V4L/DVB (13600): radio-si470x: support RDS on si470x i2c driver

This patch is to support RDS on si470x i2c driver. The routine of RDS
operation is almost same with thing of usb driver, but this uses RDS
interrupt.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Acked-by: Tobias Lorenz <tobias.lorenz@gmx.net>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/si470x/radio-si470x-i2c.c

@@ -22,22 +22,17 @@
  */
 
 
-/*
- * ToDo:
- * - RDS support
- */
-
-
 /* driver definitions */
 #define DRIVER_AUTHOR "Joonyoung Shim <jy0922.shim@samsung.com>";
-#define DRIVER_KERNEL_VERSION KERNEL_VERSION(1, 0, 0)
+#define DRIVER_KERNEL_VERSION KERNEL_VERSION(1, 0, 1)
 #define DRIVER_CARD "Silicon Labs Si470x FM Radio Receiver"
 #define DRIVER_DESC "I2C radio driver for Si470x FM Radio Receivers"
-#define DRIVER_VERSION "1.0.0"
+#define DRIVER_VERSION "1.0.1"
 
 /* kernel includes */
 #include <linux/i2c.h>
 #include <linux/delay.h>
+#include <linux/interrupt.h>
 
 #include "radio-si470x.h"
 
@@ -62,6 +57,20 @@ static int radio_nr = -1;
 module_param(radio_nr, int, 0444);
 MODULE_PARM_DESC(radio_nr, "Radio Nr");
 
+/* RDS buffer blocks */
+static unsigned int rds_buf = 100;
+module_param(rds_buf, uint, 0444);
+MODULE_PARM_DESC(rds_buf, "RDS buffer entries: *100*");
+
+/* RDS maximum block errors */
+static unsigned short max_rds_errors = 1;
+/* 0 means   0  errors requiring correction */
+/* 1 means 1-2  errors requiring correction (used by original USBRadio.exe) */
+/* 2 means 3-5  errors requiring correction */
+/* 3 means   6+ errors or errors in checkword, correction not possible */
+module_param(max_rds_errors, ushort, 0644);
+MODULE_PARM_DESC(max_rds_errors, "RDS maximum block errors: *1*");
+
 
 
 /**************************************************************************
@@ -181,12 +190,21 @@ int si470x_fops_open(struct file *file)
 	mutex_lock(&radio->lock);
 	radio->users++;
 
-	if (radio->users == 1)
+	if (radio->users == 1) {
 		/* start radio */
 		retval = si470x_start(radio);
+		if (retval < 0)
+			goto done;
+
+		/* enable RDS interrupt */
+		radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDSIEN;
+		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_GPIO2;
+		radio->registers[SYSCONFIG1] |= 0x1 << 2;
+		retval = si470x_set_register(radio, SYSCONFIG1);
+	}
 
+done:
 	mutex_unlock(&radio->lock);
-
 	return retval;
 }
 
@@ -241,6 +259,105 @@ int si470x_vidioc_querycap(struct file *file, void *priv,
  * I2C Interface
  **************************************************************************/
 
+/*
+ * si470x_i2c_interrupt_work - rds processing function
+ */
+static void si470x_i2c_interrupt_work(struct work_struct *work)
+{
+	struct si470x_device *radio = container_of(work,
+			struct si470x_device, radio_work);
+	unsigned char regnr;
+	unsigned char blocknum;
+	unsigned short bler; /* rds block errors */
+	unsigned short rds;
+	unsigned char tmpbuf[3];
+	int retval = 0;
+
+	/* safety checks */
+	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
+		return;
+
+	/* Update RDS registers */
+	for (regnr = 0; regnr < RDS_REGISTER_NUM; regnr++) {
+		retval = si470x_get_register(radio, STATUSRSSI + regnr);
+		if (retval < 0)
+			return;
+	}
+
+	/* get rds blocks */
+	if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0)
+		/* No RDS group ready, better luck next time */
+		return;
+
+	for (blocknum = 0; blocknum < 4; blocknum++) {
+		switch (blocknum) {
+		default:
+			bler = (radio->registers[STATUSRSSI] &
+					STATUSRSSI_BLERA) >> 9;
+			rds = radio->registers[RDSA];
+			break;
+		case 1:
+			bler = (radio->registers[READCHAN] &
+					READCHAN_BLERB) >> 14;
+			rds = radio->registers[RDSB];
+			break;
+		case 2:
+			bler = (radio->registers[READCHAN] &
+					READCHAN_BLERC) >> 12;
+			rds = radio->registers[RDSC];
+			break;
+		case 3:
+			bler = (radio->registers[READCHAN] &
+					READCHAN_BLERD) >> 10;
+			rds = radio->registers[RDSD];
+			break;
+		};
+
+		/* Fill the V4L2 RDS buffer */
+		put_unaligned_le16(rds, &tmpbuf);
+		tmpbuf[2] = blocknum;		/* offset name */
+		tmpbuf[2] |= blocknum << 3;	/* received offset */
+		if (bler > max_rds_errors)
+			tmpbuf[2] |= 0x80;	/* uncorrectable errors */
+		else if (bler > 0)
+			tmpbuf[2] |= 0x40;	/* corrected error(s) */
+
+		/* copy RDS block to internal buffer */
+		memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
+		radio->wr_index += 3;
+
+		/* wrap write pointer */
+		if (radio->wr_index >= radio->buf_size)
+			radio->wr_index = 0;
+
+		/* check for overflow */
+		if (radio->wr_index == radio->rd_index) {
+			/* increment and wrap read pointer */
+			radio->rd_index += 3;
+			if (radio->rd_index >= radio->buf_size)
+				radio->rd_index = 0;
+		}
+	}
+
+	if (radio->wr_index != radio->rd_index)
+		wake_up_interruptible(&radio->read_queue);
+}
+
+
+/*
+ * si470x_i2c_interrupt - interrupt handler
+ */
+static irqreturn_t si470x_i2c_interrupt(int irq, void *dev_id)
+{
+	struct si470x_device *radio = dev_id;
+
+	if (!work_pending(&radio->radio_work))
+		schedule_work(&radio->radio_work);
+
+	return IRQ_HANDLED;
+}
+
+
 /*
  * si470x_i2c_probe - probe for the device
  */
@@ -257,6 +374,8 @@ static int __devinit si470x_i2c_probe(struct i2c_client *client,
 		retval = -ENOMEM;
 		goto err_initial;
 	}
+
+	INIT_WORK(&radio->radio_work, si470x_i2c_interrupt_work);
 	radio->users = 0;
 	radio->client = client;
 	mutex_init(&radio->lock);
@@ -308,6 +427,26 @@ static int __devinit si470x_i2c_probe(struct i2c_client *client,
 	/* set initial frequency */
 	si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */
 
+	/* rds buffer allocation */
+	radio->buf_size = rds_buf * 3;
+	radio->buffer = kmalloc(radio->buf_size, GFP_KERNEL);
+	if (!radio->buffer) {
+		retval = -EIO;
+		goto err_video;
+	}
+
+	/* rds buffer configuration */
+	radio->wr_index = 0;
+	radio->rd_index = 0;
+	init_waitqueue_head(&radio->read_queue);
+
+	retval = request_irq(client->irq, si470x_i2c_interrupt,
+			IRQF_TRIGGER_FALLING, DRIVER_NAME, radio);
+	if (retval) {
+		dev_err(&client->dev, "Failed to register interrupt\n");
+		goto err_rds;
+	}
+
 	/* register video device */
 	retval = video_register_device(radio->videodev, VFL_TYPE_RADIO,
 			radio_nr);
@@ -319,6 +458,9 @@ static int __devinit si470x_i2c_probe(struct i2c_client *client,
 
 	return 0;
 err_all:
+	free_irq(client->irq, radio);
+err_rds:
+	kfree(radio->buffer);
 err_video:
 	video_device_release(radio->videodev);
 err_radio:
@@ -335,6 +477,8 @@ static __devexit int si470x_i2c_remove(struct i2c_client *client)
 {
 	struct si470x_device *radio = i2c_get_clientdata(client);
 
+	free_irq(client->irq, radio);
+	cancel_work_sync(&radio->radio_work);
 	video_unregister_device(radio->videodev);
 	kfree(radio);
 	i2c_set_clientdata(client, NULL);

drivers/media/radio/si470x/radio-si470x.h

@@ -181,6 +181,7 @@ struct si470x_device {
 
 #if defined(CONFIG_I2C_SI470X) || defined(CONFIG_I2C_SI470X_MODULE)
 	struct i2c_client *client;
+	struct work_struct radio_work;
 #endif
 };