| Message ID | 1340338339-11626-14-git-send-email-troy.kisky@boundarydevices.com |
|---|---|
| State | Superseded |
| Delegated to: | Heiko Schocher |
| Headers | show |
Dear Troy Kisky, > Retry unexpected hardware errors. This > will not retry a received NAK. > > Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com> Why do you need this? Are you getting transmission errors? I think it's because you broke something in the driver, I was getting errors, but managed to hack it together in such a manner, that they didn't happen anymore. > --- > drivers/i2c/mxc_i2c.c | 36 +++++++++++++++++++++++++++--------- > 1 file changed, 27 insertions(+), 9 deletions(-) > > diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c > index df033ea..802f70f 100644 > --- a/drivers/i2c/mxc_i2c.c > +++ b/drivers/i2c/mxc_i2c.c > @@ -213,7 +213,7 @@ void i2c_imx_stop(void) > * Send start signal, chip address and > * write register address > */ > -static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, > +static int i2c_init_transfer_(struct mxc_i2c_regs *i2c_regs, > uchar chip, uint addr, int alen) > { > unsigned int temp; > @@ -230,7 +230,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs > *i2c_regs, writeb(0, &i2c_regs->i2sr); > ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); > if (ret < 0) > - goto exit; > + return ret; > > /* Start I2C transaction */ > temp = readb(&i2c_regs->i2cr); > @@ -239,7 +239,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs > *i2c_regs, > > ret = wait_for_sr_state(i2c_regs, ST_BUS_BUSY); > if (ret < 0) > - goto exit; > + return ret; > > temp |= I2CR_MTX | I2CR_TX_NO_AK; > writeb(temp, &i2c_regs->i2cr); > @@ -247,18 +247,36 @@ static int i2c_init_transfer(struct mxc_i2c_regs > *i2c_regs, /* write slave address */ > ret = tx_byte(i2c_regs, chip << 1); > if (ret < 0) > - goto exit; > + return ret; > > while (alen--) { > ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff); > if (ret < 0) > - goto exit; > + return ret; > } > return 0; > -exit: > - i2c_imx_stop(); > - /* Disable I2C controller */ > - writeb(0, &i2c_regs->i2cr); > +} > + > +static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, > + uchar chip, uint addr, int alen) > +{ > + int retry; > + int ret; > + for (retry = 0; retry < 3; retry++) { > + ret = i2c_init_transfer_(i2c_regs, chip, addr, alen); > + if (ret >= 0) > + return ret; > + i2c_imx_stop(i2c_regs); > + if (ret == -ENODEV) > + return ret; > + > + printf("%s: failed for chip 0x%x retry=%d\n", __func__, chip, > + retry); > + if (ret != -ERESTART) > + writeb(0, &i2c_regs->i2cr); /* Disable controller */ > + udelay(100); > + } > + printf("%s: give up i2c_regs=%p\n", __func__, i2c_regs); > return ret; > } Best regards, Marek Vasut
On 6/22/2012 10:06 AM, Marek Vasut wrote: > Dear Troy Kisky, > >> Retry unexpected hardware errors. This >> will not retry a received NAK. >> >> Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com> > Why do you need this? Are you getting transmission errors? I think it's because > you broke something in the driver, I was getting errors, but managed to hack it > together in such a manner, that they didn't happen anymore. I have an hdmi display that holds the SCL line low for ~3 seconds every ~9 seconds. I added this code while trying to debug that. Granted it is the display's fault, but bus recovery is important. >> --- >> drivers/i2c/mxc_i2c.c | 36 +++++++++++++++++++++++++++--------- >> 1 file changed, 27 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c >> index df033ea..802f70f 100644 >> --- a/drivers/i2c/mxc_i2c.c >> +++ b/drivers/i2c/mxc_i2c.c >> @@ -213,7 +213,7 @@ void i2c_imx_stop(void) >> * Send start signal, chip address and >> * write register address >> */ >> -static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, >> +static int i2c_init_transfer_(struct mxc_i2c_regs *i2c_regs, >> uchar chip, uint addr, int alen) >> { >> unsigned int temp; >> @@ -230,7 +230,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs >> *i2c_regs, writeb(0, &i2c_regs->i2sr); >> ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); >> if (ret < 0) >> - goto exit; >> + return ret; >> >> /* Start I2C transaction */ >> temp = readb(&i2c_regs->i2cr); >> @@ -239,7 +239,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs >> *i2c_regs, >> >> ret = wait_for_sr_state(i2c_regs, ST_BUS_BUSY); >> if (ret < 0) >> - goto exit; >> + return ret; >> >> temp |= I2CR_MTX | I2CR_TX_NO_AK; >> writeb(temp, &i2c_regs->i2cr); >> @@ -247,18 +247,36 @@ static int i2c_init_transfer(struct mxc_i2c_regs >> *i2c_regs, /* write slave address */ >> ret = tx_byte(i2c_regs, chip << 1); >> if (ret < 0) >> - goto exit; >> + return ret; >> >> while (alen--) { >> ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff); >> if (ret < 0) >> - goto exit; >> + return ret; >> } >> return 0; >> -exit: >> - i2c_imx_stop(); >> - /* Disable I2C controller */ >> - writeb(0, &i2c_regs->i2cr); >> +} >> + >> +static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, >> + uchar chip, uint addr, int alen) >> +{ >> + int retry; >> + int ret; >> + for (retry = 0; retry < 3; retry++) { >> + ret = i2c_init_transfer_(i2c_regs, chip, addr, alen); >> + if (ret >= 0) >> + return ret; >> + i2c_imx_stop(i2c_regs); >> + if (ret == -ENODEV) >> + return ret; >> + >> + printf("%s: failed for chip 0x%x retry=%d\n", __func__, chip, >> + retry); >> + if (ret != -ERESTART) >> + writeb(0, &i2c_regs->i2cr); /* Disable controller */ >> + udelay(100); >> + } >> + printf("%s: give up i2c_regs=%p\n", __func__, i2c_regs); >> return ret; >> } > Best regards, > Marek Vasut >
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c index df033ea..802f70f 100644 --- a/drivers/i2c/mxc_i2c.c +++ b/drivers/i2c/mxc_i2c.c @@ -213,7 +213,7 @@ void i2c_imx_stop(void) * Send start signal, chip address and * write register address */ -static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, +static int i2c_init_transfer_(struct mxc_i2c_regs *i2c_regs, uchar chip, uint addr, int alen) { unsigned int temp; @@ -230,7 +230,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, writeb(0, &i2c_regs->i2sr); ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); if (ret < 0) - goto exit; + return ret; /* Start I2C transaction */ temp = readb(&i2c_regs->i2cr); @@ -239,7 +239,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, ret = wait_for_sr_state(i2c_regs, ST_BUS_BUSY); if (ret < 0) - goto exit; + return ret; temp |= I2CR_MTX | I2CR_TX_NO_AK; writeb(temp, &i2c_regs->i2cr); @@ -247,18 +247,36 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, /* write slave address */ ret = tx_byte(i2c_regs, chip << 1); if (ret < 0) - goto exit; + return ret; while (alen--) { ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff); if (ret < 0) - goto exit; + return ret; } return 0; -exit: - i2c_imx_stop(); - /* Disable I2C controller */ - writeb(0, &i2c_regs->i2cr); +} + +static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, + uchar chip, uint addr, int alen) +{ + int retry; + int ret; + for (retry = 0; retry < 3; retry++) { + ret = i2c_init_transfer_(i2c_regs, chip, addr, alen); + if (ret >= 0) + return ret; + i2c_imx_stop(i2c_regs); + if (ret == -ENODEV) + return ret; + + printf("%s: failed for chip 0x%x retry=%d\n", __func__, chip, + retry); + if (ret != -ERESTART) + writeb(0, &i2c_regs->i2cr); /* Disable controller */ + udelay(100); + } + printf("%s: give up i2c_regs=%p\n", __func__, i2c_regs); return ret; }
Retry unexpected hardware errors. This will not retry a received NAK. Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com> --- drivers/i2c/mxc_i2c.c | 36 +++++++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 9 deletions(-)