[PATCH v3 2/2] eeprom: at24: add support for power-supply control

[Eliav Farber <farbere@amazon.com>]

Add an optional gpio regulator to support a power-supply control.
If a gpio power-supply regulator is supplied in the device tree, the
gpio is enabled during probe, and disabled on remove.

Signed-off-by: Eliav Farber <farbere@amazon.com>
---
V2 -> V3:
Apply on top of v6.0-rc1

 drivers/misc/eeprom/at24.c | 40 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 633e1cf08d6e..97f16c361474 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -87,6 +87,8 @@ struct at24_data {
 	struct regulator *vcc_reg;
 	void (*read_post)(unsigned int off, char *buf, size_t count);
 
+	struct regulator *supply;
+
 	/*
 	 * Some chips tie up multiple I2C addresses; dummy devices reserve
 	 * them for us.
@@ -581,6 +583,13 @@ static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)
 	}
 }
 
+static void devm_at24_regulator_disable(void *data)
+{
+	struct at24_data *at24 = data;
+
+	regulator_disable(at24->supply);
+}
+
 static int at24_probe(struct i2c_client *client)
 {
 	struct regmap_config regmap_config = { };
@@ -681,6 +690,37 @@ static int at24_probe(struct i2c_client *client)
 	if (!at24)
 		return -ENOMEM;
 
+	at24->supply = devm_regulator_get_optional(dev, "power");
+	if (IS_ERR(at24->supply)) {
+		err = PTR_ERR(at24->supply);
+		if (err == -ENODEV)
+			at24->supply = NULL;
+		else
+			return dev_err_probe(dev, err,
+					     "failed to get power-supply regulator\n");
+	}
+
+	if (at24->supply) {
+		err = regulator_enable(at24->supply);
+		if (err < 0) {
+			dev_err(dev,
+				"failed to enable power-supply regulator: %d\n",
+				err);
+			return err;
+		}
+
+		err = devm_add_action_or_reset(dev, devm_at24_regulator_disable,
+					       at24);
+		if (err < 0) {
+			dev_err(dev,
+				"failed to add action to disable power-supply regulator: %d\n",
+				err);
+			return err;
+		}
+
+		usleep_range(2000, 3000);
+	}
+
 	mutex_init(&at24->lock);
 	at24->byte_len = byte_len;
 	at24->page_size = page_size;
-- 
2.37.1