On Thu, Jul 12, 2012 at 7:24 AM, Datta, Shubhrajyoti
<shubhrajyoti@xxxxxx> wrote:
> On Wed, Jul 11, 2012 at 10:22 PM, Shubhrajyoti <shubhrajyoti@xxxxxx> wrote:
>> On Wednesday 11 July 2012 09:53 PM, Yegor Yefremov wrote:
> [...]
> Yegor I have made a patch to ignore the NACK in the ISR let me know if
> that helps you.
>
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 9895fa7..e13061f 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -476,6 +476,8 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
>
> if (msg->len == 0)
> return -EINVAL;
> + if (msg->flags & I2C_M_IGNORE_NAK)
> + dev->flags |= OMAP_I2C_FLAG_NO_NAK;
>
> omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
>
> @@ -776,18 +778,26 @@ complete:
> ~(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
> OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
>
> - if (stat & OMAP_I2C_STAT_NACK)
> + if (stat & OMAP_I2C_STAT_NACK &&
> + !(dev->flags & OMAP_I2C_FLAG_NO_NAK)) {
> err |= OMAP_I2C_STAT_NACK;
> + omap_i2c_ack_stat(dev, stat &
> + (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
> + OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR |
> + OMAP_I2C_STAT_ARDY));
> + omap_i2c_complete_cmd(dev, err);
> + return IRQ_HANDLED;
> + }
>
> if (stat & OMAP_I2C_STAT_AL) {
> dev_err(dev->dev, "Arbitration lost\n");
> err |= OMAP_I2C_STAT_AL;
> }
> +
> /*
> * ProDB0017052: Clear ARDY bit twice
> */
> - if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
> - OMAP_I2C_STAT_AL)) {
> + if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_AL)) {
> omap_i2c_ack_stat(dev, stat &
> (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
> OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR |
> diff --git a/include/linux/i2c-omap.h b/include/linux/i2c-omap.h
> index 92a0dc7..f386150 100644
> --- a/include/linux/i2c-omap.h
> +++ b/include/linux/i2c-omap.h
> @@ -29,6 +29,7 @@
> #define OMAP_I2C_FLAG_BUS_SHIFT_1 BIT(7)
> #define OMAP_I2C_FLAG_BUS_SHIFT_2 BIT(8)
> #define OMAP_I2C_FLAG_BUS_SHIFT__SHIFT 7
> +#define OMAP_I2C_FLAG_NO_NAK BIT(9)
>
> struct omap_i2c_bus_platform_data {
> u32 clkrate;
Thank you for the patch and sorry for delay. I tried the patch, but it
doesn't help. I still get timeouts only. I fear it is really a
hardware feature, that OMAPs i2c stops if address is not acknowledged.
At least this is my understanding of the reference manual.
Here is the output from dmesg:
i2c i2c-2: master_xfer[0] W, addr=0x39, len=2
omap_i2c omap_i2c.2: addr: 0x0039, len: 2, flags: 0x0, stop: 1
omap_i2c omap_i2c.2: IRQ (ISR = 0x4000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x0004)
i2c i2c-2: master_xfer[0] W, addr=0x39, len=1
i2c i2c-2: master_xfer[1] R, addr=0x39, len=1
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x0, stop: 0
omap_i2c omap_i2c.2: IRQ (ISR = 0x4000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x1004)
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x1, stop: 1
omap_i2c omap_i2c.2: IRQ (ISR = 0x3000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x0004)
SIIHDMI: Device ID: 0xb0
i2c i2c-2: master_xfer[0] W, addr=0x39, len=1
i2c i2c-2: master_xfer[1] R, addr=0x39, len=1
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x0, stop: 0
omap_i2c omap_i2c.2: IRQ (ISR = 0x4000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x1004)
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x1, stop: 1
omap_i2c omap_i2c.2: IRQ (ISR = 0x3000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x0004)
(rev 0.2)
i2c i2c-2: master_xfer[0] W, addr=0x39, len=1
i2c i2c-2: master_xfer[1] R, addr=0x39, len=1
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x0, stop: 0
omap_i2c omap_i2c.2: IRQ (ISR = 0x4000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x1004)
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x1, stop: 1
omap_i2c omap_i2c.2: IRQ (ISR = 0x3000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x0004)
(TPI revision 0.3)
i2c i2c-2: master_xfer[0] W, addr=0x39, len=1
i2c i2c-2: master_xfer[1] R, addr=0x39, len=1
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x0, stop: 0
omap_i2c omap_i2c.2: IRQ (ISR = 0x4000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x1004)
omap_i2c omap_i2c.2: addr: 0x0039, len: 1, flags: 0x1, stop: 1
omap_i2c omap_i2c.2: IRQ (ISR = 0x3000)
omap_i2c omap_i2c.2: IRQ (ISR = 0x0004)
I have placed some debugging output:
SIIHDMI: Device ID: 0xb0
(rev 0.2)
(TPI revision 0.3)
YY: NAK should be ignored (here the flag will be set according to the msg->flag)
omap_i2c omap_i2c.2: controller timed out
YY: NAK should be ignored
omap_i2c omap_i2c.2: controller timed out
omap_i2c omap_i2c.2: controller timed out
YY: NAK should be ignored
omap_i2c omap_i2c.2: controller timed out
omap_i2c omap_i2c.2: controller timed out
omap_i2c omap_i2c.2: controller timed out
omap_i2c omap_i2c.2: controller timed out
Yegor
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