Chip uses WRITE + STOP + READ + STOP sequence for I2C register read.
Driver was using REPEATED START condition which makes it failing if
I2C adapter was implemented correctly.
Add use_broken_read_reg_intentionally option to keep old buggy
implantation as there is buggy I2C adapter implementation relying
that bug...
Signed-off-by: Antti Palosaari <crope@xxxxxx>
---
drivers/media/tuners/mxl5007t.c | 56 ++++++++++++++++++++++++++++-
drivers/media/tuners/mxl5007t.h | 7 ++++
drivers/media/usb/au0828/au0828-dvb.c | 1 +
drivers/media/usb/dvb-usb-v2/af9015.c | 1 +
drivers/media/usb/dvb-usb-v2/af9035.c | 2 ++
drivers/media/usb/dvb-usb/dib0700_devices.c | 1 +
6 files changed, 67 insertions(+), 1 deletion(-)
diff --git a/drivers/media/tuners/mxl5007t.c b/drivers/media/tuners/mxl5007t.c
index 69e453e..36605ea 100644
--- a/drivers/media/tuners/mxl5007t.c
+++ b/drivers/media/tuners/mxl5007t.c
@@ -156,6 +156,7 @@ struct mxl5007t_state {
struct tuner_i2c_props i2c_props;
struct mutex lock;
+ struct mutex i2c_lock;
struct mxl5007t_config *config;
@@ -490,7 +491,8 @@ static int mxl5007t_write_regs(struct mxl5007t_state *state,
return ret;
}
-static int mxl5007t_read_reg(struct mxl5007t_state *state, u8 reg, u8 *val)
+/* XXX: bad implementation for avoiding regressions */
+static int mxl5007t_read_reg_bad(struct mxl5007t_state *state, u8 reg, u8 *val)
{
u8 buf[2] = { 0xfb, reg };
struct i2c_msg msg[] = {
@@ -509,6 +511,57 @@ static int mxl5007t_read_reg(struct mxl5007t_state *state, u8 reg, u8 *val)
return 0;
}
+/* chip uses I2C write + read with STOP condition */
+static int mxl5007t_read_reg_good(struct mxl5007t_state *state, u8 reg, u8 *val)
+{
+ int ret;
+ u8 buf[2] = { 0xfb, reg };
+ struct i2c_msg msg1[] = {
+ {
+ .addr = state->i2c_props.addr,
+ .flags = 0,
+ .buf = buf,
+ .len = 2,
+ },
+ };
+ struct i2c_msg msg2[] = {
+ {
+ .addr = state->i2c_props.addr,
+ .flags = I2C_M_RD,
+ .buf = val,
+ .len = 1,
+ },
+ };
+
+ mutex_lock(&state->i2c_lock);
+
+ ret = i2c_transfer(state->i2c_props.adap, msg1, 1);
+ if (ret != 1) {
+ mxl_err("failed!");
+ ret = -EREMOTEIO;
+ goto fail;
+ }
+
+ ret = i2c_transfer(state->i2c_props.adap, msg2, 1);
+ if (ret != 1) {
+ mxl_err("failed!");
+ ret = -EREMOTEIO;
+ goto fail;
+ }
+fail:
+ mutex_unlock(&state->i2c_lock);
+
+ return ret;
+}
+
+static int mxl5007t_read_reg(struct mxl5007t_state *state, u8 reg, u8 *val)
+{
+ if (state->config->use_broken_read_reg_intentionally)
+ return mxl5007t_read_reg_bad(state, reg, val);
+ else
+ return mxl5007t_read_reg_good(state, reg, val);
+}
+
static int mxl5007t_soft_reset(struct mxl5007t_state *state)
{
u8 d = 0xff;
@@ -883,6 +936,7 @@ struct dvb_frontend *mxl5007t_attach(struct dvb_frontend *fe,
state->config = cfg;
mutex_init(&state->lock);
+ mutex_init(&state->i2c_lock);
if (fe->ops.i2c_gate_ctrl)
fe->ops.i2c_gate_ctrl(fe, 1);
diff --git a/drivers/media/tuners/mxl5007t.h b/drivers/media/tuners/mxl5007t.h
index 37b0942..728779b 100644
--- a/drivers/media/tuners/mxl5007t.h
+++ b/drivers/media/tuners/mxl5007t.h
@@ -75,6 +75,13 @@ struct mxl5007t_config {
unsigned int invert_if:1;
unsigned int loop_thru_enable:1;
unsigned int clk_out_enable:1;
+ /*
+ * XXX: This should not be used. Defined for avoiding regressions.
+ * Remove use of that option after device is tested to be working with
+ * correct implementation.
+ * MxL5007t does not use I2C REPEATED START condition for register read.
+ */
+ unsigned int use_broken_read_reg_intentionally:1;
};
#if IS_ENABLED(CONFIG_MEDIA_TUNER_MXL5007T)
diff --git a/drivers/media/usb/au0828/au0828-dvb.c b/drivers/media/usb/au0828/au0828-dvb.c
index 9a6f156..7d32a0c 100644
--- a/drivers/media/usb/au0828/au0828-dvb.c
+++ b/drivers/media/usb/au0828/au0828-dvb.c
@@ -95,6 +95,7 @@ static struct xc5000_config hauppauge_xc5000c_config = {
static struct mxl5007t_config mxl5007t_hvr950q_config = {
.xtal_freq_hz = MxL_XTAL_24_MHZ,
.if_freq_hz = MxL_IF_6_MHZ,
+ .use_broken_read_reg_intentionally = 1,
};
static struct tda18271_config hauppauge_woodbury_tunerconfig = {
diff --git a/drivers/media/usb/dvb-usb-v2/af9015.c b/drivers/media/usb/dvb-usb-v2/af9015.c
index d556042..b943304 100644
--- a/drivers/media/usb/dvb-usb-v2/af9015.c
+++ b/drivers/media/usb/dvb-usb-v2/af9015.c
@@ -931,6 +931,7 @@ static struct tda18218_config af9015_tda18218_config = {
static struct mxl5007t_config af9015_mxl5007t_config = {
.xtal_freq_hz = MxL_XTAL_24_MHZ,
.if_freq_hz = MxL_IF_4_57_MHZ,
+ .use_broken_read_reg_intentionally = 1,
};
static int af9015_tuner_attach(struct dvb_usb_adapter *adap)
diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
index b638fc1..b7e7135 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -947,6 +947,7 @@ static struct mxl5007t_config af9035_mxl5007t_config[] = {
.loop_thru_enable = 0,
.clk_out_enable = 0,
.clk_out_amp = MxL_CLKOUT_AMP_0_94V,
+ .use_broken_read_reg_intentionally = 1,
}, {
.xtal_freq_hz = MxL_XTAL_24_MHZ,
.if_freq_hz = MxL_IF_4_57_MHZ,
@@ -954,6 +955,7 @@ static struct mxl5007t_config af9035_mxl5007t_config[] = {
.loop_thru_enable = 1,
.clk_out_enable = 1,
.clk_out_amp = MxL_CLKOUT_AMP_0_94V,
+ .use_broken_read_reg_intentionally = 1,
}
};
diff --git a/drivers/media/usb/dvb-usb/dib0700_devices.c b/drivers/media/usb/dvb-usb/dib0700_devices.c
index 1179842..c58c6ea 100644
--- a/drivers/media/usb/dvb-usb/dib0700_devices.c
+++ b/drivers/media/usb/dvb-usb/dib0700_devices.c
@@ -3433,6 +3433,7 @@ static struct mxl5007t_config hcw_mxl5007t_config = {
.xtal_freq_hz = MxL_XTAL_25_MHZ,
.if_freq_hz = MxL_IF_6_MHZ,
.invert_if = 1,
+ .use_broken_read_reg_intentionally = 1,
};
/* TIGER-ATSC map:
--
1.7.11.7
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
