Re: [PATCH v5 1/5] soc: renesas: rz-sysc: add syscon/regmap support

[Claudiu Beznea <claudiu.beznea@tuxon.dev>]

Hi, John,

On 31.03.2025 00:49, John Madieu wrote:
> The RZ/G3E system controller has various registers that control or report
> some properties specific to individual IPs. The regmap is registered as a
> syscon device to allow these IP drivers to access the registers through the
> regmap API.
> 
> As other RZ SoCs might have custom read/write callbacks or max-offsets, let's
> register a custom regmap configuration.
> 
> Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
> ---
> v1 -> v2: no changes
> v2 -> v3: no changes
> v3 -> v4: no changes
> v4 -> v5: no changes
> 
> Note for Maintainers: There is a false positive warning reported by
> checkpatch.pl on this patch patch stating that the regmap_config struct
> should be const, despite the fact it's updated in probe().
> 
>  drivers/soc/renesas/Kconfig         |  1 +
>  drivers/soc/renesas/r9a09g047-sys.c |  1 +
>  drivers/soc/renesas/rz-sysc.c       | 30 ++++++++++++++++++++++++++++-
>  drivers/soc/renesas/rz-sysc.h       |  2 ++
>  4 files changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/soc/renesas/Kconfig b/drivers/soc/renesas/Kconfig
> index 49648cf28bd2..3ffd3a4ca18d 100644
> --- a/drivers/soc/renesas/Kconfig
> +++ b/drivers/soc/renesas/Kconfig
> @@ -388,6 +388,7 @@ config RST_RCAR
>  
>  config SYSC_RZ
>  	bool "System controller for RZ SoCs" if COMPILE_TEST
> +	select MFD_SYSCON
>  
>  config SYSC_R9A08G045
>  	bool "Renesas RZ/G3S System controller support" if COMPILE_TEST
> diff --git a/drivers/soc/renesas/r9a09g047-sys.c b/drivers/soc/renesas/r9a09g047-sys.c
> index cd2eb7782cfe..5b010a519fab 100644
> --- a/drivers/soc/renesas/r9a09g047-sys.c
> +++ b/drivers/soc/renesas/r9a09g047-sys.c
> @@ -64,4 +64,5 @@ static const struct rz_sysc_soc_id_init_data rzg3e_sys_soc_id_init_data __initco
>  
>  const struct rz_sysc_init_data rzg3e_sys_init_data = {
>  	.soc_id_init_data = &rzg3e_sys_soc_id_init_data,
> +	.max_register_offset = 0x170c,
>  };
> diff --git a/drivers/soc/renesas/rz-sysc.c b/drivers/soc/renesas/rz-sysc.c
> index 1c98da37b7d1..bcbc23da954b 100644
> --- a/drivers/soc/renesas/rz-sysc.c
> +++ b/drivers/soc/renesas/rz-sysc.c
> @@ -6,8 +6,10 @@
>   */
>  
>  #include <linux/io.h>
> +#include <linux/mfd/syscon.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> +#include <linux/regmap.h>
>  #include <linux/sys_soc.h>
>  
>  #include "rz-sysc.h"
> @@ -81,6 +83,14 @@ static int rz_sysc_soc_init(struct rz_sysc *sysc, const struct of_device_id *mat
>  	return 0;
>  }
>  
> +static struct regmap_config rz_sysc_regmap = {
> +	.name = "rz_sysc_regs",
> +	.reg_bits = 32,
> +	.reg_stride = 4,
> +	.val_bits = 32,
> +	.fast_io = true,
> +};
> +
>  static const struct of_device_id rz_sysc_match[] = {
>  #ifdef CONFIG_SYSC_R9A08G045
>  	{ .compatible = "renesas,r9a08g045-sysc", .data = &rzg3s_sysc_init_data },
> @@ -97,14 +107,21 @@ MODULE_DEVICE_TABLE(of, rz_sysc_match);
>  
>  static int rz_sysc_probe(struct platform_device *pdev)
>  {
> +	const struct rz_sysc_init_data *data;
>  	const struct of_device_id *match;
>  	struct device *dev = &pdev->dev;
> +	struct regmap *regmap;
>  	struct rz_sysc *sysc;
> +	int ret;
>  
>  	match = of_match_node(rz_sysc_match, dev->of_node);
>  	if (!match)
>  		return -ENODEV;
>  
> +	data = match->data;
> +	if (!data)
> +		return -EINVAL;
> +
>  	sysc = devm_kzalloc(dev, sizeof(*sysc), GFP_KERNEL);
>  	if (!sysc)
>  		return -ENOMEM;
> @@ -114,7 +131,18 @@ static int rz_sysc_probe(struct platform_device *pdev)
>  		return PTR_ERR(sysc->base);
>  
>  	sysc->dev = dev;
> -	return rz_sysc_soc_init(sysc, match);
> +	ret = rz_sysc_soc_init(sysc, match);

The return value of rz_sysc_soc_init() is lost in case
data->max_register_offset != 0. Is there a reason for this?

> +
> +	if (data->max_register_offset) {
> +		rz_sysc_regmap.max_register = data->max_register_offset;
> +		regmap = devm_regmap_init_mmio(dev, sysc->base, &rz_sysc_regmap);
> +		if (IS_ERR(regmap))
> +			return PTR_ERR(regmap);
> +
> +		ret = of_syscon_register_regmap(dev->of_node, regmap);
> +	}
> +
> +	return ret;
>  }
>  
>  static struct platform_driver rz_sysc_driver = {
> diff --git a/drivers/soc/renesas/rz-sysc.h b/drivers/soc/renesas/rz-sysc.h
> index aa83948c5117..37a3bb2c87f8 100644
> --- a/drivers/soc/renesas/rz-sysc.h
> +++ b/drivers/soc/renesas/rz-sysc.h
> @@ -34,9 +34,11 @@ struct rz_sysc_soc_id_init_data {
>  /**
>   * struct rz_sysc_init_data - RZ SYSC initialization data
>   * @soc_id_init_data: RZ SYSC SoC ID initialization data
> + * @max_register_offset: Maximum SYSC register offset to be used by the regmap config
>   */
>  struct rz_sysc_init_data {
>  	const struct rz_sysc_soc_id_init_data *soc_id_init_data;
> +	u32 max_register_offset;
>  };
>  
>  extern const struct rz_sysc_init_data rzg3e_sys_init_data;