Re: [PATCH] i2c: at91: Fix driver for SAMA5D2 SoC

[Alexander Shiyan <eagle.alexander923@gmail.com>]

Hello.

Please discard this patch aside for a while. I'll check it again.

Thanks!

пт, 10 янв. 2025 г. в 13:28, Alexander Shiyan <eagle.alexander923@gmail.com>:
>
> The current driver version does not work for me on SAMA5D2 SOC.
> I2C bus devices probing always returns good state, and as a result all
> addresses 0x01-0x7f are always present.
> After a some digging into the driver, I found that the NACK bit is not
> handled correctly. I also found another SAMA5D2-related patch in the kernel
> tree (1).
> The result is a complex patch for correct I2C bus operation on SAMA5D2 SOC.
>
> [1] https://squing.com/lander/squing.com/?l=linux-i2c&m=156382173106314&w=3&_=%2F%23wXPKnebvZEv31W5L%2FkOlGQ%3D%3D
>
> Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
> ---
>  drivers/i2c/busses/i2c-at91.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
> index dbc5aa4ddf..fb0a922a62 100644
> --- a/drivers/i2c/busses/i2c-at91.c
> +++ b/drivers/i2c/busses/i2c-at91.c
> @@ -113,7 +113,8 @@ static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
>  static void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
>  {
>         at91_twi_write(dev, AT91_TWI_IDR,
> -                      AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY);
> +                      AT91_TWI_TXCOMP | AT91_TWI_RXRDY |
> +                      AT91_TWI_TXRDY | AT91_TWI_NACK);
>  }
>
>  static void at91_init_twi_bus(struct at91_twi_dev *dev)
> @@ -223,8 +224,10 @@ static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
>         at91_twi_write(dev, AT91_TWI_THR, *dev->buf);
>
>         /* send stop when last byte has been written */
> -       if (--dev->buf_len == 0)
> +       if (--dev->buf_len == 0) {
>                 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
> +               at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_TXRDY);
> +       }
>
>         dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len);
>
> @@ -276,7 +279,7 @@ static int at91_twi_wait_completion(struct at91_twi_dev *dev)
>
>                 dev->transfer_status |= status;
>
> -       } while (!(at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_TXCOMP));
> +       } while (!(status & AT91_TWI_TXCOMP));
>
>         at91_disable_twi_interrupts(dev);
>
> @@ -311,11 +314,12 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
>                 at91_twi_write(dev, AT91_TWI_CR, start_flags);
>
>                 at91_twi_write(dev, AT91_TWI_IER,
> -                           AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
> +                           AT91_TWI_TXCOMP | AT91_TWI_NACK | AT91_TWI_RXRDY);
>         } else {
>                 at91_twi_write_next_byte(dev);
>                 at91_twi_write(dev, AT91_TWI_IER,
> -                           AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
> +                              AT91_TWI_TXCOMP | AT91_TWI_NACK |
> +                              (dev->buf_len ? AT91_TWI_TXRDY : 0));
>         }
>
>         ret = at91_twi_wait_completion(dev);
> --
> 2.39.1
>