pinctrl: add lock in mtk_rmw function.

When multiple threads operate on the same register resource
which include multiple pin, It will make the register resource
wrong to control. So we add lock to avoid the case.

Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
Link: https://lore.kernel.org/r/20210321033150.15380-2-zhiyong.tao@mediatek.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/mediatek/pinctrl-moore.c

@@ -619,6 +619,8 @@ int mtk_moore_pinctrl_probe(struct platform_device *pdev,
 
 	hw->nbase = hw->soc->nbase_names;
 
+	mutex_init(&hw->lock);
+
 	/* Copy from internal struct mtk_pin_desc to register to the core */
 	pins = devm_kmalloc_array(&pdev->dev, hw->soc->npins, sizeof(*pins),
 				  GFP_KERNEL);

drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c

@@ -58,10 +58,14 @@ void mtk_rmw(struct mtk_pinctrl *pctl, u8 i, u32 reg, u32 mask, u32 set)
 {
 	u32 val;
 
+	mutex_lock(&pctl->lock);
+
 	val = mtk_r32(pctl, i, reg);
 	val &= ~mask;
 	val |= set;
 	mtk_w32(pctl, i, reg, val);
+
+	mutex_unlock(&pctl->lock);
 }
 
 static int mtk_hw_pin_field_lookup(struct mtk_pinctrl *hw,

drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h

@@ -251,6 +251,8 @@ struct mtk_pinctrl {
 	struct mtk_eint			*eint;
 	struct mtk_pinctrl_group	*groups;
 	const char          **grp_names;
+	/* lock pin's register resource to avoid multiple threads issue*/
+	struct mutex lock;
 };
 
 void mtk_rmw(struct mtk_pinctrl *pctl, u8 i, u32 reg, u32 mask, u32 set);

drivers/pinctrl/mediatek/pinctrl-paris.c

@@ -970,6 +970,8 @@ int mtk_paris_pinctrl_probe(struct platform_device *pdev,
 
 	hw->nbase = hw->soc->nbase_names;
 
+	mutex_init(&hw->lock);
+
 	err = mtk_pctrl_build_state(pdev);
 	if (err) {
 		dev_err(&pdev->dev, "build state failed: %d\n", err);