Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

V4L/DVB (6633): xc2028: make register reads atomic

Browse source 
Issuing register reads as a separate address write and data read transactions
means that other I2C activity could occur in between and state could get out
of sync.  Issue both the write and read in a single transaction so that the
i2c layer can prevent other users accessing the bus until we are complete.

Signed-off-by: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Chris Pascoe 2007-11-19 04:31:58 -03:00 committed by Mauro Carvalho Chehab
parent e155d908f7
commit 7d58d1117e
2 changed files with 43 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
drivers/media/video/tuner-i2c.h
View file

@ -46,6 +46,19 @@ static inline int tuner_i2c_xfer_recv(struct tuner_i2c_props *props, char *buf,
return (ret == 1) ? len : ret;
}
static inline int tuner_i2c_xfer_send_recv(struct tuner_i2c_props *props,
char *obuf, int olen,
char *ibuf, int ilen)
{
struct i2c_msg msg[2] = { { .addr = props->addr, .flags = 0,
.buf = obuf, .len = olen },
{ .addr = props->addr, .flags = I2C_M_RD,
.buf = ibuf, .len = ilen } };
int ret = i2c_transfer(props->adap, msg, 2);
return (ret == 2) ? ilen : ret;
}
#ifndef __TUNER_DRIVER_H__
#define tuner_warn(fmt, arg...) do { \
printk(KERN_WARNING "%s %d-%04x: " fmt, PREFIX, \

55
drivers/media/video/tuner-xc2028.c
View file

@ -101,6 +101,16 @@ struct xc2028_data {
_rc; \
})
#define i2c_send_recv(priv, obuf, osize, ibuf, isize) ({ \
int _rc; \
_rc = tuner_i2c_xfer_send_recv(&priv->i2c_props, obuf, osize, \
ibuf, isize); \
if (isize != _rc) \
tuner_err("i2c input error: rc = %d (should be %d)\n", \
_rc, (int)isize); \
_rc; \
})
#define send_seq(priv, data...) ({ \
static u8 _val[] = data; \
int _rc; \
@ -113,25 +123,21 @@ struct xc2028_data {
_rc; \
})
static unsigned int xc2028_get_reg(struct xc2028_data *priv, u16 reg)
static unsigned int xc2028_get_reg(struct xc2028_data *priv, u16 reg, u16 *val)
{
int rc;
unsigned char buf[2];
unsigned char ibuf[2];
tuner_dbg("%s called\n", __FUNCTION__);
tuner_dbg("%s %04x called\n", __FUNCTION__, reg);
buf[0] = reg>>8;
buf[0] = reg >> 8;
buf[1] = (unsigned char) reg;
rc = i2c_send(priv, buf, 2);
if (rc < 0)
return rc;
if (i2c_send_recv(priv, buf, 2, ibuf, 2) != 2)
return -EIO;
rc = i2c_rcv(priv, buf, 2);
if (rc < 0)
return rc;
return (buf[1]) | (buf[0] << 8);
*val = (ibuf[1]) | (ibuf[0] << 8);
return 0;
}
void dump_firm_type(unsigned int type)
@ -567,7 +573,8 @@ static int check_firmware(struct dvb_frontend *fe, enum tuner_mode new_mode,
v4l2_std_id std, fe_bandwidth_t bandwidth)
{
struct xc2028_data *priv = fe->tuner_priv;
int rc, version, hwmodel;
int rc;
u16 version, hwmodel;
v4l2_std_id std0 = 0;
unsigned int type0 = 0, type = 0;
int change_digital_bandwidth;
@ -692,8 +699,8 @@ static int check_firmware(struct dvb_frontend *fe, enum tuner_mode new_mode,
rc = load_scode(fe, type, &std, 0);
version = xc2028_get_reg(priv, 0x0004);
hwmodel = xc2028_get_reg(priv, 0x0008);
xc2028_get_reg(priv, 0x0004, &version);
xc2028_get_reg(priv, 0x0008, &hwmodel);
tuner_info("Device is Xceive %d version %d.%d, "
"firmware version %d.%d\n",
@ -708,33 +715,31 @@ static int check_firmware(struct dvb_frontend *fe, enum tuner_mode new_mode,
static int xc2028_signal(struct dvb_frontend *fe, u16 *strength)
{
struct xc2028_data *priv = fe->tuner_priv;
int frq_lock, signal = 0;
u16 frq_lock, signal = 0;
int rc;
tuner_dbg("%s called\n", __FUNCTION__);
mutex_lock(&priv->lock);
*strength = 0;
/* Sync Lock Indicator */
frq_lock = xc2028_get_reg(priv, 0x0002);
if (frq_lock <= 0)
rc = xc2028_get_reg(priv, 0x0002, &frq_lock);
if (rc < 0 || frq_lock == 0)
goto ret;
/* Frequency is locked. Return signal quality */
/* Get SNR of the video signal */
signal = xc2028_get_reg(priv, 0x0040);
if (signal <= 0)
signal = frq_lock;
rc = xc2028_get_reg(priv, 0x0040, &signal);
if (rc < 0)
signal = -frq_lock;
ret:
mutex_unlock(&priv->lock);
*strength = signal;
return 0;
return rc;
}
#define DIV 15625