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From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 14/24] mxc_i2c: add retries
Date: Fri, 22 Jun 2012 19:06:03 +0200	[thread overview]
Message-ID: <201206221906.03647.marex@denx.de> (raw)
In-Reply-To: <1340338339-11626-14-git-send-email-troy.kisky@boundarydevices.com>

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

  reply	other threads:[~2012-06-22 17:06 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-22  4:11 [U-Boot] [PATCH 01/24] mxc_i2c: fix i2c_imx_stop Troy Kisky
2012-06-22  4:11 ` [U-Boot] [PATCH 02/24] mxc_i2c: remove ifdef of CONFIG_HARD_I2C Troy Kisky
2012-06-22 16:55   ` Marek Vasut
2012-06-22  4:11 ` [U-Boot] [PATCH 03/24] mxc_i2c: create tx_byte function Troy Kisky
2012-06-22 16:58   ` Marek Vasut
2012-06-22 23:05     ` Troy Kisky
2012-06-23  1:51       ` Marek Vasut
2012-06-22  4:11 ` [U-Boot] [PATCH 04/24] mxc_i2c: clear i2sr before waiting for bit Troy Kisky
2012-06-22 16:59   ` Marek Vasut
2012-06-24  0:18     ` Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 05/24] mxc_i2c: create i2c_init_transfer Troy Kisky
2012-06-22 16:59   ` Marek Vasut
2012-06-24  8:06   ` Stefano Babic
2012-06-22  4:12 ` [U-Boot] [PATCH 06/24] mxc_i2c.c: code i2c_probe as a 0 length i2c_write Troy Kisky
2012-06-22 17:00   ` Marek Vasut
2012-06-24  8:03   ` Stefano Babic
2012-06-22  4:12 ` [U-Boot] [PATCH 07/24] mxc_i2c: combine i2c_imx_bus_busy and i2c_imx_trx_complete into wait_for_sr_state Troy Kisky
2012-06-22 17:01   ` Marek Vasut
2012-06-22 17:34     ` Troy Kisky
2012-06-22 18:01       ` Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 08/24] mxc_i2c: remove redundant read Troy Kisky
2012-06-22 17:02   ` Marek Vasut
2012-06-22  4:12 ` [U-Boot] [PATCH 09/24] mxc_i2c: place imx_start code inline Troy Kisky
2012-06-22 17:02   ` Marek Vasut
2012-06-22  4:12 ` [U-Boot] [PATCH 10/24] mxc_i2c: place i2c_reset " Troy Kisky
2012-06-22 17:03   ` Marek Vasut
2012-06-22  4:12 ` [U-Boot] [PATCH 11/24] mxc_i2c: don't disable controller after every transaction Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 12/24] mxc_i2c: change slave addr if conflicts with destination Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 13/24] mxc_i2c: check for arbitration lost Troy Kisky
2012-06-22 17:04   ` Marek Vasut
2012-06-22  4:12 ` [U-Boot] [PATCH 14/24] mxc_i2c: add retries Troy Kisky
2012-06-22 17:06   ` Marek Vasut [this message]
2012-06-22 17:40     ` Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 15/24] mxc_i2c: add i2c_regs argument to i2c_imx_stop Troy Kisky
2012-06-22 17:06   ` Marek Vasut
2012-06-22  4:12 ` [U-Boot] [PATCH 16/24] mxc_i2c: prep work for multiple busses support Troy Kisky
2012-06-22 17:08   ` Marek Vasut
2012-06-24  8:47   ` Heiko Schocher
2012-06-24 20:08     ` Marek Vasut
2012-06-24 22:09       ` Wolfgang Denk
2012-06-22  4:12 ` [U-Boot] [PATCH 17/24] mxc_i2c: add bus recovery support Troy Kisky
2012-06-24  8:51   ` Heiko Schocher
2012-06-26  3:42     ` Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 18/24] mxc_i2c.c: finish adding CONFIG_I2C_MULTI_BUS support Troy Kisky
2012-06-22 17:09   ` Marek Vasut
2012-06-22 19:41     ` Troy Kisky
2012-06-25  3:34       ` Tabi Timur-B04825
2012-06-22  4:12 ` [U-Boot] [PATCH 19/24] iomux-v3: remove include of mx6x_pins.h Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 20/24] i.mx: iomux-v3.h: move to imx-common include directory Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 21/24] i.mx: iomux-v3.c: move to imx-common directory Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 22/24] i.mx53: add definition for I2C3_BASE_ADDR Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 23/24] imx-common: add i2c.c for bus recovery support Troy Kisky
2012-06-22  4:12 ` [U-Boot] [PATCH 24/24] mx6qsabrelite: add i2c multi-bus support Troy Kisky
2012-06-22 16:55 ` [U-Boot] [PATCH 01/24] mxc_i2c: fix i2c_imx_stop Marek Vasut
2012-06-24  7:49 ` Stefano Babic

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