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>
---
drivers/pinctrl/mediatek/pinctrl-paris.c | 99 ++++++++++++++++++++++++
1 file changed, 99 insertions(+)
diff --git a/drivers/pinctrl/mediatek/pinctrl-paris.c b/drivers/pinctrl/mediatek/pinctrl-paris.c
index 1ea3f3c54ef3..25d999848c2a 100644
--- a/drivers/pinctrl/mediatek/pinctrl-paris.c
+++ b/drivers/pinctrl/mediatek/pinctrl-paris.c
@@ -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;
}
--
2.35.1.616.g0bdcbb4464-goog