hwmon: (pmbus/pli1209bc) Add regulator support

Add regulator support for PLI1209BC Digital Supervisor.
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
Link: https://lore.kernel.org/r/21b0cdb6dd72654effa451d3b1636ecd07b160e9.1645435888.git.sylv@sylv.ioSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/Kconfig

@@ -326,6 +326,13 @@ config SENSORS_PLI1209BC
 	  This driver can also be built as a module. If so, the module will
 	  be called pli1209bc.
 
+config SENSORS_PLI1209BC_REGULATOR
+	bool "Regulator support for PLI1209BC"
+	depends on SENSORS_PLI1209BC && REGULATOR
+	help
+	  If you say yes here you get regulator support for Vicor PLI1209BC
+	  Digital Supervisor.
+
 config SENSORS_PM6764TR
 	tristate "ST PM6764TR"
 	help

drivers/hwmon/pmbus/pli1209bc.c

@@ -8,6 +8,7 @@
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/pmbus.h>
+#include <linux/regulator/driver.h>
 #include "pmbus.h"
 
 /*
@@ -33,11 +34,37 @@ static int pli1209bc_read_word_data(struct i2c_client *client, int page,
 			return data;
 		data = sign_extend32(data, 15) * 10;
 		return clamp_val(data, -32768, 32767) & 0xffff;
+	/*
+	 * PMBUS_READ_VOUT and PMBUS_READ_TEMPERATURE_1 return invalid data
+	 * when the BCM is turned off. Since it is not possible to return
+	 * ENODATA error, return zero instead.
+	 */
+	case PMBUS_READ_VOUT:
+	case PMBUS_READ_TEMPERATURE_1:
+		data = pmbus_read_word_data(client, page, phase,
+					    PMBUS_STATUS_WORD);
+		if (data < 0)
+			return data;
+		if (data & PB_STATUS_POWER_GOOD_N)
+			return 0;
+		return pmbus_read_word_data(client, page, phase, reg);
 	default:
 		return -ENODATA;
 	}
 }
 
+#if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR)
+static const struct regulator_desc pli1209bc_reg_desc = {
+	.name = "vout2",
+	.id = 1,
+	.of_match = of_match_ptr("vout2"),
+	.regulators_node = of_match_ptr("regulators"),
+	.ops = &pmbus_regulator_ops,
+	.type = REGULATOR_VOLTAGE,
+	.owner = THIS_MODULE,
+};
+#endif
+
 static struct pmbus_driver_info pli1209bc_info = {
 	.pages = 2,
 	.format[PSC_VOLTAGE_IN] = direct,
@@ -75,6 +102,10 @@ static struct pmbus_driver_info pli1209bc_info = {
 	    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
 	    | PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_INPUT,
 	.read_word_data = pli1209bc_read_word_data,
+#if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR)
+	.num_regulators = 1,
+	.reg_desc = &pli1209bc_reg_desc,
+#endif
 };
 
 static int pli1209bc_probe(struct i2c_client *client)