On Mon, 30 Mar 2009, Wolfram Sang wrote:
> On Mon, Mar 30, 2009 at 03:50:28PM +0200, Guennadi Liakhovetski wrote:
>
> > Ok, I just was informed, that there is a hardware bug on the board I am
> > using. So, please ignore my objections. Sorry for the wasted time.
>
> Well, not completely wasted: We found a bug :) Patch follows, Ben can
> you add it?
>
> Regards,
>
> Wolfram
>
> ===
>
> 'disable_delay' was static which is wrong as it is calculated using the per-device
> bus speed. This patch turns 'disable_delay' into a per-device variable.
>
> Reported-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> Signed-off-by: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
Thanks
Guennadi
> ---
> drivers/i2c/busses/i2c-imx.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> Index: .kernel/drivers/i2c/busses/i2c-imx.c
> ===================================================================
> --- .kernel.orig/drivers/i2c/busses/i2c-imx.c
> +++ .kernel/drivers/i2c/busses/i2c-imx.c
> @@ -86,8 +86,6 @@
> /** Variables ******************************************************************
> *******************************************************************************/
>
> -static unsigned int disable_delay; /* Dummy delay */
> -
> /*
> * sorted list of clock divider, register value pairs
> * taken from table 26-5, p.26-9, Freescale i.MX
> @@ -121,6 +119,7 @@ struct imx_i2c_struct {
> int irq;
> wait_queue_head_t queue;
> unsigned long i2csr;
> + unsigned int disable_delay;
> };
>
> /** Functions for IMX I2C adapter driver ***************************************
> @@ -212,7 +211,7 @@ static void i2c_imx_stop(struct imx_i2c_
> * This delay caused by an i.MXL hardware bug.
> * If no (or too short) delay, no "STOP" bit will be generated.
> */
> - udelay(disable_delay);
> + udelay(i2c_imx->disable_delay);
> /* Disable I2C controller */
> writeb(0, i2c_imx->base + IMX_I2C_I2CR);
> }
> @@ -243,7 +242,7 @@ static void __init i2c_imx_set_clk(struc
> * This delay is used in I2C bus disable function
> * to fix chip hardware bug.
> */
> - disable_delay = (500000U * i2c_clk_div[i][0]
> + i2c_imx->disable_delay = (500000U * i2c_clk_div[i][0]
> + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
>
> /* dev_dbg() can't be used, because adapter is not yet registered */
>
> --
> Pengutronix e.K. | Wolfram Sang |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
>
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
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