linux-kernel - Re: [PATCH v2 07/12] mfd: sec: store hardware revision in sec_pmic

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Message-ID: <f6d1340062448cf52e4c034d250524e030877898.camel@linaro.org>
Date: Wed, 04 Feb 2026 14:17:35 +0000
From: André Draszik <andre.draszik@...aro.org>
To: Kaustabh Chakraborty <kauschluss@...root.org>, Lee Jones
 <lee@...nel.org>,  Pavel Machek <pavel@...nel.org>, Rob Herring
 <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,  Conor Dooley
 <conor+dt@...nel.org>, MyungJoo Ham <myungjoo.ham@...sung.com>, Chanwoo
 Choi	 <cw00.choi@...sung.com>, Sebastian Reichel <sre@...nel.org>,
 Krzysztof Kozlowski <krzk@...nel.org>, Alexandre Belloni
 <alexandre.belloni@...tlin.com>, Jonathan Corbet	 <corbet@....net>, Shuah
 Khan <skhan@...uxfoundation.org>
Cc: linux-leds@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, 
	linux-samsung-soc@...r.kernel.org, linux-rtc@...r.kernel.org, 
	linux-doc@...r.kernel.org
Subject: Re: [PATCH v2 07/12] mfd: sec: store hardware revision in
 sec_pmic_dev and add S2MU005 support

Hi Kaustabh,

On Mon, 2026-01-26 at 00:37 +0530, Kaustabh Chakraborty wrote:
> The device revision matters in cases when in some PMICs, the correct
> register offsets very in different revisions. Instead of just debug

s/very/vary

> printing the value, store it in the driver data struct.

Please mention that you're not doing that for s2mpg1x, though.

> 
> Unlike other devices, S2MU005 has its hardware revision ID in register
> offset 0x73. Allow handling different devices and add support for S2MU005.
> 
> Signed-off-by: Kaustabh Chakraborty <kauschluss@...root.org>
> ---
>  drivers/mfd/sec-common.c         | 41 ++++++++++++++++++++++++++++++----------
>  include/linux/mfd/samsung/core.h |  1 +
>  2 files changed, 32 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mfd/sec-common.c b/drivers/mfd/sec-common.c
> index bc2a1f2c6dc7a..069a1ba9aa1f1 100644
> --- a/drivers/mfd/sec-common.c
> +++ b/drivers/mfd/sec-common.c
> @@ -16,6 +16,7 @@
>  #include <linux/mfd/samsung/irq.h>
>  #include <linux/mfd/samsung/s2mps11.h>
>  #include <linux/mfd/samsung/s2mps13.h>
> +#include <linux/mfd/samsung/s2mu005.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/pm.h>
> @@ -111,17 +112,38 @@ static const struct mfd_cell s2mu005_devs[] = {
>  	MFD_CELL_OF("s2mu005-rgb", NULL, NULL, 0, 0, "samsung,s2mu005-rgb"),
>  };
>  
> -static void sec_pmic_dump_rev(struct sec_pmic_dev *sec_pmic)
> +static int sec_pmic_store_rev(struct sec_pmic_dev *sec_pmic)
>  {
> -	unsigned int val;
> +	unsigned int reg, mask, shift;
> +	int ret;
>  
> -	/* For s2mpg1x, the revision is in a different regmap */
> -	if (sec_pmic->device_type == S2MPG10)
> -		return;
> +	switch (sec_pmic->device_type) {
> +	case S2MPG10:
> +		/* For s2mpg1x, the revision is in a different regmap */
> +		return 0;
> +	case S2MU005:
> +		reg = S2MU005_REG_ID;
> +		mask = S2MU005_ID_MASK;
> +		shift = S2MU005_ID_SHIFT;
> +		break;
> +	default:
> +		/* For other device types, the REG_ID is always the first register. */
> +		reg = S2MPS11_REG_ID;
> +		mask = ~0;
> +		shift = 0;
> +	}
> +
> +	ret = regmap_read(sec_pmic->regmap_pmic, reg, &sec_pmic->revision);
> +	if (ret) {
> +		dev_err(sec_pmic->dev, "Failed to read PMIC revision (%d)\n", ret);
> +		return ret;
> +	}
> +
> +	sec_pmic->revision &= mask;
> +	sec_pmic->revision >>= shift;
>  
> -	/* For each device type, the REG_ID is always the first register */
> -	if (!regmap_read(sec_pmic->regmap_pmic, S2MPS11_REG_ID, &val))
> -		dev_dbg(sec_pmic->dev, "Revision: 0x%x\n", val);
> +	dev_dbg(sec_pmic->dev, "Revision: 0x%x\n", sec_pmic->revision);
> +	return 0;
>  }
>  
>  static void sec_pmic_configure(struct sec_pmic_dev *sec_pmic)
> @@ -262,9 +284,8 @@ int sec_pmic_probe(struct device *dev, int device_type, unsigned int irq,
>  		return ret;
>  
>  	sec_pmic_configure(sec_pmic);
> -	sec_pmic_dump_rev(sec_pmic);
>  
> -	return ret;
> +	return sec_pmic_store_rev(sec_pmic);
>  }
>  EXPORT_SYMBOL_GPL(sec_pmic_probe);
>  
> diff --git a/include/linux/mfd/samsung/core.h b/include/linux/mfd/samsung/core.h
> index 43e0c5e55f5d3..56aa33d7e3d60 100644
> --- a/include/linux/mfd/samsung/core.h
> +++ b/include/linux/mfd/samsung/core.h
> @@ -70,6 +70,7 @@ struct sec_pmic_dev {
>  
>  	int device_type;
>  	int irq;
> +	unsigned int revision;

kerneldoc needs to be updated.

Given the LED driver is the only driver & device so far which needs the
PMIC revision, maybe for now that driver could determine the revision
itself instead of adding this new member for everybody?

Cheers,
Andre'

>  };
>  
>  struct sec_platform_data {