V4L/DVB (13176): adv7180: Support checking standard via interrupts

If the I2C device provides an interrupt it is registered and the
standard
is updated via interrupts rather than polling.

Since I2C communication is needed, the interrupt handler fires off a
work which will check the new standard, and store it in the internal
structure.

To handle mutual exclusion a mutex is introduced.
Signed-off-by: Richard Röjfors <richard.rojfors@mocean-labs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/adv7180.c

@@ -27,6 +27,7 @@
 #include <linux/videodev2.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-chip-ident.h>
+#include <linux/mutex.h>
 
 #define DRIVER_NAME "adv7180"
 
@@ -48,9 +49,14 @@
 #define ADV7180_INPUT_CONTROL_PAL_SECAM			0xe0
 #define ADV7180_INPUT_CONTROL_PAL_SECAM_PED		0xf0
 
-#define ADV7180_AUTODETECT_ENABLE_REG	0x07
-#define ADV7180_AUTODETECT_DEFAULT	0x7f
+#define ADV7180_EXTENDED_OUTPUT_CONTROL_REG		0x04
+#define ADV7180_EXTENDED_OUTPUT_CONTROL_NTSCDIS		0xC5
 
+#define ADV7180_AUTODETECT_ENABLE_REG			0x07
+#define ADV7180_AUTODETECT_DEFAULT			0x7f
+
+#define ADV7180_ADI_CTRL_REG				0x0e
+#define ADV7180_ADI_CTRL_IRQ_SPACE			0x20
 
 #define ADV7180_STATUS1_REG				0x10
 #define ADV7180_STATUS1_IN_LOCK		0x01
@@ -67,9 +73,28 @@
 #define ADV7180_IDENT_REG 0x11
 #define ADV7180_ID_7180 0x18
 
+#define ADV7180_ICONF1_ADI		0x40
+#define ADV7180_ICONF1_ACTIVE_LOW	0x01
+#define ADV7180_ICONF1_PSYNC_ONLY	0x10
+#define ADV7180_ICONF1_ACTIVE_TO_CLR	0xC0
+
+#define ADV7180_IRQ1_LOCK	0x01
+#define ADV7180_IRQ1_UNLOCK	0x02
+#define ADV7180_ISR1_ADI	0x42
+#define ADV7180_ICR1_ADI	0x43
+#define ADV7180_IMR1_ADI	0x44
+#define ADV7180_IMR2_ADI	0x48
+#define ADV7180_IRQ3_AD_CHANGE	0x08
+#define ADV7180_ISR3_ADI	0x4A
+#define ADV7180_ICR3_ADI	0x4B
+#define ADV7180_IMR3_ADI	0x4C
+#define ADV7180_IMR4_ADI	0x50
 
 struct adv7180_state {
 	struct v4l2_subdev	sd;
+	struct work_struct	work;
+	struct mutex		mutex; /* mutual excl. when accessing chip */
+	int			irq;
 	v4l2_std_id		curr_norm;
 	bool			autodetect;
 };
@@ -153,19 +178,30 @@ static inline struct adv7180_state *to_state(struct v4l2_subdev *sd)
 static int adv7180_querystd(struct v4l2_subdev *sd, v4l2_std_id *std)
 {
 	struct adv7180_state *state = to_state(sd);
-	int err = 0;
+	int err = mutex_lock_interruptible(&state->mutex);
+	if (err)
+		return err;
 
-	if (!state->autodetect)
+	/* when we are interrupt driven we know the state */
+	if (!state->autodetect || state->irq > 0)
 		*std = state->curr_norm;
 	else
 		err = __adv7180_status(v4l2_get_subdevdata(sd), NULL, std);
 
+	mutex_unlock(&state->mutex);
 	return err;
 }
 
 static int adv7180_g_input_status(struct v4l2_subdev *sd, u32 *status)
 {
-	return __adv7180_status(v4l2_get_subdevdata(sd), status, NULL);
+	struct adv7180_state *state = to_state(sd);
+	int ret = mutex_lock_interruptible(&state->mutex);
+	if (ret)
+		return ret;
+
+	ret = __adv7180_status(v4l2_get_subdevdata(sd), status, NULL);
+	mutex_unlock(&state->mutex);
+	return ret;
 }
 
 static int adv7180_g_chip_ident(struct v4l2_subdev *sd,
@@ -180,7 +216,9 @@ static int adv7180_s_std(struct v4l2_subdev *sd, v4l2_std_id std)
 {
 	struct adv7180_state *state = to_state(sd);
 	struct i2c_client *client = v4l2_get_subdevdata(sd);
-	int ret;
+	int ret = mutex_lock_interruptible(&state->mutex);
+	if (ret)
+		return ret;
 
 	/* all standards -> autodetect */
 	if (std == V4L2_STD_ALL) {
@@ -190,6 +228,7 @@ static int adv7180_s_std(struct v4l2_subdev *sd, v4l2_std_id std)
 		if (ret < 0)
 			goto out;
 
+		__adv7180_status(client, NULL, &state->curr_norm);
 		state->autodetect = true;
 	} else {
 		ret = v4l2_std_to_adv7180(std);
@@ -206,6 +245,7 @@ static int adv7180_s_std(struct v4l2_subdev *sd, v4l2_std_id std)
 	}
 	ret = 0;
 out:
+	mutex_unlock(&state->mutex);
 	return ret;
 }
 
@@ -224,6 +264,39 @@ static const struct v4l2_subdev_ops adv7180_ops = {
 	.video = &adv7180_video_ops,
 };
 
+static void adv7180_work(struct work_struct *work)
+{
+	struct adv7180_state *state = container_of(work, struct adv7180_state,
+		work);
+	struct i2c_client *client = v4l2_get_subdevdata(&state->sd);
+	u8 isr3;
+
+	mutex_lock(&state->mutex);
+	i2c_smbus_write_byte_data(client, ADV7180_ADI_CTRL_REG,
+		ADV7180_ADI_CTRL_IRQ_SPACE);
+	isr3 = i2c_smbus_read_byte_data(client, ADV7180_ISR3_ADI);
+	/* clear */
+	i2c_smbus_write_byte_data(client, ADV7180_ICR3_ADI, isr3);
+	i2c_smbus_write_byte_data(client, ADV7180_ADI_CTRL_REG, 0);
+
+	if (isr3 & ADV7180_IRQ3_AD_CHANGE && state->autodetect)
+		__adv7180_status(client, NULL, &state->curr_norm);
+	mutex_unlock(&state->mutex);
+
+	enable_irq(state->irq);
+}
+
+static irqreturn_t adv7180_irq(int irq, void *devid)
+{
+	struct adv7180_state *state = devid;
+
+	schedule_work(&state->work);
+
+	disable_irq_nosync(state->irq);
+
+	return IRQ_HANDLED;
+}
+
 /*
  * Generic i2c probe
  * concerning the addresses: i2c wants 7 bit (without the r/w bit), so '>>1'
@@ -244,33 +317,111 @@ static __devinit int adv7180_probe(struct i2c_client *client,
 			client->addr << 1, client->adapter->name);
 
 	state = kzalloc(sizeof(struct adv7180_state), GFP_KERNEL);
-	if (state == NULL)
-		return -ENOMEM;
+	if (state == NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	state->irq = client->irq;
+	INIT_WORK(&state->work, adv7180_work);
+	mutex_init(&state->mutex);
 	state->autodetect = true;
 	sd = &state->sd;
 	v4l2_i2c_subdev_init(sd, client, &adv7180_ops);
 
 	/* Initialize adv7180 */
-	/* enable autodetection */
+	/* Enable autodetection */
 	ret = i2c_smbus_write_byte_data(client, ADV7180_INPUT_CONTROL_REG,
 		ADV7180_INPUT_CONTROL_AD_PAL_BG_NTSC_J_SECAM);
-	if (ret > 0)
-		ret = i2c_smbus_write_byte_data(client,
-			ADV7180_AUTODETECT_ENABLE_REG,
-			ADV7180_AUTODETECT_DEFAULT);
-	if (ret < 0) {
-		printk(KERN_ERR DRIVER_NAME
-			": Failed to communicate to chip: %d\n", ret);
-		return ret;
+	if (ret < 0)
+		goto err_unreg_subdev;
+
+	ret = i2c_smbus_write_byte_data(client, ADV7180_AUTODETECT_ENABLE_REG,
+		ADV7180_AUTODETECT_DEFAULT);
+	if (ret < 0)
+		goto err_unreg_subdev;
+
+	/* ITU-R BT.656-4 compatible */
+	ret = i2c_smbus_write_byte_data(client,
+		ADV7180_EXTENDED_OUTPUT_CONTROL_REG,
+		ADV7180_EXTENDED_OUTPUT_CONTROL_NTSCDIS);
+	if (ret < 0)
+		goto err_unreg_subdev;
+
+	/* read current norm */
+	__adv7180_status(client, NULL, &state->curr_norm);
+
+	/* register for interrupts */
+	if (state->irq > 0) {
+		ret = request_irq(state->irq, adv7180_irq, 0, DRIVER_NAME,
+			state);
+		if (ret)
+			goto err_unreg_subdev;
+
+		ret = i2c_smbus_write_byte_data(client, ADV7180_ADI_CTRL_REG,
+			ADV7180_ADI_CTRL_IRQ_SPACE);
+		if (ret < 0)
+			goto err_unreg_subdev;
+
+		/* config the Interrupt pin to be active low */
+		ret = i2c_smbus_write_byte_data(client, ADV7180_ICONF1_ADI,
+			ADV7180_ICONF1_ACTIVE_LOW | ADV7180_ICONF1_PSYNC_ONLY);
+		if (ret < 0)
+			goto err_unreg_subdev;
+
+		ret = i2c_smbus_write_byte_data(client, ADV7180_IMR1_ADI, 0);
+		if (ret < 0)
+			goto err_unreg_subdev;
+
+		ret = i2c_smbus_write_byte_data(client, ADV7180_IMR2_ADI, 0);
+		if (ret < 0)
+			goto err_unreg_subdev;
+
+		/* enable AD change interrupts interrupts */
+		ret = i2c_smbus_write_byte_data(client, ADV7180_IMR3_ADI,
+			ADV7180_IRQ3_AD_CHANGE);
+		if (ret < 0)
+			goto err_unreg_subdev;
+
+		ret = i2c_smbus_write_byte_data(client, ADV7180_IMR4_ADI, 0);
+		if (ret < 0)
+			goto err_unreg_subdev;
+
+		ret = i2c_smbus_write_byte_data(client, ADV7180_ADI_CTRL_REG,
+			0);
+		if (ret < 0)
+			goto err_unreg_subdev;
 	}
 
 	return 0;
+
+err_unreg_subdev:
+	mutex_destroy(&state->mutex);
+	v4l2_device_unregister_subdev(sd);
+	kfree(state);
+err:
+	printk(KERN_ERR DRIVER_NAME ": Failed to probe: %d\n", ret);
+	return ret;
 }
 
 static __devexit int adv7180_remove(struct i2c_client *client)
 {
 	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct adv7180_state *state = to_state(sd);
+
+	if (state->irq > 0) {
+		free_irq(client->irq, state);
+		if (cancel_work_sync(&state->work)) {
+			/*
+			 * Work was pending, therefore we need to enable
+			 * IRQ here to balance the disable_irq() done in the
+			 * interrupt handler.
+			 */
+			enable_irq(state->irq);
+		}
+	}
 
+	mutex_destroy(&state->mutex);
 	v4l2_device_unregister_subdev(sd);
 	kfree(to_state(sd));
 	return 0;