gpio/sx150x: Do not access I2C from mask/unmask functions

irq_chip->irq_mask/unmask are called with interrupts disabled and
irq_desc->lock held. So we cannot access i2c from this context. That's
what irq_bus_sync_unlock() is for.

Store the masked information in the chip data structure and update the
i2c bus from the irq_bus_sync_unlock() callback.

This does not need a while(pending) loop because the update to this is
always serialized via the bus lock, so we never have more than one pin
update pending.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Gregory Bean <gbean@codeaurora.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Lennert Buytenhek <buytenh@secretlab.ca>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 37 insertions, 17 deletions

diff --git a/drivers/gpio/sx150x.c b/drivers/gpio/sx150x.c
index e60be0015c9b..d2f874c3d3d5 100644
--- a/drivers/gpio/sx150x.c
+++ b/drivers/gpio/sx150x.c
@@ -25,6 +25,8 @@
 #include <linux/workqueue.h>
 #include <linux/i2c/sx150x.h>
 
+#define NO_UPDATE_PENDING       -1
+
 struct sx150x_device_data {
         u8 reg_pullup;
         u8 reg_pulldn;
@@ -47,8 +49,11 @@ struct sx150x_chip {
         const struct sx150x_device_data *dev_cfg;
         int                              irq_summary;
         int                              irq_base;
+        int                              irq_update;
         u32                              irq_sense;
-        unsigned long                    irq_set_type_pending;
+        u32                              irq_masked;
+        u32                              dev_sense;
+        u32                              dev_masked;
         struct irq_chip                  irq_chip;
         struct mutex                     lock;
 };
@@ -312,9 +317,8 @@ static void sx150x_irq_mask(struct irq_data *d)
 
         chip = container_of(ic, struct sx150x_chip, irq_chip);
         n = d->irq - chip->irq_base;
-
-        sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 1);
-        sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense, 0);
+        chip->irq_masked |= (1 << n);
+        chip->irq_update = n;
 }
 
 static void sx150x_irq_unmask(struct irq_data *d)
@@ -326,9 +330,8 @@ static void sx150x_irq_unmask(struct irq_data *d)
         chip = container_of(ic, struct sx150x_chip, irq_chip);
         n = d->irq - chip->irq_base;
 
-        sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 0);
-        sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense,
-                         chip->irq_sense >> (n * 2));
+        chip->irq_masked &= ~(1 << n);
+        chip->irq_update = n;
 }
 
 static int sx150x_irq_set_type(struct irq_data *d, unsigned int flow_type)
@@ -350,7 +353,7 @@ static int sx150x_irq_set_type(struct irq_data *d, unsigned int flow_type)
 
         chip->irq_sense &= ~(3UL << (n * 2));
         chip->irq_sense |= val << (n * 2);
-        chip->irq_set_type_pending |= BIT(n);
+        chip->irq_update = n;
         return 0;
 }
 
@@ -404,15 +407,29 @@ static void sx150x_irq_bus_sync_unlock(struct irq_data *d)
 
         chip = container_of(ic, struct sx150x_chip, irq_chip);
 
-        while (chip->irq_set_type_pending) {
-                n = __ffs(chip->irq_set_type_pending);
-                chip->irq_set_type_pending &= ~BIT(n);
-                if (!(irq_to_desc(n + chip->irq_base)->status & IRQ_MASKED))
-                        sx150x_write_cfg(chip, n, 2,
-                                        chip->dev_cfg->reg_sense,
-                                        chip->irq_sense >> (n * 2));
-        }
+        if (chip->irq_update == NO_UPDATE_PENDING)
+                goto out;
+
+        n = chip->irq_update;
+        chip->irq_update = NO_UPDATE_PENDING;
 
+        /* Avoid updates if nothing changed */
+        if (chip->dev_sense == chip->irq_sense &&
+            chip->dev_sense == chip->irq_masked)
+                goto out;
+
+        chip->dev_sense = chip->irq_sense;
+        chip->dev_masked = chip->irq_masked;
+
+        if (chip->irq_masked & (1 << n)) {
+                sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 1);
+                sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense, 0);
+        } else {
+                sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 0);
+                sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense,
+                                 chip->irq_sense >> (n * 2));
+        }
+out:
         mutex_unlock(&chip->lock);
 }
 
@@ -445,8 +462,11 @@ static void sx150x_init_chip(struct sx150x_chip *chip,
         chip->irq_chip.irq_bus_sync_unlock = sx150x_irq_bus_sync_unlock;
         chip->irq_summary                  = -1;
         chip->irq_base                     = -1;
+        chip->irq_masked                   = ~0;
         chip->irq_sense                    = 0;
-        chip->irq_set_type_pending         = 0;
+        chip->dev_masked                   = ~0;
+        chip->dev_sense                    = 0;
+        chip->irq_update                   = NO_UPDATE_PENDING;
 }
 
 static int sx150x_init_io(struct sx150x_chip *chip, u8 base, u16 cfg)