From: Mauro Carvalho Chehab <mchehab@redhat.com>
Date: Sat, 9 Jul 2011 22:36:11 +0000 (-0300)
Subject: [media] em28xx-i2c: Add a read after I2C write
X-Git-Tag: v3.1-rc1~116^2~98
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=bbc70e647b04dc3df1c879089a4f6b633c1952c9;p=platform%2Fkernel%2Flinux-3.10.git

[media] em28xx-i2c: Add a read after I2C write

All I2C logs we got for em28xx does that. With Terratec H5, at
400MHz speed, it seems that this is required, to avoid having
troubles at the I2C bus.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---

diff --git a/drivers/media/video/em28xx/em28xx-i2c.c b/drivers/media/video/em28xx/em28xx-i2c.c
index 548d2df..36f5a9b 100644
--- a/drivers/media/video/em28xx/em28xx-i2c.c
+++ b/drivers/media/video/em28xx/em28xx-i2c.c
@@ -181,16 +181,25 @@ static int em2800_i2c_recv_bytes(struct em28xx *dev, unsigned char addr,
 
 /*
  * em28xx_i2c_send_bytes()
- * untested for more than 4 bytes
  */
 static int em28xx_i2c_send_bytes(void *data, unsigned char addr, char *buf,
 				 short len, int stop)
 {
 	int wrcount = 0;
 	struct em28xx *dev = (struct em28xx *)data;
+	int write_timeout, ret;
 
 	wrcount = dev->em28xx_write_regs_req(dev, stop ? 2 : 3, addr, buf, len);
 
+	/* Seems to be required after a write */
+	for (write_timeout = EM2800_I2C_WRITE_TIMEOUT; write_timeout > 0;
+	     write_timeout -= 5) {
+		ret = dev->em28xx_read_reg(dev, 0x05);
+		if (!ret)
+			break;
+		msleep(5);
+	}
+
 	return wrcount;
 }