Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5e3c5967 authored by Chris Pascoe's avatar Chris Pascoe Committed by Mauro Carvalho Chehab
Browse files

V4L/DVB (6857): cx23885: correctly join I2C writes and reads from same address 



When an I2C message specifies a write then a read from the same I2C address,
we need to tell the chip to not release the bus between the message parts.

Signed-off-by: default avatarChris Pascoe <c.pascoe@itee.uq.edu.au>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent bc514710

drivers/media/video/cx23885/cx23885-i2c.c

+39 −14
Original line number Diff line number Diff line
@@ -37,8 +37,10 @@ static unsigned int i2c_scan = 0; 
module_param(i2c_scan, int, 0444);

MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");



#define dprintk(level,fmt, arg...)	if (i2c_debug >= level) \

	printk(KERN_DEBUG "%s: " fmt, dev->name , ## arg)

#define dprintk(level, fmt, arg...)	do { \

	if (i2c_debug >= level) \

		printk(KERN_DEBUG "%s: " fmt, dev->name , ## arg); \

	} while (0)



#define I2C_WAIT_DELAY 32

#define I2C_WAIT_RETRY 64
@@ -77,14 +79,18 @@ static int i2c_wait_done(struct i2c_adapter *i2c_adap) 
}



static int i2c_sendbytes(struct i2c_adapter *i2c_adap,

			 const struct i2c_msg *msg, int last)

			 const struct i2c_msg *msg, int joined_rlen)

{

	struct cx23885_i2c *bus = i2c_adap->algo_data;

	struct cx23885_dev *dev = bus->dev;

	u32 wdata, addr, ctrl;

	int retval, cnt;



	dprintk(1, "%s(msg->len=%d, last=%d)\n", __FUNCTION__, msg->len, last);

	if (joined_rlen)

		dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __FUNCTION__,

			msg->len, joined_rlen);

	else

		dprintk(1, "%s(msg->len=%d)\n", __FUNCTION__, msg->len);



	/* Deal with i2c probe functions with zero payload */

	if (msg->len == 0) {
@@ -107,6 +113,8 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap, 


	if (msg->len > 1)

		ctrl |= I2C_NOSTOP | I2C_EXTEND;

	else if (joined_rlen)

		ctrl |= I2C_NOSTOP;



	cx_write(bus->reg_addr, addr);

	cx_write(bus->reg_wdata, wdata);
@@ -130,6 +138,8 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap, 


		if (cnt < msg->len - 1)

			ctrl |= I2C_NOSTOP | I2C_EXTEND;

		else if (joined_rlen)

			ctrl |= I2C_NOSTOP;



		cx_write(bus->reg_addr, addr);

		cx_write(bus->reg_wdata, wdata);
@@ -151,19 +161,22 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap, 
 eio:

	retval = -EIO;

 err:

	if (i2c_debug)

		printk(" ERR: %d\n", retval);

	return retval;

}



static int i2c_readbytes(struct i2c_adapter *i2c_adap,

			 const struct i2c_msg *msg, int last)

			 const struct i2c_msg *msg, int joined)

{

	struct cx23885_i2c *bus = i2c_adap->algo_data;

	struct cx23885_dev *dev = bus->dev;

	u32 ctrl, cnt;

	int retval;



	dprintk(1, "%s(msg->len=%d, last=%d)\n", __FUNCTION__, msg->len, last);



	if (i2c_debug && !joined)

		dprintk(1, "%s(msg->len=%d)\n", __FUNCTION__, msg->len);



	/* Deal with i2c probe functions with zero payload */

	if (msg->len == 0) {
@@ -179,8 +192,12 @@ static int i2c_readbytes(struct i2c_adapter *i2c_adap, 
		return 0;

	}



	if (i2c_debug)

	if (i2c_debug) {

		if (joined)

			printk(" R");

		else

			printk(" <R %02x", (msg->addr << 1) + 1);

	}



	for(cnt = 0; cnt < msg->len; cnt++) {
@@ -209,6 +226,7 @@ static int i2c_readbytes(struct i2c_adapter *i2c_adap, 
 eio:

	retval = -EIO;

 err:

	if (i2c_debug)

		printk(" ERR: %d\n", retval);

	return retval;

}
@@ -227,16 +245,23 @@ static int i2c_xfer(struct i2c_adapter *i2c_adap, 
			__FUNCTION__, num, msgs[i].addr, msgs[i].len);

		if (msgs[i].flags & I2C_M_RD) {

			/* read */

			retval = i2c_readbytes(i2c_adap, &msgs[i], i+1 == num);

			retval = i2c_readbytes(i2c_adap, &msgs[i], 0);

		} else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&

			   msgs[i].addr == msgs[i + 1].addr) {

			/* write then read from same address */

			retval = i2c_sendbytes(i2c_adap, &msgs[i],

					       msgs[i + 1].len);

			if (retval < 0)

				goto err;

			i++;

			retval = i2c_readbytes(i2c_adap, &msgs[i], 1);

		} else {

			/* write */

			retval = i2c_sendbytes(i2c_adap, &msgs[i], i+1 == num);

			retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);

		}

		if (retval < 0)

			goto err;

	}

	}

	return num;



 err: