Merge tag 'pinctrl-v6.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl

Pull pin control fixes from Linus Walleij:

 - Concurrent register updates in the Qualcomm LPASS pin controller gets
   a proper lock.

 - revert a mutex fix that was causing problems: contention on the mutex
   or something of the sort lead to probe reordering and MMC block
   devices start to register in a different order, which unsuspecting
   userspace is not ready to handle

* tag 'pinctrl-v6.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  Revert "pinctrl: avoid unsafe code pattern in find_pinctrl()"
  pinctrl: qcom: lpass-lpi: fix concurrent register updates

Author: torvalds

drivers/pinctrl/core.c

@@ -1022,20 +1022,17 @@ static int add_setting(struct pinctrl *p, struct pinctrl_dev *pctldev,
 
 static struct pinctrl *find_pinctrl(struct device *dev)
 {
-	struct pinctrl *entry, *p = NULL;
+	struct pinctrl *p;
 
 	mutex_lock(&pinctrl_list_mutex);
-
-	list_for_each_entry(entry, &pinctrl_list, node) {
-		if (entry->dev == dev) {
-			p = entry;
-			kref_get(&p->users);
-			break;
+	list_for_each_entry(p, &pinctrl_list, node)
+		if (p->dev == dev) {
+			mutex_unlock(&pinctrl_list_mutex);
+			return p;
 		}
-	}
 
 	mutex_unlock(&pinctrl_list_mutex);
-	return p;
+	return NULL;
 }
 
 static void pinctrl_free(struct pinctrl *p, bool inlist);
@@ -1143,6 +1140,7 @@ struct pinctrl *pinctrl_get(struct device *dev)
 	p = find_pinctrl(dev);
 	if (p) {
 		dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n");
+		kref_get(&p->users);
 		return p;
 	}
 

drivers/pinctrl/qcom/pinctrl-lpass-lpi.c

@@ -32,7 +32,8 @@ struct lpi_pinctrl {
 	char __iomem *tlmm_base;
 	char __iomem *slew_base;
 	struct clk_bulk_data clks[MAX_LPI_NUM_CLKS];
-	struct mutex slew_access_lock;
+	/* Protects from concurrent register updates */
+	struct mutex lock;
 	DECLARE_BITMAP(ever_gpio, MAX_NR_GPIO);
 	const struct lpi_pinctrl_variant_data *data;
 };
@@ -103,6 +104,7 @@ static int lpi_gpio_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
 	if (WARN_ON(i == g->nfuncs))
 		return -EINVAL;
 
+	mutex_lock(&pctrl->lock);
 	val = lpi_gpio_read(pctrl, pin, LPI_GPIO_CFG_REG);
 
 	/*
@@ -128,6 +130,7 @@ static int lpi_gpio_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
 
 	u32p_replace_bits(&val, i, LPI_GPIO_FUNCTION_MASK);
 	lpi_gpio_write(pctrl, pin, LPI_GPIO_CFG_REG, val);
+	mutex_unlock(&pctrl->lock);
 
 	return 0;
 }
@@ -233,14 +236,14 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group,
 			if (slew_offset == LPI_NO_SLEW)
 				break;
 
-			mutex_lock(&pctrl->slew_access_lock);
+			mutex_lock(&pctrl->lock);
 
 			sval = ioread32(pctrl->slew_base + LPI_SLEW_RATE_CTL_REG);
 			sval &= ~(LPI_SLEW_RATE_MASK << slew_offset);
 			sval |= arg << slew_offset;
 			iowrite32(sval, pctrl->slew_base + LPI_SLEW_RATE_CTL_REG);
 
-			mutex_unlock(&pctrl->slew_access_lock);
+			mutex_unlock(&pctrl->lock);
 			break;
 		default:
 			return -EINVAL;
@@ -256,6 +259,7 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group,
 		lpi_gpio_write(pctrl, group, LPI_GPIO_VALUE_REG, val);
 	}
 
+	mutex_lock(&pctrl->lock);
 	val = lpi_gpio_read(pctrl, group, LPI_GPIO_CFG_REG);
 
 	u32p_replace_bits(&val, pullup, LPI_GPIO_PULL_MASK);
@@ -264,6 +268,7 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group,
 	u32p_replace_bits(&val, output_enabled, LPI_GPIO_OE_MASK);
 
 	lpi_gpio_write(pctrl, group, LPI_GPIO_CFG_REG, val);
+	mutex_unlock(&pctrl->lock);
 
 	return 0;
 }
@@ -461,7 +466,7 @@ int lpi_pinctrl_probe(struct platform_device *pdev)
 	pctrl->chip.label = dev_name(dev);
 	pctrl->chip.can_sleep = false;
 
-	mutex_init(&pctrl->slew_access_lock);
+	mutex_init(&pctrl->lock);
 
 	pctrl->ctrl = devm_pinctrl_register(dev, &pctrl->desc, pctrl);
 	if (IS_ERR(pctrl->ctrl)) {
@@ -483,7 +488,7 @@ int lpi_pinctrl_probe(struct platform_device *pdev)
 	return 0;
 
 err_pinctrl:
-	mutex_destroy(&pctrl->slew_access_lock);
+	mutex_destroy(&pctrl->lock);
 	clk_bulk_disable_unprepare(MAX_LPI_NUM_CLKS, pctrl->clks);
 
 	return ret;
@@ -495,7 +500,7 @@ int lpi_pinctrl_remove(struct platform_device *pdev)
 	struct lpi_pinctrl *pctrl = platform_get_drvdata(pdev);
 	int i;
 
-	mutex_destroy(&pctrl->slew_access_lock);
+	mutex_destroy(&pctrl->lock);
 	clk_bulk_disable_unprepare(MAX_LPI_NUM_CLKS, pctrl->clks);
 
 	for (i = 0; i < pctrl->data->npins; i++)