linux-kernel - Re: [PATCH v3 1/2] mfd: tps65219: Implement LOCK register handling for TPS65214

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Message-ID: <20251112135203.4a4c4c85@kmaincent-XPS-13-7390>
Date: Wed, 12 Nov 2025 13:52:03 +0100
From: Kory Maincent <kory.maincent@...tlin.com>
To: Aaro Koskinen <aaro.koskinen@....fi>, Andreas Kemnade
 <andreas@...nade.info>, Kevin Hilman <khilman@...libre.com>, Roger Quadros
 <rogerq@...nel.org>, Tony Lindgren <tony@...mide.com>, Lee Jones
 <lee@...nel.org>, Shree Ramamoorthy <s-ramamoorthy@...com>, Rob Herring
 <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>
Cc: Andrew Davis <afd@...com>, Bajjuri Praneeth <praneeth@...com>, Thomas
 Petazzoni <thomas.petazzoni@...tlin.com>, linux-omap@...r.kernel.org,
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
 stable@...r.kernel.org
Subject: Re: [PATCH v3 1/2] mfd: tps65219: Implement LOCK register handling
 for TPS65214

On Wed, 12 Nov 2025 10:45:24 +0100
"Kory Maincent (TI.com)" <kory.maincent@...tlin.com> wrote:

> 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.

After some thought and internal discussions, I think it is better to unlock the
registers only one time in the probe instead of adding burden in each regmap
write. I will rewrite this patch.
Shree I will remove your reviewed-by due to the change.

pw-bot: cr

> 
> Cc: stable@...r.kernel.org
> Fixes: 7947219ab1a2d ("mfd: tps65219: Add support for TI TPS65214 PMIC")
> Reviewed-by: Shree Ramamoorthy <s-ramamoorthy@...com>
> Signed-off-by: Kory Maincent (TI.com) <kory.maincent@...tlin.com>
> ---
> 
> Changes in v3:
> - Removed unused variable.
> 
> Changes in v2:
> - Setup a custom regmap_bus only for the TPS65214 instead of checking
>   the chip_id every time reg_write is called.
> ---
>  drivers/mfd/tps65219.c       | 49
> +++++++++++++++++++++++++++++++++++++++++++- include/linux/mfd/tps65219.h |
> 2 ++ 2 files changed, 50 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/tps65219.c b/drivers/mfd/tps65219.c
> index 65a952555218d..d31e808faab1f 100644
> --- a/drivers/mfd/tps65219.c
> +++ b/drivers/mfd/tps65219.c
> @@ -473,6 +473,48 @@ static const struct tps65219_chip_data chip_info_table[]
> = { },
>  };
>  
> +static int tps65214_reg_write(void *context, unsigned int reg, unsigned int
> val) +{
> +	struct i2c_client *i2c = context;
> +	int ret;
> +
> +	if (val > 0xff || reg > 0xff)
> +		return -EINVAL;
> +
> +	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;
> +
> +	return i2c_smbus_write_byte_data(i2c, TPS65214_REG_LOCK, 0);
> +}
> +
> +static int tps65214_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 tps65214_regmap_bus = {
> +	.reg_write = tps65214_reg_write,
> +	.reg_read = tps65214_reg_read,
> +};
> +
>  static int tps65219_probe(struct i2c_client *client)
>  {
>  	struct tps65219 *tps;
> @@ -491,7 +533,12 @@ static int tps65219_probe(struct i2c_client *client)
>  	chip_id = (uintptr_t)i2c_get_match_data(client);
>  	pmic = &chip_info_table[chip_id];
>  
> -	tps->regmap = devm_regmap_init_i2c(client, &tps65219_regmap_config);
> +	if (chip_id == TPS65214)
> +		tps->regmap = devm_regmap_init(&client->dev,
> +					       &tps65214_regmap_bus, client,
> +					       &tps65219_regmap_config);
> +	else
> +		tps->regmap = devm_regmap_init_i2c(client,
> &tps65219_regmap_config); 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..198ee319dd1db 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)
> 



-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com