Commit e5fabbe4 authored by Chen-Yu Tsai's avatar Chen-Yu Tsai Committed by Linus Walleij
Browse files

pinctrl: mediatek: paris: Support generic PIN_CONFIG_DRIVE_STRENGTH_UA 



Some of the MediaTek chips that utilize the Paris pinctrl driver library
support a lower drive strength (<= 1mA) than the standard drive strength
settings (2~16 mA) on certain pins. This was previously supported by the
custom MTK_PIN_CONFIG_DRV_ADV parameter along with the
"mediatek,drive-strength-adv" device tree property.

The drive strength values for this hardware are 125, 250, 500, and 1000 mA,
and can be readily described by the existing "drive-strength-microamp"
property, which then gets parsed by the generic pinconf library into the
parameter PIN_CONFIG_DRIVE_STRENGTH_UA.

Add support for PIN_CONFIG_DRIVE_STRENGTH_UA while keeping the old
custom parameter around for backward compatibility.

Signed-off-by: default avatarChen-Yu Tsai <wenst@chromium.org>
Reviewed-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220308100956.2750295-9-wenst@chromium.org


Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 9b780fa1

drivers/pinctrl/mediatek/pinctrl-paris.c

+99 −0
Original line number Diff line number Diff line
@@ -48,6 +48,53 @@ static const char * const mtk_gpio_functions[] = { 
	"func12", "func13", "func14", "func15",

};



/*

 * This section supports converting to/from custom MTK_PIN_CONFIG_DRV_ADV

 * and standard PIN_CONFIG_DRIVE_STRENGTH_UA pin configs.

 *

 * The custom value encodes three hardware bits as follows:

 *

 *   |           Bits           |

 *   | 2 (E1) | 1 (E0) | 0 (EN) | drive strength (uA)

 *   ------------------------------------------------

 *   |    x   |    x   |    0   | disabled, use standard drive strength

 *   -------------------------------------

 *   |    0   |    0   |    1   |  125 uA

 *   |    0   |    1   |    1   |  250 uA

 *   |    1   |    0   |    1   |  500 uA

 *   |    1   |    1   |    1   | 1000 uA

 */

static const int mtk_drv_adv_uA[] = { 125, 250, 500, 1000 };



static int mtk_drv_adv_to_uA(int val)

{

	/* This should never happen. */

	if (WARN_ON_ONCE(val < 0 || val > 7))

		return -EINVAL;



	/* Bit 0 simply enables this hardware part */

	if (!(val & BIT(0)))

		return -EINVAL;



	return mtk_drv_adv_uA[(val >> 1)];

}



static int mtk_drv_uA_to_adv(int val)

{

	switch (val) {

	case 125:

		return 0x1;

	case 250:

		return 0x3;

	case 500:

		return 0x5;

	case 1000:

		return 0x7;

	}



	return -EINVAL;

}



static int mtk_pinmux_gpio_request_enable(struct pinctrl_dev *pctldev,

					  struct pinctrl_gpio_range *range,

					  unsigned int pin)
@@ -145,8 +192,35 @@ static int mtk_pinconf_get(struct pinctrl_dev *pctldev, 
	case PIN_CONFIG_DRIVE_STRENGTH:

		if (!hw->soc->drive_get)

			break;



		if (hw->soc->adv_drive_get) {

			err = hw->soc->adv_drive_get(hw, desc, &ret);

			if (!err) {

				err = mtk_drv_adv_to_uA(ret);

				if (err > 0) {

					/* PIN_CONFIG_DRIVE_STRENGTH_UA used */

					err = -EINVAL;

					break;

				}

			}

		}



		err = hw->soc->drive_get(hw, desc, &ret);

		break;

	case PIN_CONFIG_DRIVE_STRENGTH_UA:

		if (!hw->soc->adv_drive_get)

			break;



		err = hw->soc->adv_drive_get(hw, desc, &ret);

		if (err)

			break;

		err = mtk_drv_adv_to_uA(ret);

		if (err < 0)

			break;



		ret = err;

		err = 0;

		break;

	case MTK_PIN_CONFIG_TDSEL:

	case MTK_PIN_CONFIG_RDSEL:

		reg = (param == MTK_PIN_CONFIG_TDSEL) ?
@@ -252,6 +326,15 @@ static int mtk_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin, 
			break;

		err = hw->soc->drive_set(hw, desc, arg);

		break;

	case PIN_CONFIG_DRIVE_STRENGTH_UA:

		if (!hw->soc->adv_drive_set)

			break;



		err = mtk_drv_uA_to_adv(arg);

		if (err < 0)

			break;

		err = hw->soc->adv_drive_set(hw, desc, err);

		break;

	case MTK_PIN_CONFIG_TDSEL:

	case MTK_PIN_CONFIG_RDSEL:

		reg = (param == MTK_PIN_CONFIG_TDSEL) ?
@@ -720,6 +803,8 @@ static int mtk_pconf_group_set(struct pinctrl_dev *pctldev, unsigned group, 
{

	struct mtk_pinctrl *hw = pinctrl_dev_get_drvdata(pctldev);

	struct mtk_pinctrl_group *grp = &hw->groups[group];

	bool drive_strength_uA_found = false;

	bool adv_drve_strength_found = false;

	int i, ret;



	for (i = 0; i < num_configs; i++) {
@@ -728,8 +813,22 @@ static int mtk_pconf_group_set(struct pinctrl_dev *pctldev, unsigned group, 
				      pinconf_to_config_argument(configs[i]));

		if (ret < 0)

			return ret;



		if (pinconf_to_config_param(configs[i]) == PIN_CONFIG_DRIVE_STRENGTH_UA)

			drive_strength_uA_found = true;

		if (pinconf_to_config_param(configs[i]) == MTK_PIN_CONFIG_DRV_ADV)

			adv_drve_strength_found = true;

	}



	/*

	 * Disable advanced drive strength mode if drive-strength-microamp

	 * is not set. However, mediatek,drive-strength-adv takes precedence

	 * as its value can explicitly request the mode be enabled or not.

	 */

	if (hw->soc->adv_drive_set && !drive_strength_uA_found &&

	    !adv_drve_strength_found)

		hw->soc->adv_drive_set(hw, &hw->soc->pins[grp->pin], 0);



	return 0;

}