linux-kernel - Re: [PATCH] mfd: axp20x: Skip PEK on AXP313A/AXP323 if no interrupt line is available

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Message-ID: <20250701110150.GJ10134@google.com>
Date: Tue, 1 Jul 2025 12:01:50 +0100
From: Lee Jones <lee@...nel.org>
To: Chen-Yu Tsai <wens@...nel.org>
Cc: Chen-Yu Tsai <wens@...e.org>, linux-sunxi@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Andre Przywara <andre.przywara@....com>,
	Chris Morgan <macroalpha82@...il.com>,
	Vasily Khoruzhick <anarsoul@...il.com>
Subject: Re: [PATCH] mfd: axp20x: Skip PEK on AXP313A/AXP323 if no interrupt
 line is available

On Mon, 30 Jun 2025, Chen-Yu Tsai wrote:

> From: Chen-Yu Tsai <wens@...e.org>
> 
> Originally an explicit ID for the AXP313/AXP323 regulator was set to
> avoid a conflict with the primary AXP717 PMIC on Allwinner A523 family
> boards.
> 
> This didn't entirely work since on some or all of these boards, the
> interrupt line on this secondary PMIC was left unconnected, and thus
> the driver would fall back to the generic "no interrupt; only regulators"
> case, which didn't have the explicit ID set, thus undoing the intended
> fix.
> 
> Explicitly exclude the PEK cell in the no IRQ case for the
> AXP313/AXP323, instead of using the generic fallback.
> 
> Fixes: 249abf9b1e25 ("mfd: axp20x: Set explicit ID for AXP313 regulator")
> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
> ---
> The other option would be to move the explicit ID to the generic
> fallback case instead. This is really only visible in sysfs and the
> kernel logs, so probably not that important.
> ---
>  drivers/mfd/axp20x.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index 25c639b348cd..8877482a95a1 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -1055,6 +1055,7 @@ static const struct mfd_cell axp152_cells[] = {
>  static struct mfd_cell axp313a_cells[] = {
>  	/* AXP323 is sometimes paired with AXP717 as sub-PMIC */
>  	MFD_CELL_BASIC("axp20x-regulator", NULL, NULL, 0, 1),
> +	/* Keep PEK as last entry for exclusion in no-irq cases */
>  	MFD_CELL_RES("axp313a-pek", axp313a_pek_resources),
>  };
>  
> @@ -1306,12 +1307,18 @@ int axp20x_match_device(struct axp20x_dev *axp20x)
>  		axp20x->irq_flags = IRQF_TRIGGER_LOW;
>  		break;
>  	case AXP313A_ID:
> +		/* Exclude PEK if no IRQ is available */
> +		nr_cells_no_irq = ARRAY_SIZE(axp313a_cells) - 1;

This is too fragile.  Please fine another way to achieve your goal.

> +		cells_no_irq = axp313a_cells;
>  		axp20x->nr_cells = ARRAY_SIZE(axp313a_cells);
>  		axp20x->cells = axp313a_cells;
>  		axp20x->regmap_cfg = &axp313a_regmap_config;
>  		axp20x->regmap_irq_chip = &axp313a_regmap_irq_chip;
>  		break;
>  	case AXP323_ID:
> +		/* Exclude PEK if no IRQ is available */
> +		nr_cells_no_irq = ARRAY_SIZE(axp313a_cells) - 1;
> +		cells_no_irq = axp313a_cells;
>  		axp20x->nr_cells = ARRAY_SIZE(axp313a_cells);
>  		axp20x->cells = axp313a_cells;
>  		axp20x->regmap_cfg = &axp323_regmap_config;
> -- 
> 2.39.5
> 

-- 
Lee Jones [李琼斯]