Re: [PATCH v2 2/2] Input: add Apple SPI keyboard and trackpad driver.

Andy Shevchenko
2019-02-26T09:21:06Z

On Thu, Feb 21, 2019 at 02:56:09AM -0800, Ronald Tschalär wrote:
> The keyboard and trackpad on recent MacBook's (since 8,1) and
> MacBookPro's (13,* and 14,*) are attached to an SPI controller instead
> of USB, as previously. The higher level protocol is not publicly
> documented and hence has been reverse engineered. As a consequence there
> are still a number of unknown fields and commands. However, the known
> parts have been working well and received extensive testing and use.
>
> In order for this driver to work, the proper SPI drivers need to be
> loaded too; for MB8,1 these are spi_pxa2xx_platform and spi_pxa2xx_pci;
> for all others they are spi_pxa2xx_platform and intel_lpss_pci. For this
> reason enabling this driver in the config implies enabling the above
> drivers.

> +config KEYBOARD_APPLESPI
> + tristate "Apple SPI keyboard and trackpad"

> + depends on ACPI && SPI && EFI

I would rather want to see separate line for SPI...

> + depends on X86 || COMPILE_TEST

...like here

depends on SPI

> + imply SPI_PXA2XX
> + imply SPI_PXA2XX_PCI
> + imply MFD_INTEL_LPSS_PCI
> + help
> + Say Y here if you are running Linux on any Apple MacBook8,1 or later,
> + or any MacBookPro13,* or MacBookPro14,*.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called applespi.

/* Perhaps a comment here that this mimics struct drm_rect */

> +struct applespi_tp_info {
> + int x_min;
> + int y_min;
> + int x_max;
> + int y_max;
> +};

...see above

> +static inline bool applespi_check_write_status(struct applespi_data *applespi,
> + int sts)
> +{
> + static u8 status_ok[] = { 0xac, 0x27, 0x68, 0xd5 };
> +
> + if (sts < 0) {
> + dev_warn(DEV(applespi), "Error writing to device: %d\n", sts);
> + return false;
> + }
> +
> + if (memcmp(applespi->tx_status, status_ok, APPLESPI_STATUS_SIZE)) {

> + dev_warn(DEV(applespi), "Error writing to device: %*ph\n",

Hmm... DEV() is too generic name for custom macro. And frankly I don't think
it's good to have in the first place.

> + APPLESPI_STATUS_SIZE, applespi->tx_status);
> + return false;
> + }
> +
> + return true;
> +}

> +static void applespi_set_bl_level(struct led_classdev *led_cdev,
> + enum led_brightness value)
> +{
> + struct applespi_data *applespi =
> + container_of(led_cdev, struct applespi_data, backlight_info);
> + unsigned long flags;
> + int sts;
> +
> + spin_lock_irqsave(&applespi->cmd_msg_lock, flags);
> +

> + if (value == 0)
> + applespi->want_bl_level = value;
> + else
> + /*
> + * The backlight does not turn on till level 32, so we scale
> + * the range here so that from a user's perspective it turns
> + * on at 1.
> + */
> + applespi->want_bl_level =
> + ((value * KBD_BL_LEVEL_ADJ) / KBD_BL_LEVEL_SCALE +
> + KBD_BL_LEVEL_MIN);

Fir multi-line conditionals the style is
if () {
} else {
}

> +
> + sts = applespi_send_cmd_msg(applespi);
> +
> + spin_unlock_irqrestore(&applespi->cmd_msg_lock, flags);
> +}

> +static void
> +applespi_remap_fn_key(struct keyboard_protocol *keyboard_protocol)
> +{
> + unsigned char tmp;

> + unsigned long *modifiers =
> + (unsigned long *)&keyboard_protocol->modifiers;

I would leave it on one online despite checkpatch warning (also, instead of
(unsigned long *) the (void *) might be used as a small trick).

> +
> + if (!fnremap || fnremap > ARRAY_SIZE(applespi_controlcodes) ||
> + !applespi_controlcodes[fnremap - 1])
> + return;
> +
> + tmp = keyboard_protocol->fn_pressed;
> + keyboard_protocol->fn_pressed = test_bit(fnremap - 1, modifiers);
> + if (tmp)

> + __set_bit(fnremap - 1, modifiers);
> + else
> + __clear_bit(fnremap - 1, modifiers);

Oh, this is not good. modifiers should be really unsigned long bounary,
otherwise it is potential overflow.

Best to fix is to define them as unsigned long in the first place.

> +}

> + applespi->last_keys_fn_pressed[i]);
> + input_report_key(applespi->keyboard_input_dev, key, 0);
> + applespi->last_keys_fn_pressed[i] = 0;
> + }

> + for (i = 0; i < MAX_MODIFIERS; i++) {

> + u8 *modifiers = &keyboard_protocol->modifiers;
> +
> + if (test_bit(i, (unsigned long *)modifiers))

Oh, this is not good idea, see above.

> + if (touchpad_dimensions[0]) {
> + int x, y, w, h;
> +

> + if (sscanf(touchpad_dimensions, "%dx%d+%u+%u", &x, &y, &w, &h)
> + == 4) {

I would leave this on one line. Or use temporary variable

int ret;

ret = sscanf();
if (ret ...) {

> + dev_info(DEV(applespi),
> + "Overriding touchpad dimensions from module param\n");
> + applespi->tp_info.x_min = x;
> + applespi->tp_info.y_min = y;
> + applespi->tp_info.x_max = x + w;
> + applespi->tp_info.y_max = y + h;
> + } else {
> + dev_warn(DEV(applespi),
> + "Invalid touchpad dimensions '%s': must be in the form XxY+W+H\n",
> + touchpad_dimensions);
> + touchpad_dimensions[0] = '\0';
> + }
> + }

--
With Best Regards,
Andy Shevchenko