Re: [PATCH v1 04/63] Input: atmel_mxt_ts - split large i2c transfers into blocks

From: Dmitry Torokhov
Date: Fri Aug 16 2019 - 13:18:43 EST


On Fri, Aug 16, 2019 at 05:28:53PM +0900, Jiada Wang wrote:
> From: Nick Dyer <nick.dyer@xxxxxxxxxxx>
>
> On some firmware variants, the size of the info block exceeds what can
> be read in a single transfer.
>
> Signed-off-by: Nick Dyer <nick.dyer@xxxxxxxxxxx>
> (cherry picked from ndyer/linux/for-upstream commit 74c4f5277cfa403d43fafc404119dc57a08677db)
> [gdavis: Forward port and fix conflicts due to v4.14.51 commit
> 960fe000b1d3 ("Input: atmel_mxt_ts - fix the firmware
> update").]
> Signed-off-by: George G. Davis <george_davis@xxxxxxxxxx>
> Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
> ---
> drivers/input/touchscreen/atmel_mxt_ts.c | 27 +++++++++++++++++++++---
> 1 file changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 9b165d23e092..2d70ddf71cd9 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -40,7 +40,7 @@
> #define MXT_OBJECT_START 0x07
> #define MXT_OBJECT_SIZE 6
> #define MXT_INFO_CHECKSUM_SIZE 3
> -#define MXT_MAX_BLOCK_WRITE 256
> +#define MXT_MAX_BLOCK_WRITE 255
>
> /* Object types */
> #define MXT_DEBUG_DIAGNOSTIC_T37 37
> @@ -659,6 +659,27 @@ static int __mxt_read_reg(struct i2c_client *client,
> return ret;
> }
>
> +static int mxt_read_blks(struct mxt_data *data, u16 start, u16 count, u8 *buf)

Can we call this __mxt_read_reg() and the original read reg call
__mxt_read_chunk()?

> +{
> + u16 offset = 0;
> + int error;
> + u16 size;
> +
> + while (offset < count) {
> + size = min(MXT_MAX_BLOCK_WRITE, count - offset);
> +
> + error = __mxt_read_reg(data->client,
> + start + offset,
> + size, buf + offset);
> + if (error)
> + return error;
> +
> + offset += size;
> + }
> +
> + return 0;
> +}

Thanks.

--
Dmitry