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Date: Wed, 13 Jun 2012 21:58:26 -0700 (PDT)
From: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
To: Linus Walleij <linus.walleij@...ricsson.com>,
Grant Likely <grant.likely@...retlab.ca>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@...il.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH 2/2][resend] gpio: pcf857x: enable gpio_to_irq() support
pcf857x chip has some pins, but interrupt pin is only 1 pin.
And gpiolib requests 1 interrupt per 1 gpio pin.
Thus, this patch added demuxed irq to pcf857x driver,
and enabled gpio_to_irq().
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
---
drivers/gpio/gpio-pcf857x.c | 146 +++++++++++++++++++++++++++++++++++++++++++
include/linux/i2c/pcf857x.h | 3 +
2 files changed, 149 insertions(+), 0 deletions(-)
diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index 076e236..a51d4f5b 100644
--- a/drivers/gpio/gpio-pcf857x.c
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -23,7 +23,12 @@
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/i2c/pcf857x.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
static const struct i2c_device_id pcf857x_id[] = {
@@ -60,7 +65,13 @@ struct pcf857x {
struct gpio_chip chip;
struct i2c_client *client;
struct mutex lock; /* protect 'out' */
+ struct work_struct work; /* irq demux work */
+ struct irq_domain *irq_domain; /* for irq demux */
+ spinlock_t slock; /* protect irq demux */
unsigned out; /* software latch */
+ unsigned status; /* current status */
+ int irq; /* real irq number */
+ int irq_demux_base; /* irq demux base */
int (*write)(struct i2c_client *client, unsigned data);
int (*read)(struct i2c_client *client);
@@ -150,6 +161,123 @@ static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
/*-------------------------------------------------------------------------*/
+static int pcf857x_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+ struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
+
+ return irq_find_mapping(gpio->irq_domain, offset);
+}
+
+static void pcf857x_irq_demux_work(struct work_struct *work)
+{
+ struct pcf857x *gpio = container_of(work,
+ struct pcf857x,
+ work);
+ int change, i, status;
+ unsigned long flags;
+
+ status = gpio->read(gpio->client);
+
+ spin_lock_irqsave(&gpio->slock, flags);
+ change = gpio->status ^ status;
+
+ for (i = 0; i < gpio->chip.ngpio; i++)
+ if (change & BIT(i))
+ generic_handle_irq(irq_find_mapping(gpio->irq_domain, i));
+
+ gpio->status = status;
+ spin_unlock_irqrestore(&gpio->slock, flags);
+}
+
+static irqreturn_t pcf857x_irq_demux(int irq, void *data)
+{
+ struct pcf857x *gpio = data;
+
+ /*
+ * pcf857x can't read/write data here,
+ * since i2c data access might go to sleep.
+ */
+ schedule_work(&gpio->work);
+
+ return IRQ_HANDLED;
+}
+
+static void pcf857x_nothing(struct irq_data *data)
+{
+ /* do nothing */
+}
+
+static struct irq_chip pcf857x_irq_chip = {
+ .name = "pcf857x cascade",
+ .irq_mask = pcf857x_nothing,
+ .irq_unmask = pcf857x_nothing,
+};
+
+static int pcf857x_irq_domain_map(struct irq_domain *domain, unsigned int virq,
+ irq_hw_number_t hw)
+{
+ irq_set_chip_and_handler(virq,
+ &pcf857x_irq_chip,
+ handle_level_irq);
+ return 0;
+}
+
+static struct irq_domain_ops pcf857x_irq_domain_ops = {
+ .map = pcf857x_irq_domain_map,
+};
+
+static void pcf857x_irq_domain_cleanup(struct pcf857x *gpio)
+{
+ if (gpio->irq_demux_base > 0)
+ irq_free_descs(gpio->irq_demux_base, gpio->chip.ngpio);
+
+ if (gpio->irq_domain)
+ irq_domain_remove(gpio->irq_domain);
+
+ if (gpio->irq)
+ free_irq(gpio->irq, gpio);
+}
+
+static int pcf857x_irq_domain_init(struct pcf857x *gpio,
+ struct pcf857x_platform_data *pdata,
+ struct device *dev)
+{
+ int status;
+
+ /* create demuxed irq */
+ gpio->irq_demux_base = irq_alloc_descs(-1, 0, gpio->chip.ngpio, 0);
+ if (gpio->irq_demux_base < 0)
+ return -ENODEV;
+
+ gpio->irq_domain = irq_domain_add_legacy(dev->of_node,
+ gpio->chip.ngpio,
+ gpio->irq_demux_base,
+ 0,
+ &pcf857x_irq_domain_ops,
+ NULL);
+ if (!gpio->irq_domain)
+ goto fail;
+
+ /* enable real irq */
+ status = request_irq(pdata->irq, pcf857x_irq_demux, 0,
+ dev_name(dev), gpio);
+ if (status)
+ goto fail;
+
+ /* enable gpio_to_irq() */
+ INIT_WORK(&gpio->work, pcf857x_irq_demux_work);
+ gpio->chip.to_irq = pcf857x_to_irq;
+ gpio->irq = pdata->irq;
+
+ return 0;
+
+fail:
+ pcf857x_irq_domain_cleanup(gpio);
+ return -EINVAL;
+}
+
+/*-------------------------------------------------------------------------*/
+
static int pcf857x_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -168,6 +296,7 @@ static int pcf857x_probe(struct i2c_client *client,
return -ENOMEM;
mutex_init(&gpio->lock);
+ spin_lock_init(&gpio->slock);
gpio->chip.base = pdata ? pdata->gpio_base : -1;
gpio->chip.can_sleep = 1;
@@ -179,6 +308,15 @@ static int pcf857x_probe(struct i2c_client *client,
gpio->chip.direction_output = pcf857x_output;
gpio->chip.ngpio = id->driver_data;
+ /* enable gpio_to_irq() if platform has settings */
+ if (pdata->irq) {
+ status = pcf857x_irq_domain_init(gpio, pdata, &client->dev);
+ if (status < 0) {
+ dev_err(&client->dev, "irq_domain init failed\n");
+ goto fail;
+ }
+ }
+
/* NOTE: the OnSemi jlc1562b is also largely compatible with
* these parts, notably for output. It has a low-resolution
* DAC instead of pin change IRQs; and its inputs can be the
@@ -248,6 +386,7 @@ static int pcf857x_probe(struct i2c_client *client,
* all-ones reset state. Otherwise it flags pins to be driven low.
*/
gpio->out = pdata ? ~pdata->n_latch : ~0;
+ gpio->status = gpio->out;
status = gpiochip_add(&gpio->chip);
if (status < 0)
@@ -278,6 +417,10 @@ static int pcf857x_probe(struct i2c_client *client,
fail:
dev_dbg(&client->dev, "probe error %d for '%s'\n",
status, client->name);
+
+ if (pdata->irq)
+ pcf857x_irq_domain_cleanup(gpio);
+
kfree(gpio);
return status;
}
@@ -299,6 +442,9 @@ static int pcf857x_remove(struct i2c_client *client)
}
}
+ if (pdata->irq)
+ pcf857x_irq_domain_cleanup(gpio);
+
status = gpiochip_remove(&gpio->chip);
if (status == 0)
kfree(gpio);
diff --git a/include/linux/i2c/pcf857x.h b/include/linux/i2c/pcf857x.h
index 0767a2a..781e6bd 100644
--- a/include/linux/i2c/pcf857x.h
+++ b/include/linux/i2c/pcf857x.h
@@ -10,6 +10,7 @@
* @setup: optional callback issued once the GPIOs are valid
* @teardown: optional callback issued before the GPIOs are invalidated
* @context: optional parameter passed to setup() and teardown()
+ * @irq: optional interrupt number
*
* In addition to the I2C_BOARD_INFO() state appropriate to each chip,
* the i2c_board_info used with the pcf875x driver must provide its
@@ -39,6 +40,8 @@ struct pcf857x_platform_data {
int gpio, unsigned ngpio,
void *context);
void *context;
+
+ int irq;
};
#endif /* __LINUX_PCF857X_H */
--
1.7.5.4
--
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