[PATCH v4 4/4] pmbus: ltc2978: add regulator support

[<atull@opensource.altera.com>]

From: Alan Tull <atull@opensource.altera.com>

Add simple on/off regulator support for ltc2978 and
other pmbus parts supported by ltc2978.c

Signed-off-by: Alan Tull <atull@opensource.altera.com>

v2: Remove '#include <linux/regulator/machine.h>'
    Only one regulator per pmbus device
    Get regulator_init_data from pdata or device tree

v3: Support multiple regulators for each chip
    Move most code to pmbus_core.c
    fixed values for on/off

v4: fix a #endif comment
    simplify probe code, remove added switch statement
    remove BUG_ON(), add error message and fix num_regulators
---
 drivers/hwmon/pmbus/Kconfig   |    7 +++++++
 drivers/hwmon/pmbus/ltc2978.c |   37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 6e1e493..79117b7 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -56,6 +56,13 @@ config SENSORS_LTC2978
 	  This driver can also be built as a module. If so, the module will
 	  be called ltc2978.
 
+config SENSORS_LTC2978_REGULATOR
+	boolean "Regulator support for LTC2974, LTC2978, LTC3880, and LTC3883"
+	depends on SENSORS_LTC2978 && REGULATOR
+	help
+	  If you say yes here you get regulator support for Linear
+	  Technology LTC2974, LTC2978, LTC3880, and LTC3883.
+
 config SENSORS_MAX16064
 	tristate "Maxim MAX16064"
 	default n
diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c
index e24ed52..422712e 100644
--- a/drivers/hwmon/pmbus/ltc2978.c
+++ b/drivers/hwmon/pmbus/ltc2978.c
@@ -22,6 +22,8 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
 #include "pmbus.h"
 
 enum chips { ltc2974, ltc2977, ltc2978, ltc3880, ltc3883, ltm4676 };
@@ -374,6 +376,30 @@ static const struct i2c_device_id ltc2978_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, ltc2978_id);
 
+#if IS_ENABLED(CONFIG_SENSORS_LTC2978_REGULATOR)
+static const struct regulator_desc ltc2978_reg_desc[] = {
+	PMBUS_REGULATOR("vout_en", 0),
+	PMBUS_REGULATOR("vout_en", 1),
+	PMBUS_REGULATOR("vout_en", 2),
+	PMBUS_REGULATOR("vout_en", 3),
+	PMBUS_REGULATOR("vout_en", 4),
+	PMBUS_REGULATOR("vout_en", 5),
+	PMBUS_REGULATOR("vout_en", 6),
+	PMBUS_REGULATOR("vout_en", 7),
+};
+
+static struct of_regulator_match ltc2978_reg_matches[] = {
+	{ .name = "vout_en0" },
+	{ .name = "vout_en1" },
+	{ .name = "vout_en2" },
+	{ .name = "vout_en3" },
+	{ .name = "vout_en4" },
+	{ .name = "vout_en5" },
+	{ .name = "vout_en6" },
+	{ .name = "vout_en7" },
+};
+#endif /* CONFIG_SENSORS_LTC2978_REGULATOR */
+
 static int ltc2978_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -487,6 +513,17 @@ static int ltc2978_probe(struct i2c_client *client,
 	default:
 		return -ENODEV;
 	}
+
+#if IS_ENABLED(CONFIG_SENSORS_LTC2978_REGULATOR)
+	info->num_regulators = info->pages;
+	info->reg_desc = ltc2978_reg_desc;
+	info->reg_matches = ltc2978_reg_matches;
+	if (info->num_regulators > ARRAY_SIZE(ltc2978_reg_desc)) {
+		dev_err(&client->dev, "num_regulators too large!");
+		info->num_regulators = ARRAY_SIZE(ltc2978_reg_desc);
+	}
+#endif
+
 	return pmbus_do_probe(client, id, info);
 }
 
-- 
1.7.9.5