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pinctrl: mediatek: paris: Support generic PIN_CONFIG_DRIVE_STRENGTH_UA

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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: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220308100956.2750295-9-wenst@chromium.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Chen-Yu Tsai 2022-03-08 18:09:53 +08:00 committed by Linus Walleij
parent 9b780fa1ff
commit e5fabbe43f
1 changed files with 99 additions and 0 deletions
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99
drivers/pinctrl/mediatek/pinctrl-paris.c
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@ -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;
}