From: Zoie Lin <zoie.lin@mediatek.com>

Incorporate support for the dovdd regulator, which supplies an
additional power source to the EEPROM.

Signed-off-by: Zoie Lin <zoie.lin@mediatek.com>
---
 drivers/misc/eeprom/at24.c | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 572333ead5fb..b96f6eda3ad2 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -86,6 +86,7 @@ struct at24_data {
 
 	struct nvmem_device *nvmem;
 	struct regulator *vcc_reg;
+	struct regulator *dovdd_reg;
 	void (*read_post)(unsigned int off, char *buf, size_t count);
 
 	/*
@@ -697,6 +698,14 @@ static int at24_probe(struct i2c_client *client)
 	if (IS_ERR(at24->vcc_reg))
 		return PTR_ERR(at24->vcc_reg);
 
+	at24->dovdd_reg = devm_regulator_get_optional(dev, "dovdd");
+	if (IS_ERR(at24->dovdd_reg)) {
+		if (PTR_ERR(at24->dovdd_reg) == -ENODEV)
+			at24->dovdd_reg = NULL;
+		else
+			return PTR_ERR(at24->dovdd_reg);
+	}
+
 	writable = !(flags & AT24_FLAG_READONLY);
 	if (writable) {
 		at24->write_max = min_t(unsigned int,
@@ -754,6 +763,14 @@ static int at24_probe(struct i2c_client *client)
 			return err;
 		}
 
+		if (at24->dovdd_reg != NULL) {
+			err = regulator_enable(at24->dovdd_reg);
+			if (err) {
+				dev_err(dev, "Failed to enable dovdd regulator\n");
+				return err;
+			}
+		}
+
 		pm_runtime_set_active(dev);
 	}
 	pm_runtime_enable(dev);
@@ -761,8 +778,11 @@ static int at24_probe(struct i2c_client *client)
 	at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
 	if (IS_ERR(at24->nvmem)) {
 		pm_runtime_disable(dev);
-		if (!pm_runtime_status_suspended(dev))
+		if (!pm_runtime_status_suspended(dev)) {
 			regulator_disable(at24->vcc_reg);
+			if (at24->dovdd_reg != NULL)
+				regulator_disable(at24->dovdd_reg);
+		}
 		return dev_err_probe(dev, PTR_ERR(at24->nvmem),
 				     "failed to register nvmem\n");
 	}
@@ -804,8 +824,11 @@ static void at24_remove(struct i2c_client *client)
 
 	pm_runtime_disable(&client->dev);
 	if (acpi_dev_state_d0(&client->dev)) {
-		if (!pm_runtime_status_suspended(&client->dev))
+		if (!pm_runtime_status_suspended(&client->dev)) {
 			regulator_disable(at24->vcc_reg);
+			if (at24->dovdd_reg != NULL)
+				regulator_disable(at24->dovdd_reg);
+		}
 		pm_runtime_set_suspended(&client->dev);
 	}
 }
@@ -815,14 +838,24 @@ 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->dovdd_reg != NULL)
+		regulator_disable(at24->dovdd_reg);
+
 	return regulator_disable(at24->vcc_reg);
 }
 
 static int __maybe_unused at24_resume(struct device *dev)
 {
+	int err;
 	struct i2c_client *client = to_i2c_client(dev);
 	struct at24_data *at24 = i2c_get_clientdata(client);
 
+	if (at24->dovdd_reg != NULL) {
+		err = regulator_enable(at24->dovdd_reg);
+		if (err)
+			return err;
+	}
+
 	return regulator_enable(at24->vcc_reg);
 }
 
-- 
2.18.0

On Fri, Apr 26, 2024 at 06:29:47PM +0800, zoie.lin wrote:
> From: Zoie Lin <zoie.lin@mediatek.com>
> 
> Incorporate support for the dovdd regulator, which supplies an
> additional power source to the EEPROM.

It would be helpful if you could supply some additional information
about what this supply is, why we can't tell if it's supposed to be
there or not and so on.