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Date: Mon, 14 Feb 2011 18:08:51 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
cc: Andrew Morton <akpm@...ux-foundation.org>,
Gregory Bean <gbean@...eaurora.org>,
Jean Delvare <khali@...ux-fr.org>,
Lennert Buytenhek <buytenh@...retlab.ca>
Subject: Re: [patch] drivers: gpio: sx150x: Do not access I2C from mask/unmask
functions
On Mon, 14 Feb 2011, Thomas Gleixner wrote:
Ooops. quilt refresh should be mandatory for quilt mail. One day I'll fix that.
------->
Subject: drivers: gpio: sx150x: Do not access I2C from mask/unmask functions
From: Thomas Gleixner <tglx@...utronix.de>
Date: Mon, 14 Feb 2011 16:58:11 +0100
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@...utronix.de>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Gregory Bean <gbean@...eaurora.org>
Cc: Jean Delvare <khali@...ux-fr.org>
Cc: Lennert Buytenhek <buytenh@...retlab.ca>
---
drivers/gpio/sx150x.c | 54 ++++++++++++++++++++++++++++++++++----------------
1 file changed, 37 insertions(+), 17 deletions(-)
Index: linux-2.6-tip/drivers/gpio/sx150x.c
===================================================================
--- linux-2.6-tip.orig/drivers/gpio/sx150x.c
+++ linux-2.6-tip/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_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
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 ir
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(s
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 sx15
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)
--
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