linux/drivers/media/dvb/b2c2/flexcop-i2c.c

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/*
* This file is part of linux driver the digital TV devices equipped with B2C2 FlexcopII(b)/III
*
* flexcop-i2c.c - flexcop internal 2Wire bus (I2C) and dvb i2c initialization
*
* see flexcop.c for copyright information.
*/
#include "flexcop.h"
#define FC_MAX_I2C_RETRIES 100000
static int flexcop_i2c_operation(struct flexcop_device *fc, flexcop_ibi_value *r100)
{
int i;
flexcop_ibi_value r;
r100->tw_sm_c_100.working_start = 1;
deb_i2c("r100 before: %08x\n",r100->raw);
fc->write_ibi_reg(fc, tw_sm_c_100, ibi_zero);
fc->write_ibi_reg(fc, tw_sm_c_100, *r100); /* initiating i2c operation */
for (i = 0; i < FC_MAX_I2C_RETRIES; i++) {
r = fc->read_ibi_reg(fc, tw_sm_c_100);
if (!r.tw_sm_c_100.no_base_addr_ack_error) {
if (r.tw_sm_c_100.st_done) { /* && !r.tw_sm_c_100.working_start */
*r100 = r;
deb_i2c("i2c success\n");
return 0;
}
} else {
deb_i2c("suffering from an i2c ack_error\n");
return -EREMOTEIO;
}
}
deb_i2c("tried %d times i2c operation, never finished or too many ack errors.\n",i);
return -EREMOTEIO;
}
static int flexcop_i2c_read4(struct flexcop_device *fc, flexcop_ibi_value r100, u8 *buf)
{
flexcop_ibi_value r104;
int len = r100.tw_sm_c_100.total_bytes, /* remember total_bytes is buflen-1 */
ret;
if ((ret = flexcop_i2c_operation(fc,&r100)) != 0) {
/* The Cablestar needs a different kind of i2c-transfer (does not
* support "Repeat Start"):
* wait for the ACK failure,
* and do a subsequent read with the Bit 30 enabled
*/
r100.tw_sm_c_100.no_base_addr_ack_error = 1;
if ((ret = flexcop_i2c_operation(fc,&r100)) != 0) {
deb_i2c("no_base_addr read failed. %d\n",ret);
return ret;
}
}
buf[0] = r100.tw_sm_c_100.data1_reg;
if (len > 0) {
r104 = fc->read_ibi_reg(fc,tw_sm_c_104);
deb_i2c("read: r100: %08x, r104: %08x\n",r100.raw,r104.raw);
/* there is at least one more byte, otherwise we wouldn't be here */
buf[1] = r104.tw_sm_c_104.data2_reg;
if (len > 1) buf[2] = r104.tw_sm_c_104.data3_reg;
if (len > 2) buf[3] = r104.tw_sm_c_104.data4_reg;
}
return 0;
}
static int flexcop_i2c_write4(struct flexcop_device *fc, flexcop_ibi_value r100, u8 *buf)
{
flexcop_ibi_value r104;
int len = r100.tw_sm_c_100.total_bytes; /* remember total_bytes is buflen-1 */
r104.raw = 0;
/* there is at least one byte, otherwise we wouldn't be here */
r100.tw_sm_c_100.data1_reg = buf[0];
r104.tw_sm_c_104.data2_reg = len > 0 ? buf[1] : 0;
r104.tw_sm_c_104.data3_reg = len > 1 ? buf[2] : 0;
r104.tw_sm_c_104.data4_reg = len > 2 ? buf[3] : 0;
deb_i2c("write: r100: %08x, r104: %08x\n",r100.raw,r104.raw);
/* write the additional i2c data before doing the actual i2c operation */
fc->write_ibi_reg(fc,tw_sm_c_104,r104);
return flexcop_i2c_operation(fc,&r100);
}
int flexcop_i2c_request(struct flexcop_device *fc, flexcop_access_op_t op,
flexcop_i2c_port_t port, u8 chipaddr, u8 addr, u8 *buf, u16 len)
{
int ret;
u16 bytes_to_transfer;
flexcop_ibi_value r100;
deb_i2c("op = %d\n",op);
r100.raw = 0;
r100.tw_sm_c_100.chipaddr = chipaddr;
r100.tw_sm_c_100.twoWS_rw = op;
r100.tw_sm_c_100.twoWS_port_reg = port;
while (len != 0) {
bytes_to_transfer = len > 4 ? 4 : len;
r100.tw_sm_c_100.total_bytes = bytes_to_transfer - 1;
r100.tw_sm_c_100.baseaddr = addr;
if (op == FC_READ)
ret = flexcop_i2c_read4(fc, r100, buf);
else
ret = flexcop_i2c_write4(fc,r100, buf);
if (ret < 0)
return ret;
buf += bytes_to_transfer;
addr += bytes_to_transfer;
len -= bytes_to_transfer;
};
return 0;
}
/* exported for PCI i2c */
EXPORT_SYMBOL(flexcop_i2c_request);
/* master xfer callback for demodulator */
static int flexcop_master_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
{
struct flexcop_device *fc = i2c_get_adapdata(i2c_adap);
int i, ret = 0;
V4L/DVB (6042): b2c2-flexcop: fix Airstar HD5000 tuning regression Git changeset 6bdcc6e6dbab8daffd05e5026486f34ba41a6c72 dropped the stand-alone lgh06xf module, whose functionality was absorbed into the dvb-pll module. However, there was a minor difference between the code in lgh06xf and dvb-pll, which caused a regression in b2c2-flexcop devices using the LG-H06xF NIM. dvb-pll will probe for the presence of an i2c pll chip by performing a single byte read, the lgh06xf driver did not do this. Unfortunately, the code in flexcop-i2c.c does not currently support 1 byte or 0 byte reads as a probe. Such probes with the current code will always fail. In order to work around this problem, and restore proper functionality of the Airstar HD5000 device, this hack was created to make the probe appear to succeed. The single byte read in dvb_pll_attach is the only place where such a probe would ever occur, so this change is safe, and will not affect any other devices. Of course, if one knew how to actually perform the read operation, it would be better to go that route. In the meantime, however, we must apply this workaround, in order to prevent the regression that causes tuning to fail on the Airstar HD5000 ATSC device. Thanks to Jarod Wilson, who had originally reported this regression, and to Geoffrey Hausheer, whose original workaround patch led us to find the actual cause of the problem. Signed-off-by: Trent Piepho <xyzzy@speakeasy.org> Cc: Geoffrey Hausheer <inli3epy93n@phracturedblue.com> Acked-by: Jarod Wilson <jwilson@redhat.com> Signed-off-by: Michael Krufky <mkrufky@linuxtv.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
2007-08-19 08:05:54 +00:00
/* Some drivers use 1 byte or 0 byte reads as probes, which this
* driver doesn't support. These probes will always fail, so this
* hack makes them always succeed. If one knew how, it would of
* course be better to actually do the read. */
if (num == 1 && msgs[0].flags == I2C_M_RD && msgs[0].len <= 1)
return 1;
if (mutex_lock_interruptible(&fc->i2c_mutex))
return -ERESTARTSYS;
/* reading */
if (num == 2 &&
msgs[0].flags == 0 &&
msgs[1].flags == I2C_M_RD &&
msgs[0].buf != NULL &&
msgs[1].buf != NULL) {
ret = fc->i2c_request(fc, FC_READ, FC_I2C_PORT_DEMOD, msgs[0].addr, msgs[0].buf[0], msgs[1].buf, msgs[1].len);
} else for (i = 0; i < num; i++) { /* writing command */
if (msgs[i].flags != 0 || msgs[i].buf == NULL || msgs[i].len < 2) {
ret = -EINVAL;
break;
}
ret = fc->i2c_request(fc, FC_WRITE, FC_I2C_PORT_DEMOD, msgs[i].addr, msgs[i].buf[0], &msgs[i].buf[1], msgs[i].len - 1);
}
if (ret < 0)
err("i2c master_xfer failed");
else
ret = num;
mutex_unlock(&fc->i2c_mutex);
return ret;
}
static u32 flexcop_i2c_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C;
}
static struct i2c_algorithm flexcop_algo = {
.master_xfer = flexcop_master_xfer,
.functionality = flexcop_i2c_func,
};
int flexcop_i2c_init(struct flexcop_device *fc)
{
int ret;
mutex_init(&fc->i2c_mutex);
memset(&fc->i2c_adap, 0, sizeof(struct i2c_adapter));
strncpy(fc->i2c_adap.name, "B2C2 FlexCop device",
sizeof(fc->i2c_adap.name));
i2c_set_adapdata(&fc->i2c_adap,fc);
fc->i2c_adap.class = I2C_CLASS_TV_DIGITAL;
fc->i2c_adap.algo = &flexcop_algo;
fc->i2c_adap.algo_data = NULL;
fc->i2c_adap.dev.parent = fc->dev;
if ((ret = i2c_add_adapter(&fc->i2c_adap)) < 0)
return ret;
fc->init_state |= FC_STATE_I2C_INIT;
return 0;
}
void flexcop_i2c_exit(struct flexcop_device *fc)
{
if (fc->init_state & FC_STATE_I2C_INIT)
i2c_del_adapter(&fc->i2c_adap);
fc->init_state &= ~FC_STATE_I2C_INIT;
}