linux-kernel - Re: [PATCH 07/17] mfd: sec-common: Instantiate s2mpg10 bucks and ldos separately

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Message-ID: <20250613141902.GI897353@google.com>
Date: Fri, 13 Jun 2025 15:19:02 +0100
From: Lee Jones <lee@...nel.org>
To: André Draszik <andre.draszik@...aro.org>
Cc: Tudor Ambarus <tudor.ambarus@...aro.org>, Rob Herring <robh@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Krzysztof Kozlowski <krzk@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>,
	Peter Griffin <peter.griffin@...aro.org>,
	Will McVicker <willmcvicker@...gle.com>, kernel-team@...roid.com,
	linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	devicetree@...r.kernel.org, linux-gpio@...r.kernel.org
Subject: Re: [PATCH 07/17] mfd: sec-common: Instantiate s2mpg10 bucks and
 ldos separately

On Wed, 04 Jun 2025, André Draszik wrote:

> Bucks can conceivably be used as supplies for LDOs, which means we need
> to instantiate them separately from each other so that the supply-
> consumer links can be resolved successfully at probe time.
> 
> By doing so, the kernel will defer and retry instantiating the LDOs
> once BUCKs have been created while without this change, it can be
> impossible to mark BUCKs as LDO supplies. This becomes particularly
> an issue with the upcoming support for the S2MPG11 PMIC, where
> typically certain S2MP10/11 buck rails supply certain S2MP11/10 LDO
> rails.
> 
> The platform_device's ::id field is used to inform the regulator driver
> which type of regulators (buck or ldo) to instantiate.

I'm confused.

There is nothing that differentiates the two, so why do you need to?

> Signed-off-by: André Draszik <andre.draszik@...aro.org>
> ---
>  drivers/mfd/sec-common.c            | 4 +++-
>  include/linux/mfd/samsung/s2mpg10.h | 5 +++++
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/sec-common.c b/drivers/mfd/sec-common.c
> index 42d55e70e34c8d7cd68cddaecc88017e259365b4..8a1694c6ed8708397a51ebd4a49c22387d7e3495 100644
> --- a/drivers/mfd/sec-common.c
> +++ b/drivers/mfd/sec-common.c
> @@ -14,6 +14,7 @@
>  #include <linux/mfd/core.h>
>  #include <linux/mfd/samsung/core.h>
>  #include <linux/mfd/samsung/irq.h>
> +#include <linux/mfd/samsung/s2mpg10.h>
>  #include <linux/mfd/samsung/s2mps11.h>
>  #include <linux/mfd/samsung/s2mps13.h>
>  #include <linux/module.h>
> @@ -35,7 +36,8 @@ static const struct mfd_cell s2dos05_devs[] = {
>  
>  static const struct mfd_cell s2mpg10_devs[] = {
>  	MFD_CELL_NAME("s2mpg10-meter"),
> -	MFD_CELL_NAME("s2mpg10-regulator"),
> +	MFD_CELL_BASIC("s2mpg10-regulator", NULL, NULL, 0, S2MPG10_REGULATOR_CELL_ID_BUCKS),
> +	MFD_CELL_BASIC("s2mpg10-regulator", NULL, NULL, 0, S2MPG10_REGULATOR_CELL_ID_LDOS),
>  	MFD_CELL_NAME("s2mpg10-rtc"),
>  	MFD_CELL_OF("s2mpg10-clk", NULL, NULL, 0, 0, "samsung,s2mpg10-clk"),
>  	MFD_CELL_OF("s2mpg10-gpio", NULL, NULL, 0, 0, "samsung,s2mpg10-gpio"),
> diff --git a/include/linux/mfd/samsung/s2mpg10.h b/include/linux/mfd/samsung/s2mpg10.h
> index 9f5919b89a3c286bf1cd6b3ef0e74bc993bff01a..3e8bc65078472518c5e77f8bd199ee403eda18ea 100644
> --- a/include/linux/mfd/samsung/s2mpg10.h
> +++ b/include/linux/mfd/samsung/s2mpg10.h
> @@ -8,6 +8,11 @@
>  #ifndef __LINUX_MFD_S2MPG10_H
>  #define __LINUX_MFD_S2MPG10_H
>  
> +enum s2mpg10_regulator_mfd_cell_id {
> +	S2MPG10_REGULATOR_CELL_ID_BUCKS = 1,
> +	S2MPG10_REGULATOR_CELL_ID_LDOS = 2,
> +};
> +
>  /* Common registers (type 0x000) */
>  enum s2mpg10_common_reg {
>  	S2MPG10_COMMON_CHIPID,
> 
> -- 
> 2.49.0.1204.g71687c7c1d-goog
> 

-- 
Lee Jones [李琼斯]