Re: [PATCH v3 2/5] pinctrl: st: Enhance the controller to manage unavailable registers

[Lee Jones <lee.jones@linaro.org>]

> From: Giuseppe Cavallaro <peppe.cavallaro@st.com>
> 
> This patch adds a new logic inside the st pinctrl to manage
> an unsupported scenario: some sysconfig are not available!
> 
> This is the case of STiH407 where, although documented, the
> following registers from SYSCFG_FLASH have been removed from the SoC.
> 
> SYSTEM_CONFIG3040
>    Output Enable pad control for all PIO Alternate Functions
> and
> SYSTEM_ CONFIG3050
>    Pull Up pad control for all PIO Alternate Functions
> 
> Without managing this condition an imprecise external abort
> will be detect.
> 
> To do this the patch also reviews the st_parse_syscfgs
> and other routines to manipulate the registers only if
> actually available.
> In any case, for example the st_parse_syscfgs detected
> an error condition but no action was made in the
> st_pctl_probe_dt.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
> Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>

These two SOBs need reordering.

> ---
>  drivers/pinctrl/pinctrl-st.c | 106 +++++++++++++++++++++++++------------------
>  1 file changed, 61 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
> index 9fb66aa..1721611 100644
> --- a/drivers/pinctrl/pinctrl-st.c
> +++ b/drivers/pinctrl/pinctrl-st.c
> @@ -410,25 +410,27 @@ static void st_pinconf_set_config(struct st_pio_control *pc,
>  	unsigned int oe_value, pu_value, od_value;
>  	unsigned long mask = BIT(pin);
>  
> -	regmap_field_read(output_enable, &oe_value);
> -	regmap_field_read(pull_up, &pu_value);
> -	regmap_field_read(open_drain, &od_value);
> -
> -	/* Clear old values */
> -	oe_value &= ~mask;
> -	pu_value &= ~mask;
> -	od_value &= ~mask;
> -
> -	if (config & ST_PINCONF_OE)
> -		oe_value |= mask;
> -	if (config & ST_PINCONF_PU)
> -		pu_value |= mask;
> -	if (config & ST_PINCONF_OD)
> -		od_value |= mask;
> -
> -	regmap_field_write(output_enable, oe_value);
> -	regmap_field_write(pull_up, pu_value);
> -	regmap_field_write(open_drain, od_value);
> +	if (output_enable) {
> +		regmap_field_read(output_enable, &oe_value);
> +		oe_value &= ~mask;
> +		if (config & ST_PINCONF_OE)
> +			oe_value |= mask;
> +		regmap_field_write(output_enable, oe_value);
> +	}
> +	if (pull_up) {
> +		regmap_field_read(pull_up, &pu_value);
> +		pu_value &= ~mask;
> +		if (config & ST_PINCONF_PU)
> +			pu_value |= mask;
> +		regmap_field_write(pull_up, pu_value);
> +	}
> +	if (open_drain) {
> +		regmap_field_read(open_drain, &od_value);
> +		od_value &= ~mask;
> +		if (config & ST_PINCONF_OD)
> +			od_value |= mask;
> +		regmap_field_write(open_drain, od_value);
> +	}

Nice change.

Nit: For consistency with the changes below, please consider placing
new lines between the 3 outer checks.

>  }
>  

<snip>

> -static void st_pinconf_get_direction(struct st_pio_control *pc,
> -	int pin, unsigned long *config)
> +static void st_pinconf_get_direction(struct st_pio_control *pc, int pin,
> +				     unsigned long *config)

Unrelated change?

>  {
>  	unsigned int oe_value, pu_value, od_value;

Is it worth checking for (!config) here?

> -	regmap_field_read(pc->oe, &oe_value);
> -	regmap_field_read(pc->pu, &pu_value);
> -	regmap_field_read(pc->od, &od_value);
> +	if (pc->oe) {
> +		regmap_field_read(pc->oe, &oe_value);
> +		if (oe_value & BIT(pin))
> +			ST_PINCONF_PACK_OE(*config);
> +	}
>  
> -	if (oe_value & BIT(pin))
> -		ST_PINCONF_PACK_OE(*config);
> -	if (pu_value & BIT(pin))
> -		ST_PINCONF_PACK_PU(*config);
> -	if (od_value & BIT(pin))
> -		ST_PINCONF_PACK_OD(*config);
> +	if (pc->pu) {
> +		regmap_field_read(pc->pu, &pu_value);
> +		if (pu_value & BIT(pin))
> +			ST_PINCONF_PACK_PU(*config);
> +	}
>  
> +	if (pc->od) {
> +		regmap_field_read(pc->od, &od_value);
> +		if (od_value & BIT(pin))
> +			ST_PINCONF_PACK_OD(*config);
> +	}
>  }

Nice.

>  static int st_pinconf_get_retime_packed(struct st_pinctrl *info,
> @@ -1105,8 +1116,21 @@ static int st_pctl_dt_setup_retime(struct st_pinctrl *info,
>  	return -EINVAL;
>  }
>  
> -static int st_parse_syscfgs(struct st_pinctrl *info,
> -		int bank, struct device_node *np)
> +
> +static struct regmap_field *st_pc_get_value(struct device *dev,
> +					    struct regmap *regmap, int bank,
> +					    int data, int lsb, int msb)
> +{
> +	struct reg_field reg = REG_FIELD((data + bank) * 4, lsb, msb);
> +
> +	if (data < 0)
> +		return NULL;

What happens is data < 0 and it's used in REG_FIELD?

Would it make more sense to make this check before calling REG_FIELD?

> +	return devm_regmap_field_alloc(dev, regmap, reg);
> +}
> +
> +static void st_parse_syscfgs(struct st_pinctrl *info, int bank,
> +			     struct device_node *np)
>  {
>  	const struct st_pctl_data *data = info->data;
>  	/**
> @@ -1116,29 +1140,21 @@ static int st_parse_syscfgs(struct st_pinctrl *info,
>  	 */
>  	int lsb = (bank%4) * ST_GPIO_PINS_PER_BANK;
>  	int msb = lsb + ST_GPIO_PINS_PER_BANK - 1;
> -	struct reg_field alt_reg = REG_FIELD((data->alt + bank) * 4, 0, 31);
> -	struct reg_field oe_reg = REG_FIELD((data->oe + bank/4) * 4, lsb, msb);
> -	struct reg_field pu_reg = REG_FIELD((data->pu + bank/4) * 4, lsb, msb);
> -	struct reg_field od_reg = REG_FIELD((data->od + bank/4) * 4, lsb, msb);
>  	struct st_pio_control *pc = &info->banks[bank].pc;
>  	struct device *dev = info->dev;
>  	struct regmap *regmap  = info->regmap;
>  
> -	pc->alt = devm_regmap_field_alloc(dev, regmap, alt_reg);
> -	pc->oe = devm_regmap_field_alloc(dev, regmap, oe_reg);
> -	pc->pu = devm_regmap_field_alloc(dev, regmap, pu_reg);
> -	pc->od = devm_regmap_field_alloc(dev, regmap, od_reg);
> -
> -	if (IS_ERR(pc->alt) || IS_ERR(pc->oe) ||
> -			IS_ERR(pc->pu) || IS_ERR(pc->od))
> -		return -EINVAL;
> +	pc->alt = st_pc_get_value(dev, regmap, bank, data->alt, 0, 31);
> +	pc->oe = st_pc_get_value(dev, regmap, bank/4, data->oe, lsb, msb);
> +	pc->pu = st_pc_get_value(dev, regmap, bank/4, data->pu, lsb, msb);
> +	pc->od = st_pc_get_value(dev, regmap, bank/4, data->od, lsb, msb);
>  
>  	/* retime avaiable for all pins by default */
>  	pc->rt_pin_mask = 0xff;
>  	of_property_read_u32(np, "st,retime-pin-mask", &pc->rt_pin_mask);
>  	st_pctl_dt_setup_retime(info, bank, pc);
>  
> -	return 0;
> +	return;
>  }
>  
>  /*

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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