Re: [PATCH v2 4/7] HID: ft260: support i2c reads greater than HID report size

From: Enrik Berkhan
Date: Tue Oct 04 2022 - 14:11:49 EST


Hi Michael,

On Wed, 2022-09-28 at 17:48 +0300, Michael Zaidman wrote:
> diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c
> index bfda5b191a3a..cb8f1782d1f0 100644
> --- a/drivers/hid/hid-ft260.c
> +++ b/drivers/hid/hid-ft260.c
> @@ -460,49 +460,68 @@ static int ft260_smbus_write(struct ft260_device *dev, u8 addr, u8 cmd,
> static int ft260_i2c_read(struct ft260_device *dev, u8 addr, u8 *data,
> u16 len, u8 flag)
> {
> + u16 rd_len;
> + int timeout, ret;
> struct ft260_i2c_read_request_report rep;
> struct hid_device *hdev = dev->hdev;
> - int timeout;
> - int ret;
> + bool first = true;
>
> - if (len > FT260_RD_DATA_MAX) {
> - hid_err(hdev, "%s: unsupported rd len: %d\n", __func__, len);
> - return -EINVAL;
> - }
> + do {
> + if (first) {
> + if (flag & FT260_FLAG_START_REPEATED)

I think the test should be

if ((flag & FT260_FLAG_START_REPEATED) == FT260_FLAG_START_REPEATED)

Otherwise, flag will never be FT260_FLAG_START ( = 2), as
FT260_FLAG_START_REPEATED (= 3) has tow bits set. It looks as if bit 0
actually means "repeated", bit 1 is "start" and bit 2 is "stop".

Cheers,
Enrik