From 7996c5f5ec7a20b3f6b8fae93fcf3cb8f1c01743 Mon Sep 17 00:00:00 2001
From: Michael Walle <michael@walle.cc>
Date: Sat, 26 Feb 2022 21:45:03 +0100
Subject: [PATCH] pinctrl: microchip-sgpio: lock RMW access
Git-commit: 7996c5f5ec7a20b3f6b8fae93fcf3cb8f1c01743
Patch-mainline: v5.18-rc1
References: git-fixes

Protect any RMW access to the registers by a spinlock.

Fixes: 7e5ea974e61c ("pinctrl: pinctrl-microchip-sgpio: Add pinctrl driver for Microsemi Serial GPIO")
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220226204507.2511633-2-michael@walle.cc
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/pinctrl/pinctrl-microchip-sgpio.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/drivers/pinctrl/pinctrl-microchip-sgpio.c
+++ b/drivers/pinctrl/pinctrl-microchip-sgpio.c
@@ -18,6 +18,7 @@
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/reset.h>
+#include <linux/spinlock.h>
 
 #include "core.h"
 #include "pinconf.h"
@@ -115,6 +116,7 @@ struct sgpio_priv {
 	u32 clock;
 	u32 __iomem *regs;
 	const struct sgpio_properties *properties;
+	spinlock_t lock;
 };
 
 struct sgpio_port_addr {
@@ -216,6 +218,7 @@ static void sgpio_output_set(struct sgpi
 			     int value)
 {
 	unsigned int bit = SGPIO_SRC_BITS * addr->bit;
+	unsigned long flags;
 	u32 clr, set;
 
 	switch (priv->properties->arch) {
@@ -234,7 +237,10 @@ static void sgpio_output_set(struct sgpi
 	default:
 		return;
 	}
+
+	spin_lock_irqsave(&priv->lock, flags);
 	sgpio_clrsetbits(priv, REG_PORT_CONFIG, addr->port, clr, set);
+	spin_unlock_irqrestore(&priv->lock, flags);
 }
 
 static int sgpio_output_get(struct sgpio_priv *priv,
@@ -562,10 +568,13 @@ static void microchip_sgpio_irq_settype(
 	struct sgpio_bank *bank = gpiochip_get_data(chip);
 	unsigned int gpio = irqd_to_hwirq(data);
 	struct sgpio_port_addr addr;
+	unsigned long flags;
 	u32 ena;
 
 	sgpio_pin_to_addr(bank->priv, gpio, &addr);
 
+	spin_lock_irqsave(&bank->priv->lock, flags);
+
 	/* Disable interrupt while changing type */
 	ena = sgpio_readl(bank->priv, REG_INT_ENABLE, addr.bit);
 	sgpio_writel(bank->priv, ena & ~BIT(addr.port), REG_INT_ENABLE, addr.bit);
@@ -582,6 +591,8 @@ static void microchip_sgpio_irq_settype(
 
 	/* Possibly re-enable interrupts */
 	sgpio_writel(bank->priv, ena, REG_INT_ENABLE, addr.bit);
+
+	spin_unlock_irqrestore(&bank->priv->lock, flags);
 }
 
 static void microchip_sgpio_irq_setreg(struct irq_data *data,
@@ -592,13 +603,16 @@ static void microchip_sgpio_irq_setreg(s
 	struct sgpio_bank *bank = gpiochip_get_data(chip);
 	unsigned int gpio = irqd_to_hwirq(data);
 	struct sgpio_port_addr addr;
+	unsigned long flags;
 
 	sgpio_pin_to_addr(bank->priv, gpio, &addr);
 
+	spin_lock_irqsave(&bank->priv->lock, flags);
 	if (clear)
 		sgpio_clrsetbits(bank->priv, reg, addr.bit, BIT(addr.port), 0);
 	else
 		sgpio_clrsetbits(bank->priv, reg, addr.bit, 0, BIT(addr.port));
+	spin_unlock_irqrestore(&bank->priv->lock, flags);
 }
 
 static void microchip_sgpio_irq_mask(struct irq_data *data)
@@ -814,6 +828,7 @@ static int microchip_sgpio_probe(struct
 		return -ENOMEM;
 
 	priv->dev = dev;
+	spin_lock_init(&priv->lock);
 
 	reset = devm_reset_control_get_optional_shared(&pdev->dev, "switch");
 	if (IS_ERR(reset))