linux-kernel - Re: [PATCH 3/3] regulator: axp20x: add support for the AXP318W

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Message-ID: <CAGb2v67UFUAKz7tWV1b2YtANBU7a9b4KRb1SOOs=bxM4DBPwPw@mail.gmail.com>
Date: Tue, 4 Nov 2025 00:54:51 +0800
From: Chen-Yu Tsai <wens@...nel.org>
To: Andre Przywara <andre.przywara@....com>
Cc: Lee Jones <lee@...nel.org>, Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, 
	Samuel Holland <samuel@...lland.org>, Jernej Skrabec <jernej.skrabec@...il.com>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Yixun Lan <dlan@...too.org>, devicetree@...r.kernel.org, linux-sunxi@...ts.linux.dev, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] regulator: axp20x: add support for the AXP318W

On Tue, Oct 21, 2025 at 7:20 PM Andre Przywara <andre.przywara@....com> wrote:
>
> The X-Powers AXP318W is a typical PMIC from X-Powers, featuring nine
> DC/DC converters and 28 LDOs, on the regulator side.
>
> Describe the chip's voltage settings and switch registers, how the
> voltages are encoded, and connect this to the MFD device via its
> regulator ID.
> We use just "318" for the internal identifiers, for easier typing and
> less churn. If something else other than the "AXP318W" shows up, that's
> an easy change, externally visible strings carry the additional letter
> already.
>
> Signed-off-by: Andre Przywara <andre.przywara@....com>
> ---
>  drivers/regulator/axp20x-regulator.c | 170 ++++++++++++++++++++++++++-
>  include/linux/mfd/axp20x.h           |  43 +++++++
>  2 files changed, 211 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/regulator/axp20x-regulator.c b/drivers/regulator/axp20x-regulator.c
> index da891415efc0b..1576bf4178f8f 100644
> --- a/drivers/regulator/axp20x-regulator.c
> +++ b/drivers/regulator/axp20x-regulator.c
> @@ -138,6 +138,15 @@
>  #define AXP313A_DCDC_V_OUT_MASK                GENMASK(6, 0)
>  #define AXP313A_LDO_V_OUT_MASK         GENMASK(4, 0)
>
> +#define AXP318_DCDC1_V_OUT_MASK                GENMASK(4, 0)
> +#define AXP318_DCDC2_V_OUT_MASK                GENMASK(6, 0)
> +#define AXP318_LDO_V_OUT_MASK          GENMASK(4, 0)
> +#define AXP318_ELDO_V_OUT_MASK         GENMASK(5, 0)

> +#define AXP318_DCDC2_NUM_VOLTAGES      88
> +#define AXP318_DCDC6_NUM_VOLTAGES      128
> +#define AXP318_DCDC7_NUM_VOLTAGES      103
> +#define AXP318_DCDC8_NUM_VOLTAGES      119

Upon closer inspection of the helper code, these aren't actually needed.
My bad for introducing this unused field in the first place.

[...]

> +       AXP_DESC(AXP318, ELDO4, "eldo4", "eldoin", 500, 1500, 25,
> +                AXP318_ELDO4_CONTROL, AXP318_ELDO_V_OUT_MASK,
> +                AXP318_LDO_OUTPUT_CONTROL4, BIT(1)),
> +       AXP_DESC(AXP318, ELDO5, "eldo5", "eldoin", 500, 1500, 25,
> +                AXP318_ELDO5_CONTROL, AXP318_ELDO_V_OUT_MASK,
> +                AXP318_LDO_OUTPUT_CONTROL4, BIT(2)),

eldo4 and eldo5 support operating in switch mode. We can model that as
a bypass mode control. See the *bypass* fields in regulator_desc and
regulator_set_bypass_regmap() / regulator_get_bypass_regmap().

The rest check out. But also see my other reply regarding the 1.54v
threshold.


Thanks
ChenYu