From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Fri, 22 Jun 2012 19:06:03 +0200 Subject: [U-Boot] [PATCH 14/24] mxc_i2c: add retries In-Reply-To: <1340338339-11626-14-git-send-email-troy.kisky@boundarydevices.com> References: <1340338339-11626-1-git-send-email-troy.kisky@boundarydevices.com> <1340338339-11626-14-git-send-email-troy.kisky@boundarydevices.com> Message-ID: <201206221906.03647.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Dear Troy Kisky, > Retry unexpected hardware errors. This > will not retry a received NAK. > > Signed-off-by: Troy Kisky 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