[PATCH v2] mfd: max77620: publish module aliases with variant match data

[Pengpeng Hou <hppiscas@163.com>]

MAX77620 can be built as a module, but its I2C ID table is not exported
and it has no OF match table to provide OF aliases.

Publish both tables and obtain the chip variant through
i2c_get_match_data(). Adding OF matching alone is insufficient: a fallback
compatible can match the OF table while client->name has no corresponding
I2C ID. Dereferencing i2c_client_get_device_id() would then be invalid.

Use pointers to chip IDs in both tables. This also keeps MAX77620, whose
enum value is zero, distinguishable from missing match data. Leave the
variant-specific regmap configuration and child devices unchanged.

The issue was found by our static-analysis tool and manually reviewed.

Fixes: 0d084ee9ba87 ("mfd: max77620: Allow building as a module")
Assisted-by: gpt 5
Signed-off-by: Pengpeng Hou <hppiscas@163.com>
---
Changes since v1:
- use the author's real name
- address the matching-path issue Lee asked to review: populate OF data
  and migrate probe to i2c_get_match_data() with a missing-data check
- use non-NULL pointers for all variants, including enum value zero

Previous version:
https://lore.kernel.org/all/20260905134051.66545-1-hppiscas@163.com/

 drivers/mfd/max77620.c |   29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/mfd/max77620.c b/drivers/mfd/max77620.c
index c4f89a9681f34792d24c5b75c4b88df84b3c2c66..4947ee96cc62cdeae37a15f65497d7f1013dbf11 100644
--- a/drivers/mfd/max77620.c
+++ b/drivers/mfd/max77620.c
@@ -496,7 +496,7 @@ static int max77620_pm_power_off(struct sys_off_data *data)
 
 static int max77620_probe(struct i2c_client *client)
 {
-	const struct i2c_device_id *id = i2c_client_get_device_id(client);
+	const enum max77620_chip_id *id = i2c_get_match_data(client);
 	const struct regmap_config *rmap_config;
 	struct max77620_chip *chip;
 	struct regmap_irq_chip *chip_desc;
@@ -504,6 +504,9 @@ static int max77620_probe(struct i2c_client *client)
 	int n_mfd_cells;
 	int ret;
 
+	if (!id)
+		return -ENODEV;
+
 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;
@@ -519,7 +522,7 @@ static int max77620_probe(struct i2c_client *client)
 
 	chip->dev = &client->dev;
 	chip->chip_irq = client->irq;
-	chip->chip_id = (enum max77620_chip_id)id->driver_data;
+	chip->chip_id = *id;
 
 	switch (chip->chip_id) {
 	case MAX77620:
@@ -693,12 +696,27 @@ out:
 	return 0;
 }
 
+static const enum max77620_chip_id max77620_chip_ids[] = {
+	[MAX77620] = MAX77620,
+	[MAX20024] = MAX20024,
+	[MAX77663] = MAX77663,
+};
+
 static const struct i2c_device_id max77620_id[] = {
-	{"max77620", MAX77620},
-	{"max20024", MAX20024},
-	{"max77663", MAX77663},
+	{"max77620", (kernel_ulong_t)&max77620_chip_ids[MAX77620]},
+	{"max20024", (kernel_ulong_t)&max77620_chip_ids[MAX20024]},
+	{"max77663", (kernel_ulong_t)&max77620_chip_ids[MAX77663]},
 	{},
 };
+MODULE_DEVICE_TABLE(i2c, max77620_id);
+
+static const struct of_device_id max77620_of_match[] = {
+	{ .compatible = "maxim,max77620", .data = &max77620_chip_ids[MAX77620] },
+	{ .compatible = "maxim,max20024", .data = &max77620_chip_ids[MAX20024] },
+	{ .compatible = "maxim,max77663", .data = &max77620_chip_ids[MAX77663] },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max77620_of_match);
 
 static DEFINE_SIMPLE_DEV_PM_OPS(max77620_pm_ops,
 				max77620_i2c_suspend, max77620_i2c_resume);
@@ -706,6 +724,7 @@ static DEFINE_SIMPLE_DEV_PM_OPS(max77620_pm_ops,
 static struct i2c_driver max77620_driver = {
 	.driver = {
 		.name = "max77620",
+		.of_match_table = max77620_of_match,
 		.pm = pm_sleep_ptr(&max77620_pm_ops),
 	},
 	.probe = max77620_probe,

base-commit: 319633b06ff2bfc2a7a60d2cfcab2e681a343b27