[PATCH v2 2/2] power: pmic: pca9450: Add support for reset status

[Paul Geurts]

> PCA9450 PMIC supports reading the reset status from the PWRON_STAT
> register. Bits 7-4 give indication of the PMIC reset cause:
> 
>  - PWRON (BIT7) - Power ON triggered by PMIC_ON_REQ input line,
>  - WDOGB (BIT6) - Boot after cold reset by WDOGB pin (watchdog reset),
>  - SW_RST (BIT5) - Boot after cold reset initiated by the software,
>  - PMIC_RST (BIT4) - Boot after PMIC_RST_B input line trigger.
> 
> Add support for reading reset status via the sysreset framework in a
> convenient printable format.
> 
> Signed-off-by: Primoz Fiser <primoz.fiser at norik.com>

Reviewed-by: Paul Geurts <paul.geurts at prodrive-technologies.com>

> ---
> Change in v2:
> - new patch as suggested by Paul Geurts
> 
> Link to v1: https://lore.kernel.org/all/20250716114547.1343797-1-primoz.fiser@norik.com/
> 
>  drivers/power/pmic/pca9450.c | 38 ++++++++++++++++++++++++++++++++++++
>  include/power/pca9450.h      |  5 +++++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/power/pmic/pca9450.c b/drivers/power/pmic/pca9450.c
> index abc39d0a1946..24426df1a49f 100644
> --- a/drivers/power/pmic/pca9450.c
> +++ b/drivers/power/pmic/pca9450.c
> @@ -166,8 +166,46 @@ static int pca9450_sysreset_request(struct udevice *dev, enum sysreset_t type)
>  	return -EINPROGRESS;
>  }
>  
> +int pca9450_sysreset_get_status(struct udevice *dev, char *buf, int size)
> +{
> +	const char *reason;
> +	int ret;
> +	u8 reg;
> +
> +	ret = pmic_read(dev->parent, PCA9450_PWRON_STAT, &reg, 1);
> +	if (ret)
> +		return ret;
> +
> +	switch (reg) {
> +	case PCA9450_PWRON_STAT_PWRON_MASK:
> +		reason = "PWRON";
> +		break;
> +	case PCA9450_PWRON_STAT_WDOG_MASK:
> +		reason = "WDOGB";
> +		break;
> +	case PCA9450_PWRON_STAT_SW_RST_MASK:
> +		reason = "SW_RST";
> +		break;
> +	case PCA9450_PWRON_STAT_PMIC_RST_MASK:
> +		reason = "PMIC_RST";
> +		break;
> +	default:
> +		reason = "UNKNOWN";
> +		break;
> +	}
> +
> +	ret = snprintf(buf, size, "Reset Status: %s\n", reason);
> +	if (ret < 0) {
> +		dev_err(dev, "Write reset status error (err = %d)\n", ret);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
>  static struct sysreset_ops pca9450_sysreset_ops = {
>  	.request	= pca9450_sysreset_request,
> +	.get_status	= pca9450_sysreset_get_status,
>  };
>  
>  U_BOOT_DRIVER(pca9450_sysreset) = {
> diff --git a/include/power/pca9450.h b/include/power/pca9450.h
> index 9119ef793b1f..41b7f95c0340 100644
> --- a/include/power/pca9450.h
> +++ b/include/power/pca9450.h
> @@ -75,6 +75,11 @@ enum {
>  #define PCA9450_PMIC_RESET_WDOG_B_CFG_WARM		0x40
>  #define PCA9450_PMIC_RESET_WDOG_B_CFG_COLD_LDO12	0x80
>  
> +#define PCA9450_PWRON_STAT_PWRON_MASK		0x80
> +#define PCA9450_PWRON_STAT_WDOG_MASK		0x40
> +#define PCA9450_PWRON_STAT_SW_RST_MASK		0x20
> +#define PCA9450_PWRON_STAT_PMIC_RST_MASK		0x10
> +
>  #define PCA9450_SW_RST_COLD_RST		0x14
>  
>  #endif
> -- 
> 2.34.1

br,
Paul