linux-kernel - Re: [PATCH v1 2/7] nvmem: qcom-spmi-sdam: Migrate to devm_spmi_subdevice_alloc_and

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Message-ID: <e724e6a2-21a8-436a-8809-ce73c0afa433@linaro.org>
Date: Mon, 21 Jul 2025 12:44:26 +0200
From: Casey Connolly <casey.connolly@...aro.org>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 sboyd@...nel.org
Cc: jic23@...nel.org, dlechner@...libre.com, nuno.sa@...log.com,
 andy@...nel.org, arnd@...db.de, gregkh@...uxfoundation.org,
 srini@...nel.org, vkoul@...nel.org, kishon@...nel.org, sre@...nel.org,
 krzysztof.kozlowski@...aro.org, u.kleine-koenig@...libre.com,
 linux-arm-msm@...r.kernel.org, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-phy@...ts.infradead.org,
 linux-pm@...r.kernel.org, kernel@...labora.com, wenst@...omium.org
Subject: Re: [PATCH v1 2/7] nvmem: qcom-spmi-sdam: Migrate to
 devm_spmi_subdevice_alloc_and_add()

Hi Angelo,

On 21/07/2025 09:55, AngeloGioacchino Del Regno wrote:
> Some Qualcomm PMICs integrate a SDAM device, internally located in
> a specific address range reachable through SPMI communication.
> 
> Instead of using the parent SPMI device (the main PMIC) as a kind
> of syscon in this driver, register a new SPMI sub-device for SDAM
> and initialize its own regmap with this sub-device's specific base
> address, retrieved from the devicetree.
> 
> This allows to stop manually adding the register base address to
> every R/W call in this driver, as this can be, and is now, handled
> by the regmap API instead.

This is honestly a really nice improvement :D>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> ---
>  drivers/nvmem/qcom-spmi-sdam.c | 41 +++++++++++++++++++++++++---------
>  1 file changed, 30 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/nvmem/qcom-spmi-sdam.c b/drivers/nvmem/qcom-spmi-sdam.c
> index 4f1cca6eab71..1b80e8563a33 100644
> --- a/drivers/nvmem/qcom-spmi-sdam.c
> +++ b/drivers/nvmem/qcom-spmi-sdam.c
> @@ -9,6 +9,7 @@
>  #include <linux/nvmem-provider.h>
>  #include <linux/platform_device.h>
>  #include <linux/regmap.h>
> +#include <linux/spmi.h>
>  
>  #define SDAM_MEM_START			0x40
>  #define REGISTER_MAP_ID			0x40
> @@ -20,7 +21,6 @@
>  struct sdam_chip {
>  	struct regmap			*regmap;
>  	struct nvmem_config		sdam_config;
> -	unsigned int			base;
>  	unsigned int			size;
>  };
>  
> @@ -73,7 +73,7 @@ static int sdam_read(void *priv, unsigned int offset, void *val,
>  		return -EINVAL;
>  	}
>  
> -	rc = regmap_bulk_read(sdam->regmap, sdam->base + offset, val, bytes);
> +	rc = regmap_bulk_read(sdam->regmap, offset, val, bytes);
>  	if (rc < 0)
>  		dev_err(dev, "Failed to read SDAM offset %#x len=%zd, rc=%d\n",
>  						offset, bytes, rc);
> @@ -100,7 +100,7 @@ static int sdam_write(void *priv, unsigned int offset, void *val,
>  		return -EINVAL;
>  	}
>  
> -	rc = regmap_bulk_write(sdam->regmap, sdam->base + offset, val, bytes);
> +	rc = regmap_bulk_write(sdam->regmap, offset, val, bytes);
>  	if (rc < 0)
>  		dev_err(dev, "Failed to write SDAM offset %#x len=%zd, rc=%d\n",
>  						offset, bytes, rc);
> @@ -110,28 +110,47 @@ static int sdam_write(void *priv, unsigned int offset, void *val,
>  
>  static int sdam_probe(struct platform_device *pdev)
>  {
> +	struct regmap_config sdam_regmap_config = {
> +		.reg_bits = 16,
> +		.val_bits = 16,

I believe registers are 8 bits wide, at least on Qualcomm platforms.

Kind regards,
-- 
// Casey (she/her)