaining the best efficiency over all loading conditions without compromising transient
+response. The device assures fast and independent protection against load overcurrent,
+under/overvoltage and feedback disconnections.

MAINTAINERS

@@ -13900,6 +13900,13 @@ M:	Logan Gunthorpe <logang@deltatee.com>
 S:	Maintained
 F:	drivers/dma/plx_dma.c
 
+PM6764TR DRIVER
+M:	Charles Hsu	<hsu.yungteng@gmail.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/pm6764tr.rst
+F:	drivers/hwmon/pmbus/pm6764tr.c
+
 PM-GRAPH UTILITY
 M:	"Todd E Brandt" <todd.e.brandt@linux.intel.com>
 L:	linux-pm@vger.kernel.org

drivers/hwmon/pmbus/Kconfig

@@ -220,6 +220,15 @@ config SENSORS_MP2975
 	  This driver can also be built as a module. If so, the module will
 	  be called mp2975.
 
+config SENSORS_PM6764TR
+	tristate "ST PM6764TR"
+	help
+	  If you say yes here you get hardware monitoring support for ST
+	  PM6764TR.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called pm6764tr.
+
 config SENSORS_PXE1610
 	tristate "Infineon PXE1610"
 	help

drivers/hwmon/pmbus/Makefile

@@ -25,6 +25,7 @@ obj-$(CONFIG_SENSORS_MAX31785)	+= max31785.o
 obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
 obj-$(CONFIG_SENSORS_MP2975)	+= mp2975.o
+obj-$(CONFIG_SENSORS_PM6764TR)	+= pm6764tr.o
 obj-$(CONFIG_SENSORS_PXE1610)	+= pxe1610.o
 obj-$(CONFIG_SENSORS_TPS40422)	+= tps40422.o
 obj-$(CONFIG_SENSORS_TPS53679)	+= tps53679.o

drivers/hwmon/pmbus/pm6764tr.c

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for STMicroelectronics digital controller PM6764TR
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+#define PM6764TR_PMBUS_READ_VOUT	0xD4
+
+static int pm6764tr_read_word_data(struct i2c_client *client, int page, int phase, int reg)
+{
+	int ret;
+
+	switch (reg) {
+	case PMBUS_VIRT_READ_VMON:
+		ret = pmbus_read_word_data(client, page, phase, PM6764TR_PMBUS_READ_VOUT);
+		break;
+	default:
+		ret = -ENODATA;
+		break;
+	}
+	return ret;
+}
+
+static struct pmbus_driver_info pm6764tr_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = vid,
+	.format[PSC_TEMPERATURE] = linear,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_POWER] = linear,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN |  PMBUS_HAVE_PIN |
+	    PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT | PMBUS_HAVE_VMON |
+		PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_VOUT |
+		PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
+	.read_word_data = pm6764tr_read_word_data,
+};
+
+static int pm6764tr_probe(struct i2c_client *client)
+{
+	return pmbus_do_probe(client, &pm6764tr_info);
+}
+
+static const struct i2c_device_id pm6764tr_id[] = {
+	{"pm6764tr", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, pm6764tr_id);
+
+static const struct of_device_id __maybe_unused pm6764tr_of_match[] = {
+	{.compatible = "st,pm6764tr"},
+	{}
+};
+
+/* This is the driver that will be inserted */
+static struct i2c_driver pm6764tr_driver = {
+	.driver = {
+		   .name = "pm6764tr",
+		   .of_match_table = of_match_ptr(pm6764tr_of_match),
+		   },
+	.probe_new = pm6764tr_probe,
+	.id_table = pm6764tr_id,
+};
+
+module_i2c_driver(pm6764tr_driver);
+
+MODULE_AUTHOR("Charles Hsu");
+MODULE_DESCRIPTION("PMBus driver for  ST PM6764TR");
+MODULE_LICENSE("GPL");