linux-kernel - Re: [PATCH v3 1/2] pinctrl: qcom: Add support for i2c specific pull feature

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Message-ID: <20230209034801.owvldpyfbeerfj6x@ripper>
Date:   Wed, 8 Feb 2023 19:48:01 -0800
From:   Bjorn Andersson <andersson@...nel.org>
To:     Abel Vesa <abel.vesa@...aro.org>
Cc:     Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Neil Armstrong <neil.armstrong@...aro.org>
Subject: Re: [PATCH v3 1/2] pinctrl: qcom: Add support for i2c specific pull
 feature

On Wed, Feb 08, 2023 at 10:18:35AM +0200, Abel Vesa wrote:
> Add support for the new i2c_pull property introduced for SM8550 setting
> a I2C specific pull mode on I2C able pins. Add the bit to the SM8550
> specific driver while at it.
> 
> Co-developed-by: Neil Armstrong <neil.armstrong@...aro.org>
> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> ---
> 
> The v2 of this specific patch is here:
> https://lore.kernel.org/all/20221123152001.694546-4-abel.vesa@linaro.org/
> 
> Changes since v2:
>  * This time, this patch is sent separate w.r.t. SM8550 pinctrl driver
>  * The qcom,i2c-pull is dropped, bias-pull-up with value is used instead
>  * Default value for i2c pull up is 2.2kOhms and since SM8550 is the
>    first one to use it, we hard code it for now
>  * changed the authorship as the implementation looks entirely different now
> 
>  drivers/pinctrl/qcom/pinctrl-msm.c    | 7 +++++++
>  drivers/pinctrl/qcom/pinctrl-msm.h    | 1 +
>  drivers/pinctrl/qcom/pinctrl-sm8550.c | 1 +
>  3 files changed, 9 insertions(+)
> 
> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
> index 5142c363480a..510c964dd0f5 100644
> --- a/drivers/pinctrl/qcom/pinctrl-msm.c
> +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
> @@ -310,6 +310,8 @@ static int msm_config_reg(struct msm_pinctrl *pctrl,
>  	case PIN_CONFIG_BIAS_PULL_UP:
>  		*bit = g->pull_bit;
>  		*mask = 3;
> +		if (g->i2c_pull_bit)
> +			*mask |= BIT(g->i2c_pull_bit) >> *bit;
>  		break;
>  	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
>  		*bit = g->od_bit;
> @@ -336,6 +338,7 @@ static int msm_config_reg(struct msm_pinctrl *pctrl,
>  #define MSM_KEEPER		2
>  #define MSM_PULL_UP_NO_KEEPER	2
>  #define MSM_PULL_UP		3
> +#define MSM_I2C_STRONG_PULL_UP	2200
>  
>  static unsigned msm_regval_to_drive(u32 val)
>  {
> @@ -387,6 +390,8 @@ static int msm_config_group_get(struct pinctrl_dev *pctldev,
>  	case PIN_CONFIG_BIAS_PULL_UP:
>  		if (pctrl->soc->pull_no_keeper)
>  			arg = arg == MSM_PULL_UP_NO_KEEPER;
> +		else if (arg & BIT(g->i2c_pull_bit))
> +			arg = MSM_I2C_STRONG_PULL_UP;
>  		else
>  			arg = arg == MSM_PULL_UP;
>  		if (!arg)
> @@ -467,6 +472,8 @@ static int msm_config_group_set(struct pinctrl_dev *pctldev,
>  		case PIN_CONFIG_BIAS_PULL_UP:
>  			if (pctrl->soc->pull_no_keeper)
>  				arg = MSM_PULL_UP_NO_KEEPER;
> +			else if (g->i2c_pull_bit && arg > 1)

I would prefer that we do arg == MSM_I2C_STRONG_PULL_UP, primarily to
improve the symmetry with the getter, but also just to ensure that
someone accidentally writing bias-pull-up = <1>; gets less of a
surprise.

Looks good otherwise.

Thanks,
Bjorn

> +				arg = BIT(g->i2c_pull_bit) | MSM_PULL_UP;
>  			else
>  				arg = MSM_PULL_UP;
>  			break;
> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.h b/drivers/pinctrl/qcom/pinctrl-msm.h
> index 05a1209bf9ae..985eceda2517 100644
> --- a/drivers/pinctrl/qcom/pinctrl-msm.h
> +++ b/drivers/pinctrl/qcom/pinctrl-msm.h
> @@ -80,6 +80,7 @@ struct msm_pingroup {
>  
>  	unsigned pull_bit:5;
>  	unsigned drv_bit:5;
> +	unsigned i2c_pull_bit:5;
>  
>  	unsigned od_bit:5;
>  	unsigned egpio_enable:5;
> diff --git a/drivers/pinctrl/qcom/pinctrl-sm8550.c b/drivers/pinctrl/qcom/pinctrl-sm8550.c
> index 0b7db7d4054a..c9d038098f2c 100644
> --- a/drivers/pinctrl/qcom/pinctrl-sm8550.c
> +++ b/drivers/pinctrl/qcom/pinctrl-sm8550.c
> @@ -47,6 +47,7 @@
>  		.mux_bit = 2,			\
>  		.pull_bit = 0,			\
>  		.drv_bit = 6,			\
> +		.i2c_pull_bit = 13,		\
>  		.egpio_enable = 12,		\
>  		.egpio_present = 11,		\
>  		.oe_bit = 9,			\
> -- 
> 2.34.1
>