Re: [PATCH 0/2][resend] gpio: pcf857x: enable gpio_to_irq()

Re: [PATCH 0/2][resend] gpio: pcf857x: enable gpio_to_irq()

[Kuninori Morimoto]

These patches add gpio_to_irq() support for gpio-pcf857x.

Kuninori Morimoto (2):
       gpio: pcf857x: share 8/16 bit access functions
       gpio: pcf857x: enable gpio_to_irq() support
 
I'm using pcf857x, and gpio_keys_polled driver, since pcf857x didn't support irq.
pcf857x has some pins, but interrupt is only 1 pin.
So, these patches add irq demux support on pcf857x driver,
and enabled gpio_to_irq().
Now, I can use both gpio_keys / gpio_keys_polled

These patches are based on latest linus/master branch

[PATCH 1/2][resend] gpio: pcf857x: share 8/16 bit access functions

[Kuninori Morimoto]

This patch adds 8/16 bit write/read functions,
and shared gpio input/output/set/get functions.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 drivers/gpio/gpio-pcf857x.c |   93 ++++++++++++++----------------------------
 1 files changed, 31 insertions(+), 62 deletions(-)

diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index 2d1de9e..076e236 100644
--- a/drivers/gpio/gpio-pcf857x.c
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -61,61 +61,28 @@ struct pcf857x {
 	struct i2c_client	*client;
 	struct mutex		lock;		/* protect 'out' */
 	unsigned		out;		/* software latch */
+
+	int (*write)(struct i2c_client *client, unsigned data);
+	int (*read)(struct i2c_client *client);
 };
 
 /*-------------------------------------------------------------------------*/
 
 /* Talk to 8-bit I/O expander */
 
-static int pcf857x_input8(struct gpio_chip *chip, unsigned offset)
-{
-	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
-	int		status;
-
-	mutex_lock(&gpio->lock);
-	gpio->out |= (1 << offset);
-	status = i2c_smbus_write_byte(gpio->client, gpio->out);
-	mutex_unlock(&gpio->lock);
-
-	return status;
-}
-
-static int pcf857x_get8(struct gpio_chip *chip, unsigned offset)
-{
-	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
-	s32		value;
-
-	value = i2c_smbus_read_byte(gpio->client);
-	return (value < 0) ? 0 : (value & (1 << offset));
-}
-
-static int pcf857x_output8(struct gpio_chip *chip, unsigned offset, int value)
+static int i2c_write_le8(struct i2c_client *client, unsigned data)
 {
-	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
-	unsigned	bit = 1 << offset;
-	int		status;
-
-	mutex_lock(&gpio->lock);
-	if (value)
-		gpio->out |= bit;
-	else
-		gpio->out &= ~bit;
-	status = i2c_smbus_write_byte(gpio->client, gpio->out);
-	mutex_unlock(&gpio->lock);
-
-	return status;
+	return i2c_smbus_write_byte(client, data);
 }
 
-static void pcf857x_set8(struct gpio_chip *chip, unsigned offset, int value)
+static int i2c_read_le8(struct i2c_client *client)
 {
-	pcf857x_output8(chip, offset, value);
+	return (int)i2c_smbus_read_byte(client);
 }
 
-/*-------------------------------------------------------------------------*/
-
 /* Talk to 16-bit I/O expander */
 
-static int i2c_write_le16(struct i2c_client *client, u16 word)
+static int i2c_write_le16(struct i2c_client *client, unsigned word)
 {
 	u8 buf[2] = { word & 0xff, word >> 8, };
 	int status;
@@ -135,29 +102,31 @@ static int i2c_read_le16(struct i2c_client *client)
 	return (buf[1] << 8) | buf[0];
 }
 
-static int pcf857x_input16(struct gpio_chip *chip, unsigned offset)
+/*-------------------------------------------------------------------------*/
+
+static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
 {
 	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
 	int		status;
 
 	mutex_lock(&gpio->lock);
 	gpio->out |= (1 << offset);
-	status = i2c_write_le16(gpio->client, gpio->out);
+	status = gpio->write(gpio->client, gpio->out);
 	mutex_unlock(&gpio->lock);
 
 	return status;
 }
 
-static int pcf857x_get16(struct gpio_chip *chip, unsigned offset)
+static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
 {
 	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
 	int		value;
 
-	value = i2c_read_le16(gpio->client);
+	value = gpio->read(gpio->client);
 	return (value < 0) ? 0 : (value & (1 << offset));
 }
 
-static int pcf857x_output16(struct gpio_chip *chip, unsigned offset, int value)
+static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
 	unsigned	bit = 1 << offset;
@@ -168,15 +137,15 @@ static int pcf857x_output16(struct gpio_chip *chip, unsigned offset, int value)
 		gpio->out |= bit;
 	else
 		gpio->out &= ~bit;
-	status = i2c_write_le16(gpio->client, gpio->out);
+	status = gpio->write(gpio->client, gpio->out);
 	mutex_unlock(&gpio->lock);
 
 	return status;
 }
 
-static void pcf857x_set16(struct gpio_chip *chip, unsigned offset, int value)
+static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
 {
-	pcf857x_output16(chip, offset, value);
+	pcf857x_output(chip, offset, value);
 }
 
 /*-------------------------------------------------------------------------*/
@@ -200,10 +169,15 @@ static int pcf857x_probe(struct i2c_client *client,
 
 	mutex_init(&gpio->lock);
 
-	gpio->chip.base = pdata ? pdata->gpio_base : -1;
-	gpio->chip.can_sleep = 1;
-	gpio->chip.dev = &client->dev;
-	gpio->chip.owner = THIS_MODULE;
+	gpio->chip.base			= pdata ? pdata->gpio_base : -1;
+	gpio->chip.can_sleep		= 1;
+	gpio->chip.dev			= &client->dev;
+	gpio->chip.owner		= THIS_MODULE;
+	gpio->chip.get			= pcf857x_get;
+	gpio->chip.set			= pcf857x_set;
+	gpio->chip.direction_input	= pcf857x_input;
+	gpio->chip.direction_output	= pcf857x_output;
+	gpio->chip.ngpio		= id->driver_data;
 
 	/* NOTE:  the OnSemi jlc1562b is also largely compatible with
 	 * these parts, notably for output.  It has a low-resolution
@@ -216,12 +190,9 @@ static int pcf857x_probe(struct i2c_client *client,
 	 *
 	 * NOTE: we don't distinguish here between *4 and *4a parts.
 	 */
-	gpio->chip.ngpio = id->driver_data;
 	if (gpio->chip.ngpio == 8) {
-		gpio->chip.direction_input = pcf857x_input8;
-		gpio->chip.get = pcf857x_get8;
-		gpio->chip.direction_output = pcf857x_output8;
-		gpio->chip.set = pcf857x_set8;
+		gpio->write	= i2c_write_le8;
+		gpio->read	= i2c_read_le8;
 
 		if (!i2c_check_functionality(client->adapter,
 				I2C_FUNC_SMBUS_BYTE))
@@ -238,10 +209,8 @@ static int pcf857x_probe(struct i2c_client *client,
 	 * NOTE: we don't distinguish here between '75 and '75c parts.
 	 */
 	} else if (gpio->chip.ngpio == 16) {
-		gpio->chip.direction_input = pcf857x_input16;
-		gpio->chip.get = pcf857x_get16;
-		gpio->chip.direction_output = pcf857x_output16;
-		gpio->chip.set = pcf857x_set16;
+		gpio->write	= i2c_write_le16;
+		gpio->read	= i2c_read_le16;
 
 		if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 			status = -EIO;
-- 
1.7.5.4

Re: [PATCH 1/2][resend] gpio: pcf857x: share 8/16 bit access functions

[Linus Walleij]

On Thu, Jun 14, 2012 at 6:58 AM, Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:

> This patch adds 8/16 bit write/read functions,
> and shared gpio input/output/set/get functions.
>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

Applied.

Thanks,
Linus Walleij

[PATCH 2/2][resend] gpio: pcf857x: enable gpio_to_irq() support

[Kuninori Morimoto]

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@renesas.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

Re: [PATCH 2/2][resend] gpio: pcf857x: enable gpio_to_irq() support

[Paul Mundt]

On Wed, Jun 13, 2012 at 09:58:26PM -0700, Kuninori Morimoto wrote:
> +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,
> +};
> +
Just use dummy_irq_chip.

> +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);

Given that you don't actually care where the IRQs are mapped there's no
need to bother with a legacy domain here, you can just use a linear one
outright. At which point you can drop your separate irq_desc
allocation/management.

Re: [PATCH 2/2][resend] gpio: pcf857x: enable gpio_to_irq() support

[Kuninori Morimoto]

Hi Paul

Thank you for checking patch

> > +static struct irq_chip pcf857x_irq_chip = {
> > +	.name		= "pcf857x cascade",
> > +	.irq_mask	= pcf857x_nothing,
> > +	.irq_unmask	= pcf857x_nothing,
> > +};
> > +
> Just use dummy_irq_chip.

Thanks. I didn't know that.
OK. I fix it in v2

> > +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);
> 
> Given that you don't actually care where the IRQs are mapped there's no
> need to bother with a legacy domain here, you can just use a linear one
> outright. At which point you can drop your separate irq_desc
> allocation/management.

OK. I use linear in v2

Best regards
---
Kuninori Morimoto

[PATCH 2/2 v2][resend] gpio: pcf857x: enable gpio_to_irq() support

[Kuninori Morimoto]

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@renesas.com>
---
v1 -> v2

 - used dummy_irq_chip on irq_set_chip_and_handler()
 - used irq_domain_add_linear() instead of irq_domain_add_legacy()

 drivers/gpio/gpio-pcf857x.c |  124 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/i2c/pcf857x.h |    3 +
 2 files changed, 127 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index 076e236..7f3a25c 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 +65,12 @@ 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 (*write)(struct i2c_client *client, unsigned data);
 	int (*read)(struct i2c_client *client);
@@ -150,6 +160,102 @@ 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_create_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 int pcf857x_irq_domain_map(struct irq_domain *domain, unsigned int virq,
+				 irq_hw_number_t hw)
+{
+	irq_set_chip_and_handler(virq,
+				 &dummy_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_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;
+
+	gpio->irq_domain = irq_domain_add_linear(dev->of_node,
+						 gpio->chip.ngpio,
+						 &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 +274,7 @@ 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 +286,15 @@ 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 +364,7 @@ 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 +395,10 @@ 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 +420,9 @@ 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

Re: [PATCH 2/2 v2][resend] gpio: pcf857x: enable gpio_to_irq() support

[Paul Mundt]

On Thu, Jun 14, 2012 at 12:10:59AM -0700, Kuninori Morimoto wrote:
> +	for (i = 0; i < gpio->chip.ngpio; i++)
> +		if (change & BIT(i))
> +			generic_handle_irq(irq_find_mapping(gpio->irq_domain, i));
> +
You can probably get away with using for_each_set_bit() as well, which
would simplify this a bit.

Also, do you not have to worry about masking the parent IRQ while
iterating through the dispatch loop?

Re: [PATCH 2/2 v2][resend] gpio: pcf857x: enable gpio_to_irq() support

[Kuninori Morimoto]

Hi Paul

> On Thu, Jun 14, 2012 at 12:10:59AM -0700, Kuninori Morimoto wrote:
> > +	for (i = 0; i < gpio->chip.ngpio; i++)
> > +		if (change & BIT(i))
> > +			generic_handle_irq(irq_find_mapping(gpio->irq_domain, i));
> > +
> You can probably get away with using for_each_set_bit() as well, which
> would simplify this a bit.
> 
> Also, do you not have to worry about masking the parent IRQ while
> iterating through the dispatch loop?

This device automatically stops its IRQ until data was read.
And it is using spin_lock_irqsave(), and it needs to save prev status.
So, I guess masking parent IRQ is not needed.
But not enough/good ?

Best regards
---
Kuninori Morimoto

Re: [PATCH 2/2 v3][resend] gpio: pcf857x: enable gpio_to_irq() support

[Kuninori Morimoto]

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@renesas.com>
---
v2 -> v3

 - used for_each_set_bit()

 drivers/gpio/gpio-pcf857x.c |  122 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/i2c/pcf857x.h |    3 +
 2 files changed, 125 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index 076e236..12e3e48 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 +65,12 @@ 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 (*write)(struct i2c_client *client, unsigned data);
 	int (*read)(struct i2c_client *client);
@@ -150,6 +160,100 @@ 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_create_mapping(gpio->irq_domain, offset);
+}
+
+static void pcf857x_irq_demux_work(struct work_struct *work)
+{
+	struct pcf857x *gpio = container_of(work,
+					       struct pcf857x,
+					       work);
+	unsigned long change, i, status, flags;
+
+	status = gpio->read(gpio->client);
+
+	spin_lock_irqsave(&gpio->slock, flags);
+
+	change = gpio->status ^ status;
+	for_each_set_bit(i, &change, gpio->chip.ngpio)
+		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 int pcf857x_irq_domain_map(struct irq_domain *domain, unsigned int virq,
+				 irq_hw_number_t hw)
+{
+	irq_set_chip_and_handler(virq,
+				 &dummy_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_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;
+
+	gpio->irq_domain = irq_domain_add_linear(dev->of_node,
+						 gpio->chip.ngpio,
+						 &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 +272,7 @@ 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 +284,15 @@ 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 +362,7 @@ 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 +393,10 @@ 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 +418,9 @@ 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

Re: [PATCH 2/2 v3][resend] gpio: pcf857x: enable gpio_to_irq() support

[Linus Walleij]

On Fri, Jun 15, 2012 at 4:40 AM, Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:

> 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@renesas.com>
> ---
> v2 -> v3
>
>  - used for_each_set_bit()

Applied this v3 version as nothing has been said since.
Paul, scream if you don't like it.

Yours,
Linus Walleij