Re: [PATCH] mfd: tps65219: Implement LOCK register handling for TPS65214

[Andrew Davis <afd@ti.com>]

On 11/5/25 11:47 AM, Kory Maincent wrote:
> From: "Kory Maincent (TI.com)" <kory.maincent@bootlin.com>
> 
> The TPS65214 PMIC variant has a LOCK_REG register that prevents writes to
> nearly all registers.
> 
> Implement custom regmap operations that automatically unlock before writes
> and re-lock afterwards for TPS65214, while leaving other chip variants
> unaffected.
> 
> The implementation follows the regmap-i2c design pattern.
> 
> Signed-off-by: Kory Maincent (TI.com) <kory.maincent@bootlin.com>
> ---
>   drivers/mfd/tps65219.c       | 53 +++++++++++++++++++++++++++++++++++-
>   include/linux/mfd/tps65219.h |  3 ++
>   2 files changed, 55 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/tps65219.c b/drivers/mfd/tps65219.c
> index 65a952555218d..1d8a06afb1048 100644
> --- a/drivers/mfd/tps65219.c
> +++ b/drivers/mfd/tps65219.c
> @@ -473,6 +473,55 @@ static const struct tps65219_chip_data chip_info_table[] = {
>   	},
>   };
>   
> +static int tps65219_reg_write(void *context, unsigned int reg, unsigned int val)
> +{
> +	struct i2c_client *i2c = context;
> +	struct tps65219 *tps;
> +	int ret;
> +
> +	if (val > 0xff || reg > 0xff)
> +		return -EINVAL;
> +
> +	tps = i2c_get_clientdata(i2c);
> +	if (tps->chip_id == TPS65214) {
> +		ret = i2c_smbus_write_byte_data(i2c, TPS65214_REG_LOCK,
> +						TPS65214_LOCK_ACCESS_CMD);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = i2c_smbus_write_byte_data(i2c, reg, val);
> +	if (ret)
> +		return ret;
> +
> +	if (tps->chip_id == TPS65214)
> +		return i2c_smbus_write_byte_data(i2c, TPS65214_REG_LOCK, 0);
> +
> +	return 0;
> +}
> +
> +static int tps65219_reg_read(void *context, unsigned int reg, unsigned int *val)
> +{
> +	struct i2c_client *i2c = context;
> +	int ret;
> +
> +	if (reg > 0xff)
> +		return -EINVAL;
> +
> +	ret = i2c_smbus_read_byte_data(i2c, reg);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = ret;
> +
> +	return 0;
> +}
> +
> +static const struct regmap_bus tps65219_regmap_bus = {
> +	.reg_write = tps65219_reg_write,
> +	.reg_read = tps65219_reg_read,
> +};
> +
>   static int tps65219_probe(struct i2c_client *client)
>   {
>   	struct tps65219 *tps;
> @@ -490,8 +539,10 @@ static int tps65219_probe(struct i2c_client *client)
>   	tps->dev = &client->dev;
>   	chip_id = (uintptr_t)i2c_get_match_data(client);
>   	pmic = &chip_info_table[chip_id];
> +	tps->chip_id = chip_id;
>   
> -	tps->regmap = devm_regmap_init_i2c(client, &tps65219_regmap_config);
> +	tps->regmap = devm_regmap_init(&client->dev, &tps65219_regmap_bus, client,
> +				       &tps65219_regmap_config);

Why not do the (tps->chip_id == TPS65214) check here and only setup the
special regmap_bus for the TPS65214. Then you don't need to do the checks
every time reg_write is called.

It also means you don't need to store chip_id in the device instance data.

Andrew

>   	if (IS_ERR(tps->regmap)) {
>   		ret = PTR_ERR(tps->regmap);
>   		dev_err(tps->dev, "Failed to allocate register map: %d\n", ret);
> diff --git a/include/linux/mfd/tps65219.h b/include/linux/mfd/tps65219.h
> index 55234e771ba73..53e53cbc5c76f 100644
> --- a/include/linux/mfd/tps65219.h
> +++ b/include/linux/mfd/tps65219.h
> @@ -149,6 +149,8 @@ enum pmic_id {
>   #define TPS65215_ENABLE_LDO2_EN_MASK                    BIT(5)
>   #define TPS65214_ENABLE_LDO1_EN_MASK			BIT(5)
>   #define TPS65219_ENABLE_LDO4_EN_MASK			BIT(6)
> +/* Register Lock */
> +#define TPS65214_LOCK_ACCESS_CMD			0x5a
>   /* power ON-OFF sequence slot */
>   #define TPS65219_BUCKS_LDOS_SEQUENCE_OFF_SLOT_MASK	GENMASK(3, 0)
>   #define TPS65219_BUCKS_LDOS_SEQUENCE_ON_SLOT_MASK	GENMASK(7, 4)
> @@ -444,6 +446,7 @@ struct tps65219 {
>   	struct regmap *regmap;
>   
>   	struct regmap_irq_chip_data *irq_data;
> +	enum pmic_id chip_id;
>   };
>   
>   #endif /* MFD_TPS65219_H */