If there are no comments for this patch, can you please consider this patch
for upstream?
-Manjunath
> -----Original Message-----
> From: G, Manjunath Kondaiah
> Sent: Friday, December 11, 2009 11:09 AM
> To: linux-omap@xxxxxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx;
> ben-linux@xxxxxxxxx
> Cc: G, Manjunath Kondaiah; Menon, Nishanth; Sonasath, Moiz;
> Krishnamoorthy, Balaji T; Varadarajan, Charu Latha; George, Harith
> Subject: [PATCH v2] OMAP3 : Fix I2C lockup during timeout/error cases
>
> Current OMAP3 I2C driver code does not follow the correct
> sequence for soft
> reset. Due to this, lock up issues are reported during
> timeout/error cases.
>
> This patch fixes above issue by disabling I2C controller as
> per OMAP3430 TRM
> for soft reset. As per TRM, I2C controller needs to be
> disabled as a first
> step during soft reset.
>
> Here is correct soft reset sequence:
> a. Ensure that the module is disabled
> (clear the I2Ci.I2C_CON[15] I2C_EN bit to 0).
> b. Set the I2Ci.I2C_SYSC[1] SRST bit to 1.
> c. Enable the module by setting I2Ci.I2C_CON[15] I2C_EN bit to 1.
> d. Check the I2Ci.I2C_SYSS[0] RDONE bit until it is set to 1 to
> indicate the software reset is complete.
>
>
> Tested on Zoom2, Zoom3, 3430SDP and 3630SDP
>
> Signed-off-by: Manjunatha GK <manjugk@xxxxxx>
> Signed-off-by: George, Harith<harith@xxxxxx>
> Acked-by: Varadarajan, Charu Latha<charu@xxxxxx>
> ---
> v1 : Initital version
> v2 : Removed delay since time taken for disabling I2C
> controller is zero
> jiffies
>
> drivers/i2c/busses/i2c-omap.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-omap.c
> b/drivers/i2c/busses/i2c-omap.c
> index 827da08..74620c0 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -265,6 +265,11 @@ static int omap_i2c_init(struct
> omap_i2c_dev *dev)
> unsigned long internal_clk = 0;
>
> if (dev->rev >= OMAP_I2C_REV_2) {
> + /* Disable I2C controller before soft reset */
> + omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
> + omap_i2c_read_reg(dev, OMAP_I2C_CON_REG) &
> + ~(OMAP_I2C_CON_EN));
> +
> omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
> SYSC_SOFTRESET_MASK);
> /* For some reason we need to set the EN bit before the
> * reset done bit gets set. */
> --
> 1.6.0.4
>
> --
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
