Re: [PATCH v2] Input: wacom_i2c - Clean up the query device fields

Dmitry Torokhov
2024-06-06T21:23:28Z

Hi Alistair,

On Thu, Nov 18, 2021 at 10:35:45PM +1000, Alistair Francis wrote:
> Improve the query device fields to be more verbose.
>
> Signed-off-by: Alistair Francis <alistair@alistair23.me>

Could you please list what has changed since v1?

> ---
> drivers/input/touchscreen/wacom_i2c.c | 45 ++++++++++++++++-----------
> 1 file changed, 27 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/input/touchscreen/wacom_i2c.c b/drivers/input/touchscreen/wacom_i2c.c
> index fe4ea6204a4e..50d159919bd1 100644
> --- a/drivers/input/touchscreen/wacom_i2c.c
> +++ b/drivers/input/touchscreen/wacom_i2c.c
> @@ -23,13 +23,20 @@
> #define WACOM_BARREL_SWITCH_2 BIT(4)
> #define WACOM_IN_PROXIMITY BIT(5)
>
> -/* Registers */
> -#define WACOM_CMD_QUERY0 0x04
> -#define WACOM_CMD_QUERY1 0x00
> -#define WACOM_CMD_QUERY2 0x33
> -#define WACOM_CMD_QUERY3 0x02
> -#define WACOM_CMD_THROW0 0x05
> -#define WACOM_CMD_THROW1 0x00
> +// Registers

I am partial to C-style comments, let's keep them.

> +#define WACOM_COMMAND_LSB 0x04
> +#define WACOM_COMMAND_MSB 0x00
> +
> +#define WACOM_DATA_LSB 0x05
> +#define WACOM_DATA_MSB 0x00
> +
> +// Report types
> +#define REPORT_FEATURE 0x30
> +
> +// Requests / operations
> +#define OPCODE_GET_REPORT 0x02
> +
> +#define WACOM_QUERY_REPORT 3
> #define WACOM_QUERY_SIZE 19
>
> struct wacom_features {
> @@ -51,22 +58,24 @@ static int wacom_query_device(struct i2c_client *client,
> struct wacom_features *features)
> {
> int ret;
> - u8 cmd1[] = { WACOM_CMD_QUERY0, WACOM_CMD_QUERY1,
> - WACOM_CMD_QUERY2, WACOM_CMD_QUERY3 };
> - u8 cmd2[] = { WACOM_CMD_THROW0, WACOM_CMD_THROW1 };
> u8 data[WACOM_QUERY_SIZE];
> +
> + u8 get_query_data_cmd[] = {
> + WACOM_COMMAND_LSB,
> + WACOM_COMMAND_MSB,
> + REPORT_FEATURE | WACOM_QUERY_REPORT,
> + OPCODE_GET_REPORT,
> + WACOM_DATA_LSB,
> + WACOM_DATA_MSB,
> + };
> +
> struct i2c_msg msgs[] = {
> + // Request reading of feature ReportID: 3 (Pen Query Data)
> {
> .addr = client->addr,
> .flags = 0,
> - .len = sizeof(cmd1),
> - .buf = cmd1,
> - },
> - {
> - .addr = client->addr,
> - .flags = 0,
> - .len = sizeof(cmd2),
> - .buf = cmd2,
> + .len = sizeof(get_query_data_cmd),
> + .buf = get_query_data_cmd,

This combines writes into one message. Is this safe and works for all
devices? At the very least this needs to be mentioned in the patch
description.

> },
> {
> .addr = client->addr,
> --
> 2.31.1
>

Thanks.

--
Dmitry