[PATCH 4/5] pinctrl: Rockchip: implement drive strength setting

[Ahmad Fatoum]

On 08.06.21 16:05, Sascha Hauer wrote:
> Newer SoCs support a drive strength setting per pin. This patch adds
> support for it. Currently a no-op as no currently supported SoC in the
> driver has support for this.

Thanks. I've a rk3399 that should make use of this soon. :)

> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  drivers/pinctrl/pinctrl-rockchip.c | 126 ++++++++++++++++++++++++++++-
>  1 file changed, 125 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c
> index 4b69d0d069..3bdae5c229 100644
> --- a/drivers/pinctrl/pinctrl-rockchip.c
> +++ b/drivers/pinctrl/pinctrl-rockchip.c
> @@ -186,6 +186,8 @@ struct rockchip_pin_ctrl {
>  	u32				niomux_routes;
>  	void	(*pull_calc_reg)(struct rockchip_pin_bank *bank, int pin_num,
>  				 void __iomem **reg, u8 *bit);
> +	void	(*drv_calc_reg)(struct rockchip_pin_bank *bank,
> +				    int pin_num, void __iomem **reg, u8 *bit);
>  };
>  
>  struct rockchip_pinctrl {
> @@ -468,12 +470,129 @@ static int rockchip_pinctrl_set_pull(struct rockchip_pin_bank *bank,
>  	return 0;
>  }
>  
> +static int rockchip_perpin_drv_list[DRV_TYPE_MAX][8] = {
> +	{ 2, 4, 8, 12, -1, -1, -1, -1 },
> +	{ 3, 6, 9, 12, -1, -1, -1, -1 },
> +	{ 5, 10, 15, 20, -1, -1, -1, -1 },
> +	{ 4, 6, 8, 10, 12, 14, 16, 18 },
> +	{ 4, 7, 10, 13, 16, 19, 22, 26 }
> +};
> +
> +#define RK3288_DRV_BITS_PER_PIN		2
> +#define RK3399_DRV_3BITS_PER_PIN	3
> +
> +static int rockchip_set_drive_perpin(struct rockchip_pin_bank *bank,
> +				     int pin_num, int strength)
> +{
> +	struct rockchip_pinctrl *info = bank->drvdata;
> +	struct rockchip_pin_ctrl *ctrl = info->ctrl;
> +	int ret, i;
> +	void __iomem *reg;
> +	u32 data, rmask, rmask_bits, temp, val;
> +	u8 bit;
> +	int drv_type = bank->drv[pin_num / 8].drv_type;
> +
> +	if (!ctrl->drv_calc_reg)
> +		return -ENOTSUPP;
> +
> +	dev_dbg(info->pctl_dev.dev, "setting drive of GPIO%d-%d to %d\n",
> +		bank->bank_num, pin_num, strength);
> +
> +	ctrl->drv_calc_reg(bank, pin_num, &reg, &bit);
> +
> +	ret = -EINVAL;
> +	for (i = 0; i < ARRAY_SIZE(rockchip_perpin_drv_list[drv_type]); i++) {
> +		if (rockchip_perpin_drv_list[drv_type][i] == strength) {
> +			ret = i;
> +			break;
> +		} else if (rockchip_perpin_drv_list[drv_type][i] < 0) {
> +			ret = rockchip_perpin_drv_list[drv_type][i];
> +			break;
> +		}
> +	}
> +
> +	if (ret < 0) {
> +		dev_err(info->pctl_dev.dev, "unsupported driver strength %d\n",
> +			strength);
> +		return ret;
> +	}
> +
> +	switch (drv_type) {
> +	case DRV_TYPE_IO_1V8_3V0_AUTO:
> +	case DRV_TYPE_IO_3V3_ONLY:
> +		rmask_bits = RK3399_DRV_3BITS_PER_PIN;
> +		switch (bit) {
> +		case 0 ... 12:
> +			/* regular case, nothing to do */
> +			break;
> +		case 15:
> +			/*
> +			 * drive-strength offset is special, as it is spread
> +			 * over 2 registers, the bit data[15] contains bit 0
> +			 * of the value while temp[1:0] contains bits 2 and 1
> +			 */
> +			data = (ret & 0x1) << 15;
> +			temp = (ret >> 0x1) & 0x3;
> +
> +			rmask = BIT(15) | BIT(31);
> +			data |= BIT(31);
> +
> +			val = readl(reg);
> +			val &= ~rmask;
> +			val |= data & rmask;
> +			writel(val, reg);
> +
> +			rmask = 0x3 | (0x3 << 16);
> +			temp |= (0x3 << 16);
> +			reg += 0x4;
> +
> +			val = readl(reg);
> +			val &= ~rmask;
> +			val |= temp & rmask;
> +			writel(val, reg);
> +
> +			return ret;
> +		case 18 ... 21:
> +			/* setting fully enclosed in the second register */
> +			reg += 4;
> +			bit -= 16;
> +			break;
> +		default:
> +			dev_err(info->pctl_dev.dev, "unsupported bit: %d for pinctrl drive type: %d\n",
> +				bit, drv_type);
> +			return -EINVAL;
> +		}
> +		break;
> +	case DRV_TYPE_IO_DEFAULT:
> +	case DRV_TYPE_IO_1V8_OR_3V0:
> +	case DRV_TYPE_IO_1V8_ONLY:
> +		rmask_bits = RK3288_DRV_BITS_PER_PIN;
> +		break;
> +	default:
> +		dev_err(info->pctl_dev.dev, "unsupported pinctrl drive type: %d\n",
> +			drv_type);
> +		return -EINVAL;
> +	}
> +
> +	/* enable the write to the equivalent lower bits */
> +	data = ((1 << rmask_bits) - 1) << (bit + 16);
> +	rmask = data | (data >> 16);
> +	data |= (ret << bit);
> +
> +	val = readl(reg);
> +	val &= ~rmask;
> +	val |= data & rmask;
> +	writel(val, reg);
> +
> +	return ret;
> +}
> +
>  static int rockchip_pinctrl_set_state(struct pinctrl_device *pdev,
>  				      struct device_node *np)
>  {
>  	struct rockchip_pinctrl *info = to_rockchip_pinctrl(pdev);
>  	const __be32 *list;
> -	int i, size;
> +	int i, size, ret;
>  	int bank_num, pin_num, func;
>  
>  	/*
> @@ -492,6 +611,7 @@ static int rockchip_pinctrl_set_state(struct pinctrl_device *pdev,
>  		const __be32 *phandle;
>  		struct device_node *np_config;
>  		struct rockchip_pin_bank *bank;
> +		u32 drive_strength;
>  
>  		bank_num = be32_to_cpu(*list++);
>  		pin_num = be32_to_cpu(*list++);
> @@ -506,6 +626,10 @@ static int rockchip_pinctrl_set_state(struct pinctrl_device *pdev,
>  		rockchip_pinctrl_set_func(bank, pin_num, func);
>  		rockchip_pinctrl_set_pull(bank, pin_num,
>  					  parse_bias_config(np_config));
> +
> +		ret = of_property_read_u32(np_config, "drive-strength", &drive_strength);
> +		if (!ret)
> +			rockchip_set_drive_perpin(bank, pin_num, drive_strength);
>  	}
>  
>  	return 0;
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |