Re: [PATCH 2/7] pwm: rzg2l-gpt: Add info variable to struct rzg2l_gpt_chip

[Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>]

Hi Biju,
Thank you for the patch.

On Thu, Aug 14, 2025 at 07:41:06PM +0100, Biju wrote:
> From: Biju Das <biju.das.jz@bp.renesas.com>
> 
> RZ/G3E GPT IP is similar to the one found on RZ/G2L GPT, but there are
> some differences. The field width of prescalar on RZ/G3E is 4 whereas on
> RZ/G2L it is 3. Add rzg2l_gpt_info variable to handle this differences.
> The FIELD_PREP and FIELD_GET macro is giving compilation issue as the
> parameters are not build time constants. So added Non-constant mask
> variant of FIELD_GET() and FIELD_PREP().
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>

Reviewed-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>

Thanks & Regards,
Tommaso

> ---
>  drivers/pwm/pwm-rzg2l-gpt.c | 33 ++++++++++++++++++++++++++++-----
>  1 file changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-rzg2l-gpt.c b/drivers/pwm/pwm-rzg2l-gpt.c
> index f0a8531457ca..bf989defa527 100644
> --- a/drivers/pwm/pwm-rzg2l-gpt.c
> +++ b/drivers/pwm/pwm-rzg2l-gpt.c
> @@ -33,6 +33,19 @@
>  #include <linux/time.h>
>  #include <linux/units.h>
>  
> +/* Non-constant mask variant of FIELD_GET() and FIELD_PREP() */
> +#define field_get(_mask, _reg)	\
> +({\
> +	typeof(_mask) (mask) = (_mask); \
> +	(((_reg) & (mask)) >> (ffs(mask) - 1)); \
> +})
> +
> +#define field_prep(_mask, _val)	\
> +({\
> +	typeof(_mask) (mask) = (_mask); \
> +	(((_val) << (ffs(mask) - 1)) & (mask)); \
> +})
> +
>  #define RZG2L_GET_CH(hwpwm)	((hwpwm) / 2)
>  #define RZG2L_GET_CH_OFFS(ch)	(0x100 * (ch))
>  
> @@ -46,7 +59,6 @@
>  
>  #define RZG2L_GTCR_CST		BIT(0)
>  #define RZG2L_GTCR_MD		GENMASK(18, 16)
> -#define RZG2L_GTCR_TPCS		GENMASK(26, 24)
>  
>  #define RZG2L_GTCR_MD_SAW_WAVE_PWM_MODE	FIELD_PREP(RZG2L_GTCR_MD, 0)
>  
> @@ -77,9 +89,14 @@
>  #define RZG2L_MAX_SCALE_FACTOR	1024
>  #define RZG2L_MAX_TICKS		((u64)U32_MAX * RZG2L_MAX_SCALE_FACTOR)
>  
> +struct rzg2l_gpt_info {
> +	u32 gtcr_tpcs_mask;
> +};
> +
>  struct rzg2l_gpt_chip {
>  	void __iomem *mmio;
>  	struct mutex lock; /* lock to protect shared channel resources */
> +	const struct rzg2l_gpt_info *info;
>  	unsigned long rate_khz;
>  	u32 period_ticks[RZG2L_MAX_HW_CHANNELS];
>  	u32 channel_request_count[RZG2L_MAX_HW_CHANNELS];
> @@ -317,7 +334,7 @@ static int rzg2l_gpt_read_waveform(struct pwm_chip *chip,
>  
>  	if (rzg2l_gpt_is_ch_enabled(rzg2l_gpt, pwm->hwpwm)) {
>  		gtcr = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTCR(ch));
> -		wfhw->prescale = FIELD_GET(RZG2L_GTCR_TPCS, gtcr);
> +		wfhw->prescale = field_get(rzg2l_gpt->info->gtcr_tpcs_mask, gtcr);
>  		wfhw->gtpr = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTPR(ch));
>  		wfhw->gtccr = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTCCR(ch, sub_ch));
>  		if (wfhw->gtccr > wfhw->gtpr)
> @@ -354,8 +371,8 @@ static int rzg2l_gpt_write_waveform(struct pwm_chip *chip,
>  		rzg2l_gpt_write(rzg2l_gpt, RZG2L_GTUDDTYC(ch), RZG2L_GTUDDTYC_UP_COUNTING);
>  
>  		/* Select count clock */
> -		rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch), RZG2L_GTCR_TPCS,
> -				 FIELD_PREP(RZG2L_GTCR_TPCS, wfhw->prescale));
> +		rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch), rzg2l_gpt->info->gtcr_tpcs_mask,
> +				 field_prep(rzg2l_gpt->info->gtcr_tpcs_mask, wfhw->prescale));
>  
>  		/* Set period */
>  		rzg2l_gpt_write(rzg2l_gpt, RZG2L_GTPR(ch), wfhw->gtpr);
> @@ -414,6 +431,8 @@ static int rzg2l_gpt_probe(struct platform_device *pdev)
>  	if (IS_ERR(rzg2l_gpt->mmio))
>  		return PTR_ERR(rzg2l_gpt->mmio);
>  
> +	rzg2l_gpt->info = of_device_get_match_data(dev);
> +
>  	rstc = devm_reset_control_get_exclusive_deasserted(dev, NULL);
>  	if (IS_ERR(rstc))
>  		return dev_err_probe(dev, PTR_ERR(rstc), "Cannot deassert reset control\n");
> @@ -456,8 +475,12 @@ static int rzg2l_gpt_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct rzg2l_gpt_info rzg2l_data = {
> +	.gtcr_tpcs_mask = GENMASK(26, 24),
> +};
> +
>  static const struct of_device_id rzg2l_gpt_of_table[] = {
> -	{ .compatible = "renesas,rzg2l-gpt", },
> +	{ .compatible = "renesas,rzg2l-gpt", .data = &rzg2l_data },
>  	{ /* Sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(of, rzg2l_gpt_of_table);
> -- 
> 2.43.0
>