[PATCH v4] misc: eeprom: at24: support pm_runtime control

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Although in the most platforms, the power of eeprom and i2c
are alway on, some platforms disable the eeprom and i2c power
in order to meet low power request.
This patch add the pm_runtime ops to control power to support
all platforms.

Changes since v3:
 - remove redundant calling function
 - change SIMPLE_DEV_PM_OPS to SET_RUNTIME_PM_OPS
 - change supply name

Changes since v2:
 - rebase onto v5.4-rc1
 - pm_runtime_disable and regulator_bulk_disable at
   err return in probe function

Changes since v1:
 - remove redundant code
 - fixup coding style

Signed-off-by: Bibby Hsieh <bibby.hsieh@xxxxxxxxxxxx>
---
 drivers/misc/eeprom/at24.c | 64 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 2cccd82a3106..68ced4f25916 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -22,6 +22,7 @@
 #include <linux/nvmem-provider.h>
 #include <linux/regmap.h>
 #include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
 #include <linux/gpio/consumer.h>
 
 /* Address pointer is 16 bit. */
@@ -67,6 +68,12 @@
  * which won't work on pure SMBus systems.
  */
 
+static const char * const at24_supply_names[] = {
+	"vcc", "i2c",
+};
+
+#define AT24_NUM_SUPPLIES ARRAY_SIZE(at24_supply_names)
+
 struct at24_client {
 	struct i2c_client *client;
 	struct regmap *regmap;
@@ -91,6 +98,8 @@ struct at24_data {
 
 	struct gpio_desc *wp_gpio;
 
+	bool has_supplies;
+	struct regulator_bulk_data supplies[AT24_NUM_SUPPLIES];
 	/*
 	 * Some chips tie up multiple I2C addresses; dummy devices reserve
 	 * them for us, and we'll use them with SMBus calls.
@@ -662,6 +671,17 @@ static int at24_probe(struct i2c_client *client)
 	at24->client[0].client = client;
 	at24->client[0].regmap = regmap;
 
+	regulator_bulk_set_supply_names(at24->supplies,
+					at24_supply_names, AT24_NUM_SUPPLIES);
+	err =  devm_regulator_bulk_get(&at24->client[0].client->dev,
+				       AT24_NUM_SUPPLIES, at24->supplies);
+	if (err == -ENODEV)
+		at24->has_supplies = NULL;
+	else if (err == 0)
+		at24->has_supplies = !err;
+	else
+		return err;
+
 	at24->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_HIGH);
 	if (IS_ERR(at24->wp_gpio))
 		return PTR_ERR(at24->wp_gpio);
@@ -701,6 +721,14 @@ static int at24_probe(struct i2c_client *client)
 
 	i2c_set_clientdata(client, at24);
 
+	if (at24->has_supplies) {
+		err = regulator_bulk_enable(AT24_NUM_SUPPLIES, at24->supplies);
+		if (err) {
+			dev_err(dev, "Failed to enable power regulators\n");
+			return err;
+		}
+	}
+
 	/* enable runtime pm */
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
@@ -713,6 +741,9 @@ static int at24_probe(struct i2c_client *client)
 	pm_runtime_idle(dev);
 	if (err) {
 		pm_runtime_disable(dev);
+		if (at24->has_supplies)
+			regulator_bulk_disable(AT24_NUM_SUPPLIES,
+					       at24->supplies);
 		return -ENODEV;
 	}
 
@@ -725,15 +756,48 @@ static int at24_probe(struct i2c_client *client)
 
 static int at24_remove(struct i2c_client *client)
 {
+	struct at24_data *at24 = i2c_get_clientdata(client);
+
 	pm_runtime_disable(&client->dev);
 	pm_runtime_set_suspended(&client->dev);
+	if (at24->has_supplies)
+		regulator_bulk_disable(AT24_NUM_SUPPLIES, at24->supplies);
+
+	return 0;
+}
+
+static int __maybe_unused at24_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct at24_data *at24 = i2c_get_clientdata(client);
+
+	if (at24->has_supplies)
+		return regulator_bulk_disable(AT24_NUM_SUPPLIES,
+					      at24->supplies);
+
+	return 0;
+}
+
+static int __maybe_unused at24_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct at24_data *at24 = i2c_get_clientdata(client);
+
+	if (at24->has_supplies)
+		return regulator_bulk_enable(AT24_NUM_SUPPLIES,
+					     at24->supplies);
 
 	return 0;
 }
 
+static const struct dev_pm_ops at24_pm_ops = {
+	SET_RUNTIME_PM_OPS(at24_suspend, at24_resume, NULL)
+};
+
 static struct i2c_driver at24_driver = {
 	.driver = {
 		.name = "at24",
+		.pm = &at24_pm_ops,
 		.of_match_table = at24_of_match,
 		.acpi_match_table = ACPI_PTR(at24_acpi_ids),
 	},
-- 
2.18.0




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