linux-kernel - Re: [PATCH v4 5/8] reset: imx8mp-audiomix: Switch to using regmap API

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Message-ID: <5922965da5a0dc1ff976bcbc1efcc9a7baa32934.camel@pengutronix.de>
Date: Wed, 05 Nov 2025 16:10:41 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Laurentiu Mihalcea <laurentiumihalcea111@...il.com>, Abel Vesa	
 <abelvesa@...nel.org>, Michael Turquette <mturquette@...libre.com>, Stephen
 Boyd <sboyd@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor
 Dooley	 <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>, Fabio
 Estevam	 <festevam@...il.com>, Daniel Baluta <daniel.baluta@....com>,
 Shengjiu Wang	 <shengjiu.wang@....com>, Frank Li <Frank.Li@....com>
Cc: linux-clk@...r.kernel.org, imx@...ts.linux.dev,
 devicetree@...r.kernel.org, 	linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org,  Pengutronix Kernel Team	
 <kernel@...gutronix.de>
Subject: Re: [PATCH v4 5/8] reset: imx8mp-audiomix: Switch to using regmap
 API

On Di, 2025-11-04 at 04:02 -0800, Laurentiu Mihalcea wrote:
> From: Laurentiu Mihalcea <laurentiu.mihalcea@....com>
> 
> Switch to using the regmap API to allow performing register operations
> under the same lock. This is needed for cases such as i.MX8ULP's SIM LPAV
> where clock gating, reset control and MUX-ing is performed via the same
> register (i.e. SYSCTRL0) and different subsystem APIs.
> 
> Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@....com>
> ---
>  drivers/reset/reset-imx8mp-audiomix.c | 93 +++++++++++++++++----------
>  1 file changed, 58 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/reset/reset-imx8mp-audiomix.c b/drivers/reset/reset-imx8mp-audiomix.c
> index e9643365a62c..18a7f68aa59f 100644
> --- a/drivers/reset/reset-imx8mp-audiomix.c
> +++ b/drivers/reset/reset-imx8mp-audiomix.c
> @@ -11,6 +11,7 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_address.h>
> +#include <linux/regmap.h>
>  #include <linux/reset-controller.h>
>  
>  #define IMX8MP_AUDIOMIX_EARC_RESET_OFFSET	0x200
> @@ -42,8 +43,7 @@ static const struct imx8mp_reset_map reset_map[] = {
>  
>  struct imx8mp_audiomix_reset {
>  	struct reset_controller_dev rcdev;
> -	spinlock_t lock; /* protect register read-modify-write cycle */
> -	void __iomem *base;
> +	struct regmap *regmap;
>  };
>  
>  static struct imx8mp_audiomix_reset *to_imx8mp_audiomix_reset(struct reset_controller_dev *rcdev)
> @@ -55,26 +55,15 @@ static int imx8mp_audiomix_update(struct reset_controller_dev *rcdev,
>  				  unsigned long id, bool assert)
>  {
>  	struct imx8mp_audiomix_reset *priv = to_imx8mp_audiomix_reset(rcdev);
> -	void __iomem *reg_addr = priv->base;
> -	unsigned int mask, offset, active_low;
> -	unsigned long reg, flags;
> +	unsigned int mask, offset, active_low, shift, val;
>  
>  	mask = reset_map[id].mask;
>  	offset = reset_map[id].offset;
>  	active_low = reset_map[id].active_low;
> +	shift = ffs(mask) - 1;
> +	val = (active_low ^ assert) << shift;

If you store the bit offset in the reset map, this can become

	mask = BIT(reset_map[id].bit);
	/* ... */
	val = (active_low ^ assert) << reset_map[id].bit;
 

regards
Philipp