Prev: mmotm 2010-06-11-16-40 uploaded
Next: [PATCH 0/2 v2] gpio: msm7200a: Add gpiolib support for MSM chips.
From: Gregory Bean on 11 Jun 2010 20:20
Signed-off-by: Gregory Bean <gbean(a)codeaurora.org>
---
drivers/gpio/msm7200a-gpio.c | 203 ++++++++++++++++++++++++++++++++++++++++-
include/linux/msm7200a-gpio.h | 7 ++
2 files changed, 209 insertions(+), 1 deletions(-)

diff --git a/drivers/gpio/msm7200a-gpio.c b/drivers/gpio/msm7200a-gpio.c
index 62db753..05c367d 100644
--- a/drivers/gpio/msm7200a-gpio.c
+++ b/drivers/gpio/msm7200a-gpio.c
@@ -23,13 +23,25 @@
#include <linux/kernel.h>
#include <linux/gpio.h>
#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/msm7200a-gpio.h>

+/*
+ * The INT_STATUS register latches both edge- and level-detection events,
+ * which is atypical. Turning on DONT_LATCH_LEVEL_IRQS causes level irq
+ * triggers to be forgotten across mask/unmask calls, emulating a more
+ * traditional setup.
+ */
+#define MSM_GPIO_DONT_LATCH_LEVEL_IRQS 1
+
struct msm_gpio_dev {
struct gpio_chip gpio_chip;
spinlock_t lock;
+ unsigned irq_base;
+ unsigned irq_summary;
struct msm7200a_gpio_regs regs;
};

@@ -119,12 +131,160 @@ static void gpio_chip_set(struct gpio_chip *chip, unsigned offset, int value)
spin_unlock_irqrestore(&msm_gpio->lock, irq_flags);
}

+static int gpio_chip_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+ struct msm_gpio_dev *msm_gpio = TO_MSM_GPIO_DEV(chip);
+ return msm_gpio->irq_base + offset;
+}
+
+#if MSM_GPIO_DONT_LATCH_LEVEL_IRQS
+static inline void forget_level_irq(struct msm_gpio_dev *msm_gpio,
+ unsigned offset)
+{
+ unsigned v = readl(msm_gpio->regs.int_edge);
+ unsigned b = bit(offset);
+
+ if (!(v & b))
+ writel(b, msm_gpio->regs.int_clear);
+
+}
+#else
+static inline void forget_level_irq(struct msm_gpio_dev *msm, unsigned off)
+{
+}
+#endif
+
+static void msm_gpio_irq_mask(unsigned int irq)
+{
+ unsigned long irq_flags;
+ struct msm_gpio_dev *msm_gpio = get_irq_chip_data(irq);
+ unsigned offset = irq - msm_gpio->irq_base;
+
+ spin_lock_irqsave(&msm_gpio->lock, irq_flags);
+ forget_level_irq(msm_gpio, offset);
+ clr_gpio_bit(offset, msm_gpio->regs.int_en);
+ spin_unlock_irqrestore(&msm_gpio->lock, irq_flags);
+}
+
+static void msm_gpio_irq_unmask(unsigned int irq)
+{
+ unsigned long irq_flags;
+ struct msm_gpio_dev *msm_gpio = get_irq_chip_data(irq);
+ unsigned offset = irq - msm_gpio->irq_base;
+
+ spin_lock_irqsave(&msm_gpio->lock, irq_flags);
+ forget_level_irq(msm_gpio, offset);
+ set_gpio_bit(offset, msm_gpio->regs.int_en);
+ spin_unlock_irqrestore(&msm_gpio->lock, irq_flags);
+}
+
+static int msm_gpio_irq_set_type(unsigned int irq, unsigned int flow_type)
+{
+ unsigned long irq_flags;
+ struct msm_gpio_dev *msm_gpio = get_irq_chip_data(irq);
+ unsigned offset = irq - msm_gpio->irq_base;
+
+ if ((flow_type & (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING)) ==
+ (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING))
+ return -ENOTSUPP;
+
+ if ((flow_type & (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW)) ==
+ (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW))
+ return -ENOTSUPP;
+
+ spin_lock_irqsave(&msm_gpio->lock, irq_flags);
+
+ if (flow_type & (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING)) {
+ set_gpio_bit(offset, msm_gpio->regs.int_edge);
+ irq_desc[irq].handle_irq = handle_edge_irq;
+ } else {
+ clr_gpio_bit(offset, msm_gpio->regs.int_edge);
+ irq_desc[irq].handle_irq = handle_level_irq;
+ }
+
+ if (flow_type & (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_RISING))
+ set_gpio_bit(offset, msm_gpio->regs.int_pos);
+ else
+ clr_gpio_bit(offset, msm_gpio->regs.int_pos);
+
+ spin_unlock_irqrestore(&msm_gpio->lock, irq_flags);
+
+ return 0;
+}
+
+static void msm_gpio_irq_mask_ack(unsigned int irq)
+{
+ msm_gpio_irq_mask(irq);
+}
+
+static int msm_gpio_irq_set_affinity(unsigned int irq,
+ const struct cpumask *dest)
+{
+ return -ENOTSUPP;
+}
+
+static int msm_gpio_irq_retrigger(unsigned int irq)
+{
+ return -ENOTSUPP;
+}
+
+static int msm_gpio_irq_set_wake(unsigned int irq, unsigned int on)
+{
+ return -ENOTSUPP;
+}
+
+static irqreturn_t msm_gpio_irq_handler(int irq, void *dev)
+{
+ unsigned long irq_flags;
+ int b, m;
+ unsigned e, s, v;
+
+ struct msm_gpio_dev *msm_gpio = (struct msm_gpio_dev *)dev;
+
+ /*
+ * The int_status register latches trigger events whether or not
+ * the gpio line is enabled as an interrupt source. Therefore,
+ * the set of pins which defines the interrupts which need to fire
+ * is the intersection of int_status and int_en - int_status
+ * alone provides an incomplete picture.
+ */
+ spin_lock_irqsave(&msm_gpio->lock, irq_flags);
+ s = readl(msm_gpio->regs.int_status);
+ e = readl(msm_gpio->regs.int_en);
+ v = s & e;
+ if (v)
+ writel(v, msm_gpio->regs.int_clear);
+ spin_unlock_irqrestore(&msm_gpio->lock, irq_flags);
+
+ if (!v)
+ return IRQ_NONE;
+
+ while (v) {
+ m = v & -v;
+ b = fls(m) - 1;
+ v &= ~m;
+ generic_handle_irq(msm_gpio->irq_base + b);
+ }
+ return IRQ_HANDLED;
+}
+
+static struct irq_chip msm_gpio_irq_chip = {
+ .name = "msm_gpio",
+ .mask = msm_gpio_irq_mask,
+ .mask_ack = msm_gpio_irq_mask_ack,
+ .unmask = msm_gpio_irq_unmask,
+ .set_affinity = msm_gpio_irq_set_affinity,
+ .retrigger = msm_gpio_irq_retrigger,
+ .set_type = msm_gpio_irq_set_type,
+ .set_wake = msm_gpio_irq_set_wake,
+};
+
static int msm_gpio_probe(struct platform_device *dev)
{
struct msm_gpio_dev *msm_gpio;
struct msm7200a_gpio_platform_data *pdata =
(struct msm7200a_gpio_platform_data *)dev->dev.platform_data;
- int ret;
+ int i, irq, ret;

if (!pdata)
return -EINVAL;
@@ -146,12 +306,52 @@ static int msm_gpio_probe(struct platform_device *dev)
msm_gpio->gpio_chip.direction_output = gpio_chip_direction_output;
msm_gpio->gpio_chip.get = gpio_chip_get;
msm_gpio->gpio_chip.set = gpio_chip_set;
+ msm_gpio->gpio_chip.to_irq = gpio_chip_to_irq;
+ msm_gpio->irq_base = pdata->irq_base;
+ msm_gpio->irq_summary = pdata->irq_summary;

ret = gpiochip_add(&msm_gpio->gpio_chip);
if (ret < 0)
goto err_post_malloc;

+ for (i = 0; i < msm_gpio->gpio_chip.ngpio; ++i) {
+ irq = msm_gpio->irq_base + i;
+ set_irq_chip_data(irq, msm_gpio);
+ set_irq_chip(irq, &msm_gpio_irq_chip);
+ set_irq_handler(irq, handle_level_irq);
+ set_irq_flags(irq, IRQF_VALID);
+ }
+
+ /*
+ * We use a level-triggered interrupt because of the nature
+ * of the shared GPIO-group interrupt.
+ *
+ * Many GPIO chips may be sharing the same group IRQ line, and
+ * it is possible for GPIO interrupt to re-occur while the system
+ * is still servicing the group interrupt associated with it.
+ * The group IRQ line would not de-assert and re-assert, and
+ * we'd get no second edge to cause the group IRQ to be handled again.
+ *
+ * Using a level interrupt guarantees that the group IRQ handlers
+ * will continue to be called as long as any GPIO chip in the group
+ * is asserting, even if the condition began while the group
+ * handler was in mid-pass.
+ */
+ ret = request_irq(msm_gpio->irq_summary,
+ msm_gpio_irq_handler,
+ IRQF_SHARED | IRQF_TRIGGER_HIGH,
+ dev->name,
+ msm_gpio);
+ if (ret < 0)
+ goto err_post_gpiochip_add;
+
return ret;
+err_post_gpiochip_add:
+ /*
+ * Under no circumstances should a line be held on a gpiochip
+ * which hasn't finished probing.
+ */
+ BUG_ON(gpiochip_remove(&msm_gpio->gpio_chip) < 0);
err_post_malloc:
kfree(msm_gpio);
return ret;
@@ -165,6 +365,7 @@ static int msm_gpio_remove(struct platform_device *dev)
if (ret < 0)
return ret;

+ free_irq(msm_gpio->irq_summary, msm_gpio);
kfree(msm_gpio);

return 0;
diff --git a/include/linux/msm7200a-gpio.h b/include/linux/msm7200a-gpio.h
index 3f1ef38..7af4dd6 100644
--- a/include/linux/msm7200a-gpio.h
+++ b/include/linux/msm7200a-gpio.h
@@ -33,11 +33,18 @@ struct msm7200a_gpio_regs {
void __iomem *in;
void __iomem *out;
void __iomem *oe;
+ void __iomem *int_status;
+ void __iomem *int_clear;
+ void __iomem *int_en;
+ void __iomem *int_edge;
+ void __iomem *int_pos;
};

struct msm7200a_gpio_platform_data {
unsigned gpio_base;
unsigned ngpio;
+ unsigned irq_base;
+ unsigned irq_summary;
struct msm7200a_gpio_regs regs;
};

--
1.7.0.4

--
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Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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Prev: mmotm 2010-06-11-16-40 uploaded
Next: [PATCH 0/2 v2] gpio: msm7200a: Add gpiolib support for MSM chips.