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Subject[PATCH v1 1/5] pinctrl: microchip-sgpio: lock RMW access
Date
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>
---
drivers/pinctrl/pinctrl-microchip-sgpio.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-microchip-sgpio.c b/drivers/pinctrl/pinctrl-microchip-sgpio.c
index d371b1e66092..b43302cc188a 100644
--- a/drivers/pinctrl/pinctrl-microchip-sgpio.c
+++ b/drivers/pinctrl/pinctrl-microchip-sgpio.c
@@ -19,6 +19,7 @@
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/reset.h>
+#include <linux/spinlock.h>

#include "core.h"
#include "pinconf.h"
@@ -116,6 +117,7 @@ struct sgpio_priv {
u32 clock;
struct regmap *regs;
const struct sgpio_properties *properties;
+ spinlock_t lock;
};

struct sgpio_port_addr {
@@ -229,6 +231,7 @@ static void sgpio_output_set(struct sgpio_priv *priv,
int value)
{
unsigned int bit = SGPIO_SRC_BITS * addr->bit;
+ unsigned long flags;
u32 clr, set;

switch (priv->properties->arch) {
@@ -247,7 +250,10 @@ static void sgpio_output_set(struct sgpio_priv *priv,
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,
@@ -575,10 +581,13 @@ static void microchip_sgpio_irq_settype(struct irq_data *data,
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);
@@ -595,6 +604,8 @@ static void microchip_sgpio_irq_settype(struct irq_data *data,

/* 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,
@@ -605,13 +616,16 @@ static void microchip_sgpio_irq_setreg(struct irq_data *data,
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)
@@ -833,6 +847,7 @@ static int microchip_sgpio_probe(struct platform_device *pdev)
return -ENOMEM;

priv->dev = dev;
+ spin_lock_init(&priv->lock);

reset = devm_reset_control_get_optional_shared(&pdev->dev, "switch");
if (IS_ERR(reset))
--
2.30.2
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