Re: [PATCH 5/7] Support new Alps device that name is T4

From: Jiri Kosina
Date: Fri Sep 15 2017 - 20:34:44 EST


On Tue, 12 Sep 2017, Masaki Ota wrote:

> From: Masaki Ota <masaki.ota@xxxxxxxxxxx>
> -Add T4 device code and Product ID
> -This device is used on HP EliteBook 1000 series and Zbook Stduio
[ ... snip ... ]
> Signed-off-by: Masaki Ota <masaki.ota@xxxxxxxxxxx>
> +static int t4_read_write_register(struct hid_device *hdev, u32 address,
> + u8 *read_val, u8 write_val, bool read_flag)
> +{
> + int ret;
> + u16 check_sum;
> + u8 *input;
> + u8 *readbuf;
> +
> + input = kzalloc(T4_FEATURE_REPORT_LEN, GFP_KERNEL);
> + if (!input)
> + return -ENOMEM;
> +
> + input[0] = T4_FEATURE_REPORT_ID;
> + if (read_flag) {
> + input[1] = T4_CMD_REGISTER_READ;
> + input[8] = 0x00;
> + } else {
> + input[1] = T4_CMD_REGISTER_WRITE;
> + input[8] = write_val;
> + }
> + put_unaligned_le32(address, input + 2);
> + input[6] = 1;
> + input[7] = 0;
> +
> + /* Calculate the checksum */
> + check_sum = t4_calc_check_sum(input, 1, 8);
> + input[9] = (u8)check_sum;
> + input[10] = (u8)(check_sum >> 8);
> + input[11] = 0;
> +
> + ret = hid_hw_raw_request(hdev, T4_FEATURE_REPORT_ID, input,
> + T4_FEATURE_REPORT_LEN,
> + HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
> +
> + if (ret < 0) {
> + dev_err(&hdev->dev, "failed to read command (%d)\n", ret);
> + goto exit;
> + }
> +
> + if (read_flag) {
> + readbuf = kzalloc(T4_FEATURE_REPORT_LEN, GFP_KERNEL);
> + if (!readbuf) {
> + ret = -ENOMEM;
> + goto exit;
> + }
> +
> + ret = hid_hw_raw_request(hdev, T4_FEATURE_REPORT_ID, readbuf,
> + T4_FEATURE_REPORT_LEN,
> + HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
> + if (ret < 0) {
> + dev_err(&hdev->dev, "failed read register (%d)\n", ret);
> + kfree(readbuf);
> + goto exit;
> + }
> +
> + if (*(u32 *)&readbuf[6] != address) {
> + dev_err(&hdev->dev, "read register address error (%x,%x)\n",
> + *(u32 *)&readbuf[6], address);
> + kfree(readbuf);
> + goto exit;
> + }
> +
> + if (*(u16 *)&readbuf[10] != 1) {
> + dev_err(&hdev->dev, "read register size error (%x)\n",
> + *(u16 *)&readbuf[10]);
> + kfree(readbuf);
> + goto exit;
> + }
> +
> + check_sum = t4_calc_check_sum(readbuf, 6, 7);
> + if (*(u16 *)&readbuf[13] != check_sum) {
> + dev_err(&hdev->dev, "read register checksum error (%x,%x)\n",
> + *(u16 *)&readbuf[13], check_sum);
> + kfree(readbuf);
> + goto exit;
> + }
> +
> + *read_val = readbuf[12];
> +
> + kfree(readbuf);

You have a lot of

kfree(readbuf);
goto exit;

duplicates here, and you're freeing the buffer before returning anyway in
all cases, so it'd make sense to introduce another label (say
exit_readbuf) before the exit one, and free it there in a common exit
path.

[ ... snip ... ]
> +static int t4_raw_event(struct alps_dev *hdata, u8 *data, int size)
> +{
> + unsigned int x, y, z;
> + int i;
> + struct t4_input_report *p_report = (struct t4_input_report *)data;
> +
> + if (!data)
> + return 0;
> + for (i = 0; i < hdata->max_fingers; i++) {
> + x = p_report->contact[i].x_hi << 8 | p_report->contact[i].x_lo;
> + y = p_report->contact[i].y_hi << 8 | p_report->contact[i].y_lo;
> + y = hdata->y_max - y + hdata->y_min;
> + z = (p_report->contact[i].palm < 0x80 &&
> + p_report->contact[i].palm > 0) * 62;
> + if (x == 0xffff) {
> + x = 0;
> + y = 0;
> + z = 0;
> + }
> + input_mt_slot(hdata->input, i);
> +
> + input_mt_report_slot_state(hdata->input,
> + MT_TOOL_FINGER, z != 0);
> +
> + if (!z)
> + continue;
> +
> + input_report_abs(hdata->input, ABS_MT_POSITION_X, x);
> + input_report_abs(hdata->input, ABS_MT_POSITION_Y, y);
> + input_report_abs(hdata->input, ABS_MT_PRESSURE, z);
> + }
> + input_mt_sync_frame(hdata->input);
> +
> + input_report_key(hdata->input, BTN_LEFT, p_report->button);

Extra tab here?

> -static int alps_post_resume(struct hid_device *hdev)
> +static int __maybe_unused alps_post_reset(struct hid_device *hdev)

Do we really need the __maybe_unused annotation here? Why not just hide
the whole post-reset callback handling into a #ifdef CONFIG_PM block?

Thanks,

--
Jiri Kosina
SUSE Labs