Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

From: Darren Hart
Date: Wed Nov 19 2014 - 14:20:02 EST


On Fri, Nov 14, 2014 at 01:23:33PM +0100, Pali Rohár wrote:
> This patch adds support for configuring keyboard backlight settings on supported
> Dell laptops. It exports kernel leds interface and uses Dell SMBIOS tokens or
> keyboard class interface.
>
> With this patch it is possible to set:
> * keyboard backlight level
> * timeout after which will be backlight automatically turned off
> * input activity triggers (keyboard, touchpad, mouse) which enable backlight
> * ambient light settings
>
> Settings are exported via sysfs:
> /sys/class/leds/dell::kbd_backlight/
>
> Code is based on newly released documentation by Dell in libsmbios project.
>
> Signed-off-by: Pali Rohár <pali.rohar@xxxxxxxxx>
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt@xxxxxxxxx>

Hi Pali,

Apologies for the delay.

I'm somewhat concerned that this patch doubles the size of this driver. When
we're adding this much code, I have to ask - does it make sense to grow this
driver rather than create a new one?

There is no ACPI backlight driver on these systems? We need a platform driver?

Matthew, I'd appreciate your thoughts as you're listed as the module author.

My main commentary throughout is surrounding large indented logic blocks which
could be less nested by checking for errors and returning/jumping rather than
using an if (success) block for the main logic. There are various places where
some logic reduction would result in some significantly tighter code.

Specific comments below.

> ---
> drivers/platform/x86/dell-laptop.c | 1001 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 997 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
> index 233d2ee..bf5b1cc 100644
> --- a/drivers/platform/x86/dell-laptop.c
> +++ b/drivers/platform/x86/dell-laptop.c
> @@ -2,9 +2,11 @@
> * Driver for Dell laptop extras
> *
> * Copyright (c) Red Hat <mjg@xxxxxxxxxx>
> + * Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@xxxxxxxxx>
> + * Copyright (c) 2014 Pali Rohár <pali.rohar@xxxxxxxxx>
> *
> - * Based on documentation in the libsmbios package, Copyright (C) 2005 Dell
> - * Inc.
> + * Based on documentation in the libsmbios package:
> + * Copyright (C) 2005-2014 Dell Inc.
> *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License version 2 as
> @@ -32,6 +34,13 @@
> #include "../../firmware/dcdbas.h"
>
> #define BRIGHTNESS_TOKEN 0x7d
> +#define KBD_LED_OFF_TOKEN 0x01E1
> +#define KBD_LED_ON_TOKEN 0x01E2
> +#define KBD_LED_AUTO_TOKEN 0x01E3
> +#define KBD_LED_AUTO_25_TOKEN 0x02EA
> +#define KBD_LED_AUTO_50_TOKEN 0x02EB
> +#define KBD_LED_AUTO_75_TOKEN 0x02EC
> +#define KBD_LED_AUTO_100_TOKEN 0x02F6
>
> /* This structure will be modified by the firmware when we enter
> * system management mode, hence the volatiles */
> @@ -62,6 +71,10 @@ struct calling_interface_structure {
>
> struct quirk_entry {
> u8 touchpad_led;
> +
> + /* Ordered list of timeouts expressed in seconds.
> + * The list must end with -1 */
> + int kbd_timeouts[];
> };
>
> static struct quirk_entry *quirks;
> @@ -76,6 +89,10 @@ static int __init dmi_matched(const struct dmi_system_id *dmi)
> return 1;
> }
>
> +static struct quirk_entry quirk_dell_xps13_9333 = {
> + .kbd_timeouts = { 0, 5, 15, 60, 5*60, 15*60, -1 },
> +};
> +
> static int da_command_address;
> static int da_command_code;
> static int da_num_tokens;
> @@ -268,6 +285,15 @@ static const struct dmi_system_id dell_quirks[] __initconst = {
> },
> .driver_data = &quirk_dell_vostro_v130,
> },
> + {
> + .callback = dmi_matched,
> + .ident = "Dell XPS13 9333",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> + DMI_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
> + },
> + .driver_data = &quirk_dell_xps13_9333,
> + },
> { }
> };
>
> @@ -332,17 +358,29 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
> }
> }
>
> -static int find_token_location(int tokenid)
> +static int find_token_id(int tokenid)
> {
> int i;
> +
> for (i = 0; i < da_num_tokens; i++) {
> if (da_tokens[i].tokenID == tokenid)
> - return da_tokens[i].location;
> + return i;
> }
>
> return -1;
> }
>
> +static int find_token_location(int tokenid)
> +{
> + int id;
> +
> + id = find_token_id(tokenid);
> + if (id == -1)
> + return -1;
> +
> + return da_tokens[id].location;
> +}
> +
> static struct calling_interface_buffer *
> dell_send_request(struct calling_interface_buffer *buffer, int class,
> int select)
> @@ -790,6 +828,956 @@ static void touchpad_led_exit(void)
> led_classdev_unregister(&touchpad_led);
> }
>
> +/* Derived from information in smbios-keyboard-ctl:
> +
> + cbClass 4
> + cbSelect 11
> + Keyboar illumination
> + cbArg1 determines the function to be performed
> +
> + cbArg1 0x0 = Get Feature Information
> + cbRES1 Standard return codes (0, -1, -2)
> + cbRES2, word0 Bitmap of user-selectable modes
> + bit 0 Always off (All systems)
> + bit 1 Always on (Travis ATG, Siberia)
> + bit 2 Auto: ALS-based On; ALS-based Off (Travis ATG)
> + bit 3 Auto: ALS- and input-activity-based On; input-activity based Off
> + bit 4 Auto: Input-activity-based On; input-activity based Off
> + bit 5 Auto: Input-activity-based On (illumination level 25%); input-activity based Off
> + bit 6 Auto: Input-activity-based On (illumination level 50%); input-activity based Off
> + bit 7 Auto: Input-activity-based On (illumination level 75%); input-activity based Off
> + bit 8 Auto: Input-activity-based On (illumination level 100%); input-activity based Off
> + bits 9-15 Reserved for future use
> + cbRES2, byte2 Reserved for future use
> + cbRES2, byte3 Keyboard illumination type
> + 0 Reserved
> + 1 Tasklight
> + 2 Backlight
> + 3-255 Reserved for future use
> + cbRES3, byte0 Supported auto keyboard illumination trigger bitmap.
> + bit 0 Any keystroke
> + bit 1 Touchpad activity
> + bit 2 Pointing stick
> + bit 3 Any mouse
> + bits 4-7 Reserved for future use
> + cbRES3, byte1 Supported timeout unit bitmap
> + bit 0 Seconds
> + bit 1 Minutes
> + bit 2 Hours
> + bit 3 Days
> + bits 4-7 Reserved for future use
> + cbRES3, byte2 Number of keyboard light brightness levels
> + cbRES4, byte0 Maximum acceptable seconds value (0 if seconds not supported).
> + cbRES4, byte1 Maximum acceptable minutes value (0 if minutes not supported).
> + cbRES4, byte2 Maximum acceptable hours value (0 if hours not supported).
> + cbRES4, byte3 Maximum acceptable days value (0 if days not supported)
> +
> + cbArg1 0x1 = Get Current State
> + cbRES1 Standard return codes (0, -1, -2)
> + cbRES2, word0 Bitmap of current mode state
> + bit 0 Always off (All systems)
> + bit 1 Always on (Travis ATG, Siberia)
> + bit 2 Auto: ALS-based On; ALS-based Off (Travis ATG)
> + bit 3 Auto: ALS- and input-activity-based On; input-activity based Off
> + bit 4 Auto: Input-activity-based On; input-activity based Off
> + bit 5 Auto: Input-activity-based On (illumination level 25%); input-activity based Off
> + bit 6 Auto: Input-activity-based On (illumination level 50%); input-activity based Off
> + bit 7 Auto: Input-activity-based On (illumination level 75%); input-activity based Off
> + bit 8 Auto: Input-activity-based On (illumination level 100%); input-activity based Off
> + bits 9-15 Reserved for future use
> + Note: Only One bit can be set
> + cbRES2, byte2 Currently active auto keyboard illumination triggers.
> + bit 0 Any keystroke
> + bit 1 Touchpad activity
> + bit 2 Pointing stick
> + bit 3 Any mouse
> + bits 4-7 Reserved for future use
> + cbRES2, byte3 Current Timeout
> + bits 7:6 Timeout units indicator:
> + 00b Seconds
> + 01b Minutes
> + 10b Hours
> + 11b Days
> + bits 5:0 Timeout value (0-63) in sec/min/hr/day
> + NOTE: A value of 0 means always on (no timeout) if any bits of RES3 byte
> + are set upon return from the [Get feature information] call.
> + cbRES3, byte0 Current setting of ALS value that turns the light on or off.
> + cbRES3, byte1 Current ALS reading
> + cbRES3, byte2 Current keyboard light level.
> +
> + cbArg1 0x2 = Set New State
> + cbRES1 Standard return codes (0, -1, -2)
> + cbArg2, word0 Bitmap of current mode state
> + bit 0 Always off (All systems)
> + bit 1 Always on (Travis ATG, Siberia)
> + bit 2 Auto: ALS-based On; ALS-based Off (Travis ATG)
> + bit 3 Auto: ALS- and input-activity-based On; input-activity based Off
> + bit 4 Auto: Input-activity-based On; input-activity based Off
> + bit 5 Auto: Input-activity-based On (illumination level 25%); input-activity based Off
> + bit 6 Auto: Input-activity-based On (illumination level 50%); input-activity based Off
> + bit 7 Auto: Input-activity-based On (illumination level 75%); input-activity based Off
> + bit 8 Auto: Input-activity-based On (illumination level 100%); input-activity based Off
> + bits 9-15 Reserved for future use
> + Note: Only One bit can be set
> + cbArg2, byte2 Desired auto keyboard illumination triggers. Must remain inactive to allow
> + keyboard to turn off automatically.
> + bit 0 Any keystroke
> + bit 1 Touchpad activity
> + bit 2 Pointing stick
> + bit 3 Any mouse
> + bits 4-7 Reserved for future use
> + cbArg2, byte3 Desired Timeout
> + bits 7:6 Timeout units indicator:
> + 00b Seconds
> + 01b Minutes
> + 10b Hours
> + 11b Days
> + bits 5:0 Timeout value (0-63) in sec/min/hr/day
> + cbArg3, byte0 Desired setting of ALS value that turns the light on or off.
> + cbArg3, byte2 Desired keyboard light level.
> +*/
> +
> +
> +enum kbd_timeout_unit {
> + KBD_TIMEOUT_SECONDS = 0,
> + KBD_TIMEOUT_MINUTES,
> + KBD_TIMEOUT_HOURS,
> + KBD_TIMEOUT_DAYS,
> +};
> +
> +enum kbd_mode_bit {
> + KBD_MODE_BIT_OFF = 0,
> + KBD_MODE_BIT_ON,
> + KBD_MODE_BIT_ALS,
> + KBD_MODE_BIT_TRIGGER_ALS,
> + KBD_MODE_BIT_TRIGGER,
> + KBD_MODE_BIT_TRIGGER_25,
> + KBD_MODE_BIT_TRIGGER_50,
> + KBD_MODE_BIT_TRIGGER_75,
> + KBD_MODE_BIT_TRIGGER_100,
> +};
> +
> +#define kbd_is_als_mode_bit(bit) \
> + ((bit) == KBD_MODE_BIT_ALS || (bit) == KBD_MODE_BIT_TRIGGER_ALS)
> +#define kbd_is_trigger_mode_bit(bit) \
> + ((bit) >= KBD_MODE_BIT_TRIGGER_ALS && (bit) <= KBD_MODE_BIT_TRIGGER_100)
> +#define kbd_is_level_mode_bit(bit) \
> + ((bit) >= KBD_MODE_BIT_TRIGGER_25 && (bit) <= KBD_MODE_BIT_TRIGGER_100)
> +
> +struct kbd_info {
> + u16 modes;
> + u8 type;
> + u8 triggers;
> + u8 levels;
> + u8 seconds;
> + u8 minutes;
> + u8 hours;
> + u8 days;
> +};
> +
> +struct kbd_state {
> + u8 mode_bit;
> + u8 triggers;
> + u8 timeout_value;
> + u8 timeout_unit;
> + u8 als_setting;
> + u8 als_value;
> + u8 level;
> +};
> +
> +static const int kbd_tokens[] = {
> + KBD_LED_OFF_TOKEN,
> + KBD_LED_AUTO_25_TOKEN,
> + KBD_LED_AUTO_50_TOKEN,
> + KBD_LED_AUTO_75_TOKEN,
> + KBD_LED_AUTO_100_TOKEN,
> + KBD_LED_ON_TOKEN,
> +};
> +
> +static u16 kbd_token_bits;
> +
> +static struct kbd_info kbd_info;
> +static bool kbd_als_supported;
> +static bool kbd_triggers_supported;
> +
> +static u8 kbd_mode_levels[16];
> +static int kbd_mode_levels_count;
> +
> +static u8 kbd_previous_level;
> +static u8 kbd_previous_mode_bit;
> +
> +static bool kbd_led_present;
> +
> +static int kbd_get_info(struct kbd_info *info)
> +{
> + u8 units;
> + int ret;
> +
> + get_buffer();
> +
> + buffer->input[0] = 0x0;
> + dell_send_request(buffer, 4, 11);
> + ret = buffer->output[0];
> +
> + if (ret == 0) {

Generally speaking, check for error to keep the main logic from getting
indented.

if (buffer->output[0]) {
ret = -EINVAL;
goto out;
}

> + info->modes = buffer->output[1] & 0xFFFF;
> + info->type = (buffer->output[1] >> 24) & 0xFF;
> + info->triggers = buffer->output[2] & 0xFF;
> + units = (buffer->output[2] >> 8) & 0xFF;
> + info->levels = (buffer->output[2] >> 16) & 0xFF;
> + if (units & BIT(0))
> + info->seconds = (buffer->output[3] >> 0) & 0xFF;
> + if (units & BIT(1))
> + info->minutes = (buffer->output[3] >> 8) & 0xFF;
> + if (units & BIT(2))
> + info->hours = (buffer->output[3] >> 16) & 0xFF;
> + if (units & BIT(3))
> + info->days = (buffer->output[3] >> 24) & 0xFF;
> + }
> +

out:

> + release_buffer();
> +
> + if (ret)
> + return -EINVAL;

Drop this.

> + return 0;

return ret;

In this particular case, it might be shorter by a line or two to drop the ret
variable and simply release_buffer() and return -EINVAL in the error check above
and just return 0 here.

> +}
> +
> +static unsigned int kbd_get_max_level(void)
> +{
> + if (kbd_info.levels != 0)
> + return kbd_info.levels;

This test.... does nothing? if it is 0, you still return 0 below :-)

> + if (kbd_mode_levels_count > 0)
> + return kbd_mode_levels_count - 1;
> + return 0;

So the function is:

return kbd_mode_levels_count > 0 ? kbd_mode_levels_count - 1 : kbd_info.levels;

The if blocks are more legible, so that's fine, but the first one doesn't seem
to do anything and you can replace the final return with return kbd_info.levels.

> +}
> +
> +static int kbd_get_level(struct kbd_state *state)
> +{
> + int i;
> +
> + if (kbd_info.levels != 0)
> + return state->level;
> +
> + if (kbd_mode_levels_count > 0) {

The if test is redundant, the for loop will simply run 0 iterations in this
case.

> + for (i = 0; i < kbd_mode_levels_count; ++i)
> + if (kbd_mode_levels[i] == state->mode_bit)
> + return i;
> + return 0;
> + }
> +
> + return -EINVAL;

Ah, so you're testing for an invalid kbd_mode_levels_count? Is that possible?
Should that perhaps be an unsigned integer, then we only have to worry about 0.
Can we test for that at driver init? How do we get to here with a bad
kbd_mode_levels_count?

> +}
> +
> +static int kbd_set_level(struct kbd_state *state, u8 level)
> +{
> + if (kbd_info.levels != 0) {

Again, generally speaking, test for errors and indent those, rather than the
core logic.

> + if (level != 0)
> + kbd_previous_level = level;
> + if (state->level == level)
> + return 0;
> + state->level = level;
> + if (level != 0 && state->mode_bit == KBD_MODE_BIT_OFF)
> + state->mode_bit = kbd_previous_mode_bit;
> + else if (level == 0 && state->mode_bit != KBD_MODE_BIT_OFF) {
> + kbd_previous_mode_bit = state->mode_bit;
> + state->mode_bit = KBD_MODE_BIT_OFF;
> + }
> + return 0;
> + }
> +
> + if (kbd_mode_levels_count > 0 && level < kbd_mode_levels_count) {
> + if (level != 0)
> + kbd_previous_level = level;
> + state->mode_bit = kbd_mode_levels[level];
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int kbd_get_state(struct kbd_state *state)
> +{
> + int ret;
> +
> + get_buffer();
> +
> + buffer->input[0] = 0x1;
> + dell_send_request(buffer, 4, 11);
> + ret = buffer->output[0];
> +
> + if (ret == 0) {
> + state->mode_bit = ffs(buffer->output[1] & 0xFFFF);
> + if (state->mode_bit != 0)
> + state->mode_bit--;
> + state->triggers = (buffer->output[1] >> 16) & 0xFF;
> + state->timeout_value = (buffer->output[1] >> 24) & 0x3F;
> + state->timeout_unit = (buffer->output[1] >> 30) & 0x3;
> + state->als_setting = buffer->output[2] & 0xFF;
> + state->als_value = (buffer->output[2] >> 8) & 0xFF;
> + state->level = (buffer->output[2] >> 16) & 0xFF;
> + }
> +
> + release_buffer();
> +
> + if (ret)
> + return -EINVAL;
> +
> + return 0;

Same comment about error checking approach and indentation.

> +}
> +
> +static int kbd_set_state(struct kbd_state *state)
> +{
> + int ret;
> +
> + get_buffer();
> + buffer->input[0] = 0x2;
> + buffer->input[1] = BIT(state->mode_bit) & 0xFFFF;
> + buffer->input[1] |= (state->triggers & 0xFF) << 16;
> + buffer->input[1] |= (state->timeout_value & 0x3F) << 24;
> + buffer->input[1] |= (state->timeout_unit & 0x3) << 30;
> + buffer->input[2] = state->als_setting & 0xFF;
> + buffer->input[2] |= (state->level & 0xFF) << 16;
> + dell_send_request(buffer, 4, 11);
> + ret = buffer->output[0];
> + release_buffer();
> +
> + if (ret)
> + return -EINVAL;

Also, is EINVAL right here and elsewhere? Or did something fail? EXIO?

> +
> + return 0;
> +}
> +
> +static int kbd_set_state_safe(struct kbd_state *state, struct kbd_state *old)
> +{
> + int ret;
> +
> + ret = kbd_set_state(state);
> + if (ret == 0)
> + return 0;
> +
> + if (kbd_set_state(old))
> + pr_err("Setting old previous keyboard state failed\n");

And if we got an error and kbd_set_state(old) doesn't return !0, what's the
state of things? Still a failure a presume?

> +
> + return ret;
> +}
> +
> +static int kbd_set_token_bit(u8 bit)
> +{
> + int id;
> + int ret;
> +
> + if (bit >= ARRAY_SIZE(kbd_tokens))
> + return -EINVAL;
> +
> + id = find_token_id(kbd_tokens[bit]);
> + if (id == -1)
> + return -EINVAL;
> +
> + get_buffer();
> + buffer->input[0] = da_tokens[id].location;
> + buffer->input[1] = da_tokens[id].value;
> + dell_send_request(buffer, 1, 0);
> + ret = buffer->output[0];
> + release_buffer();
> +
> + if (ret)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int kbd_get_token_bit(u8 bit)
> +{
> + int id;
> + int ret;
> + int val;
> +
> + if (bit >= ARRAY_SIZE(kbd_tokens))
> + return -EINVAL;
> +
> + id = find_token_id(kbd_tokens[bit]);
> + if (id == -1)
> + return -EINVAL;
> +
> + get_buffer();
> + buffer->input[0] = da_tokens[id].location;
> + dell_send_request(buffer, 0, 0);
> + ret = buffer->output[0];
> + val = buffer->output[1];
> + release_buffer();
> +
> + if (ret)
> + return -EINVAL;
> +
> + return (val == da_tokens[id].value);
> +}
> +
> +static int kbd_get_first_active_token_bit(void)
> +{
> + int i;
> + int ret;
> +
> + for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i) {
> + ret = kbd_get_token_bit(i);
> + if (ret == 1)
> + return i;
> + }
> +
> + return ret;
> +}
> +
> +static int kbd_get_valid_token_counts(void)
> +{
> + return hweight16(kbd_token_bits);
> +}
> +
> +static void kbd_init(void)
> +{
> + struct kbd_state state;
> + int ret;
> + int i;
> +
> + ret = kbd_get_info(&kbd_info);
> +
> + if (ret == 0) {
> +

Checking for success, let's invert and avoid the indentation here too.

> + kbd_get_state(&state);
> +
> + /* NOTE: timeout value is stored in 6 bits so max value is 63 */
> + if (kbd_info.seconds > 63)
> + kbd_info.seconds = 63;
> + if (kbd_info.minutes > 63)
> + kbd_info.minutes = 63;
> + if (kbd_info.hours > 63)
> + kbd_info.hours = 63;
> + if (kbd_info.days > 63)
> + kbd_info.days = 63;
> +
> + /* NOTE: On tested machines ON mode did not work and caused
> + * problems (turned backlight off) so do not use it
> + */
> + kbd_info.modes &= ~BIT(KBD_MODE_BIT_ON);
> +
> + kbd_previous_level = kbd_get_level(&state);
> + kbd_previous_mode_bit = state.mode_bit;
> +
> + if (kbd_previous_level == 0) {
> + if (kbd_get_max_level() != 0)
> + kbd_previous_level = 1;
> + }
> +
> + if (kbd_previous_mode_bit == KBD_MODE_BIT_OFF) {
> + kbd_previous_mode_bit =
> + ffs(kbd_info.modes & ~BIT(KBD_MODE_BIT_OFF));
> + if (kbd_previous_mode_bit != 0)
> + kbd_previous_mode_bit--;
> + }
> +
> + if (kbd_info.modes & (BIT(KBD_MODE_BIT_ALS) |
> + BIT(KBD_MODE_BIT_TRIGGER_ALS)))
> + kbd_als_supported = true;
> +
> + if (kbd_info.modes & (
> + BIT(KBD_MODE_BIT_TRIGGER_ALS) | BIT(KBD_MODE_BIT_TRIGGER) |
> + BIT(KBD_MODE_BIT_TRIGGER_25) | BIT(KBD_MODE_BIT_TRIGGER_50) |
> + BIT(KBD_MODE_BIT_TRIGGER_75) | BIT(KBD_MODE_BIT_TRIGGER_100)
> + ))
> + kbd_triggers_supported = true;
> +
> + for (i = 0; i < 16; ++i)
> + if (kbd_is_level_mode_bit(i) &&
> + (BIT(i) & kbd_info.modes))
> + kbd_mode_levels[1+kbd_mode_levels_count++] = i;
> +
> + if (kbd_mode_levels_count > 0) {
> + for (i = 0; i < 16; ++i) {
> + if (BIT(i) & kbd_info.modes) {
> + kbd_mode_levels[0] = i;
> + break;
> + }
> + }
> + kbd_mode_levels_count++;
> + }
> +
> + }
> +
> + for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i)
> + if (find_token_id(kbd_tokens[i]) != -1)
> + kbd_token_bits |= BIT(i);
> +
> + if (kbd_token_bits != 0 || ret == 0)
> + kbd_led_present = true;
> +}
> +
> +static ssize_t kbd_led_timeout_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct kbd_state state;
> + struct kbd_state new_state;
> + int ret;
> + bool convert;
> + char ch;
> + u8 unit;
> + int value;
> + int i;

Decreasing line lenth please.

> +
> + ret = sscanf(buf, "%d %c", &value, &ch);
> + if (ret < 1)
> + return -EINVAL;
> + else if (ret == 1)
> + ch = 's';
> +
> + if (value < 0)
> + return -EINVAL;
> +
> + convert = false;
> +
> + switch (ch) {
> + case 's':
> + if (value > kbd_info.seconds)
> + convert = true;
> + unit = KBD_TIMEOUT_SECONDS;
> + break;
> + case 'm':
> + if (value > kbd_info.minutes)
> + convert = true;
> + unit = KBD_TIMEOUT_MINUTES;
> + break;
> + case 'h':
> + if (value > kbd_info.hours)
> + convert = true;
> + unit = KBD_TIMEOUT_HOURS;
> + break;
> + case 'd':
> + if (value > kbd_info.days)
> + convert = true;
> + unit = KBD_TIMEOUT_DAYS;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + if (quirks && quirks->kbd_timeouts)
> + convert = true;
> +
> + if (convert) {
> + /* NOTE: this switch fall down */

"fall down" ? As in, it intentionally doesn't have breaks?

> + switch (unit) {
> + case KBD_TIMEOUT_DAYS:
> + value *= 24;
> + case KBD_TIMEOUT_HOURS:
> + value *= 60;
> + case KBD_TIMEOUT_MINUTES:
> + value *= 60;
> + unit = KBD_TIMEOUT_SECONDS;
> + }
> +
> + if (quirks && quirks->kbd_timeouts) {
> + for (i = 0; quirks->kbd_timeouts[i] != -1; i++) {
> + if (value <= quirks->kbd_timeouts[i]) {
> + value = quirks->kbd_timeouts[i];
> + break;
> + }
> + }
> + }
> +
> + if (value <= kbd_info.seconds && kbd_info.seconds) {
> + unit = KBD_TIMEOUT_SECONDS;
> + } else if (value/60 <= kbd_info.minutes && kbd_info.minutes) {

One space around operators like / and * please, applies throughout.

> + value /= 60;
> + unit = KBD_TIMEOUT_MINUTES;
> + } else if (value/(60*60) <= kbd_info.hours && kbd_info.hours) {
> + value /= (60*60);
> + unit = KBD_TIMEOUT_HOURS;
> + } else if (value/(60*60*24) <= kbd_info.days && kbd_info.days) {
> + value /= (60*60*24);
> + unit = KBD_TIMEOUT_DAYS;
> + } else {
> + return -EINVAL;
> + }
> + }
> +
> + ret = kbd_get_state(&state);
> + if (ret)
> + return ret;
> +
> + new_state = state;
> + new_state.timeout_value = value;
> + new_state.timeout_unit = unit;
> +
> + ret = kbd_set_state_safe(&new_state, &state);
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +
> +static ssize_t kbd_led_timeout_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct kbd_state state;
> + int ret;
> + int len;
> +
> + ret = kbd_get_state(&state);
> + if (ret)
> + return ret;
> +
> + len = sprintf(buf, "%d", state.timeout_value);
> +
> + switch (state.timeout_unit) {
> + case KBD_TIMEOUT_SECONDS:
> + return len + sprintf(buf+len, "s\n");
> + case KBD_TIMEOUT_MINUTES:
> + return len + sprintf(buf+len, "m\n");
> + case KBD_TIMEOUT_HOURS:
> + return len + sprintf(buf+len, "h\n");
> + case KBD_TIMEOUT_DAYS:
> + return len + sprintf(buf+len, "d\n");
> + default:
> + return -EINVAL;
> + }
> +
> + return len;
> +}
> +
> +static DEVICE_ATTR(stop_timeout, S_IRUGO | S_IWUSR,
> + kbd_led_timeout_show, kbd_led_timeout_store);
> +
> +static const char * const kbd_led_triggers[] = {
> + "keyboard",
> + "touchpad",
> + /*"trackstick"*/ NULL, /* NOTE: trackstick is just alias for touchpad */
> + "mouse",
> +};
> +
> +static ssize_t kbd_led_triggers_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct kbd_state state;
> + struct kbd_state new_state;
> + char trigger[21];
> + bool als_enabled;
> + bool triggers_enabled;
> + bool enable_als;
> + bool disable_als;
> + int trigger_bit;
> + int i;
> + int ret;
> +
> + ret = sscanf(buf, "%20s", trigger);
> + if (ret != 1)
> + return -EINVAL;
> +
> + if (trigger[0] != '+' && trigger[0] != '-')
> + return -EINVAL;
> +
> + ret = kbd_get_state(&state);
> + if (ret)
> + return ret;
> +
> + if (kbd_als_supported)
> + als_enabled = kbd_is_als_mode_bit(state.mode_bit);
> + else
> + als_enabled = false;
> +
> + if (kbd_triggers_supported)
> + triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
> + else
> + triggers_enabled = false;

Could skip the else blocks with initial assignments.

> +
> + enable_als = false;
> + disable_als = false;

Can skip these too.

> +
> + if (kbd_als_supported) {
> + if (strcmp(trigger, "+als") == 0) {
> + if (als_enabled)
> + return count;
> + enable_als = true;
> + } else if (strcmp(trigger, "-als") == 0) {
> + if (!als_enabled)
> + return count;
> + disable_als = true;
> + }
> + }
> +
> + if (enable_als || disable_als) {
> + new_state = state;
> + if (enable_als) {
> + if (triggers_enabled)
> + new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
> + else
> + new_state.mode_bit = KBD_MODE_BIT_ALS;
> + } else {
> + if (triggers_enabled) {
> + new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
> + kbd_set_level(&new_state, kbd_previous_level);
> + } else
> + new_state.mode_bit = KBD_MODE_BIT_ON;

if one block needs braces, use them throughout.
Apply throughout.

> + }
> + if (!(kbd_info.modes & BIT(new_state.mode_bit)))
> + return -EINVAL;
> + ret = kbd_set_state_safe(&new_state, &state);
> + if (ret)
> + return ret;
> + kbd_previous_mode_bit = new_state.mode_bit;
> + return count;
> + }
> +
> + trigger_bit = -1;
> +
> + if (kbd_triggers_supported) {
> + for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
> + if (!(kbd_info.triggers & BIT(i)))
> + continue;
> + if (!kbd_led_triggers[i])
> + continue;
> + if (strcmp(trigger+1, kbd_led_triggers[i]) != 0)
> + continue;
> + if (trigger[0] == '+' &&
> + triggers_enabled && (state.triggers & BIT(i)))
> + return count;
> + if (trigger[0] == '-' &&
> + (!triggers_enabled || !(state.triggers & BIT(i))))
> + return count;
> + trigger_bit = i;
> + break;
> + }
> + }
> +
> + if (trigger_bit != -1) {
> + new_state = state;
> + if (trigger[0] == '+')
> + new_state.triggers |= BIT(trigger_bit);
> + else {
> + new_state.triggers &= ~BIT(trigger_bit);
> + /* NOTE: trackstick bit (2) must be disabled when
> + * disabling touchpad bit (1), otherwise touchpad
> + * bit (1) will not be disabled */
> + if (trigger_bit == 1)
> + new_state.triggers &= ~BIT(2);
> + }
> + if ((kbd_info.triggers & new_state.triggers) !=
> + new_state.triggers)
> + return -EINVAL;
> + if (new_state.triggers && !triggers_enabled) {
> + if (als_enabled)
> + new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
> + else {
> + new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
> + kbd_set_level(&new_state, kbd_previous_level);
> + }
> + } else if (new_state.triggers == 0) {
> + if (als_enabled)
> + new_state.mode_bit = KBD_MODE_BIT_ALS;
> + else
> + kbd_set_level(&new_state, 0);
> + }
> + if (!(kbd_info.modes & BIT(new_state.mode_bit)))
> + return -EINVAL;
> + ret = kbd_set_state_safe(&new_state, &state);
> + if (ret)
> + return ret;
> + if (new_state.mode_bit != KBD_MODE_BIT_OFF)
> + kbd_previous_mode_bit = new_state.mode_bit;
> + return count;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static ssize_t kbd_led_triggers_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct kbd_state state;
> + bool triggers_enabled;
> + int level;
> + int i;
> + int ret;
> + int len;
> +
> + ret = kbd_get_state(&state);
> + if (ret)
> + return ret;
> +
> + len = 0;
> +
> + if (kbd_triggers_supported) {
> + triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
> + level = kbd_get_level(&state);
> + for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
> + if (!(kbd_info.triggers & BIT(i)))
> + continue;
> + if (!kbd_led_triggers[i])
> + continue;
> + if ((triggers_enabled || level <= 0) &&
> + (state.triggers & BIT(i)))
> + buf[len++] = '+';
> + else
> + buf[len++] = '-';
> + len += sprintf(buf+len, "%s ", kbd_led_triggers[i]);
> + }
> + }
> +
> + if (kbd_als_supported) {
> + if (kbd_is_als_mode_bit(state.mode_bit))
> + len += sprintf(buf+len, "+als ");
> + else
> + len += sprintf(buf+len, "-als ");
> + }
> +
> + if (len)
> + buf[len - 1] = '\n';
> +
> + return len;
> +}
> +
> +static DEVICE_ATTR(start_triggers, S_IRUGO | S_IWUSR,
> + kbd_led_triggers_show, kbd_led_triggers_store);
> +
> +static ssize_t kbd_led_als_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct kbd_state state;
> + struct kbd_state new_state;
> + u8 setting;
> + int ret;
> +
> + ret = kstrtou8(buf, 10, &setting);
> + if (ret)
> + return ret;
> +
> + ret = kbd_get_state(&state);
> + if (ret)
> + return ret;
> +
> + new_state = state;
> + new_state.als_setting = setting;
> +
> + ret = kbd_set_state_safe(&new_state, &state);
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +
> +static ssize_t kbd_led_als_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct kbd_state state;
> + int ret;
> +
> + ret = kbd_get_state(&state);
> + if (ret)
> + return ret;
> +
> + return sprintf(buf, "%d\n", state.als_setting);
> +}
> +
> +static DEVICE_ATTR(als_setting, S_IRUGO | S_IWUSR,
> + kbd_led_als_show, kbd_led_als_store);
> +
> +static struct attribute *kbd_led_attrs[] = {
> + &dev_attr_stop_timeout.attr,
> + &dev_attr_start_triggers.attr,
> + &dev_attr_als_setting.attr,
> + NULL,
> +};
> +ATTRIBUTE_GROUPS(kbd_led);
> +
> +static enum led_brightness kbd_led_level_get(struct led_classdev *led_cdev)
> +{
> + int ret;
> + u16 num;
> + struct kbd_state state;
> +
> + if (kbd_get_max_level()) {
> + ret = kbd_get_state(&state);
> + if (ret)
> + return 0;
> + ret = kbd_get_level(&state);
> + if (ret < 0)
> + return 0;
> + return ret;
> + } else if (kbd_get_valid_token_counts()) {
> + ret = kbd_get_first_active_token_bit();
> + if (ret < 0)
> + return 0;
> + for (num = kbd_token_bits; num != 0 && ret > 0; --ret)
> + num &= num - 1; /* clear the first bit set */
> + if (num == 0)
> + return 0;
> + return ffs(num) - 1;
> + } else {
> + pr_warn("Keyboard brightness level control not supported\n");
> + return 0;
> + }

You can drop the else blocks from the above as every case returns explicitly.

if (condA)
return retA;
if (condB)
return retB
return ret

(checkpatch.pl catches this)

> +}
> +
> +static void kbd_led_level_set(struct led_classdev *led_cdev,
> + enum led_brightness value)
> +{
> + struct kbd_state state;
> + struct kbd_state new_state;
> + u16 num;
> +
> + if (kbd_get_max_level()) {
> + if (kbd_get_state(&state))
> + return;
> + new_state = state;
> + if (kbd_set_level(&new_state, value))
> + return;
> + kbd_set_state_safe(&new_state, &state);
> + } else if (kbd_get_valid_token_counts()) {
> + for (num = kbd_token_bits; num != 0 && value > 0; --value)
> + num &= num - 1; /* clear the first bit set */
> + if (num == 0)
> + return;
> + kbd_set_token_bit(ffs(num) - 1);
> + } else {
> + pr_warn("Keyboard brightness level control not supported\n");
> + }
> +}
> +
> +static struct led_classdev kbd_led = {
> + .name = "dell::kbd_backlight",
> + .brightness_set = kbd_led_level_set,
> + .brightness_get = kbd_led_level_get,
> + .groups = kbd_led_groups,
> +};
> +
> +static int __init kbd_led_init(struct device *dev)
> +{
> + kbd_init();
> + if (!kbd_led_present)
> + return -ENODEV;
> + kbd_led.max_brightness = kbd_get_max_level();
> + if (!kbd_led.max_brightness) {
> + kbd_led.max_brightness = kbd_get_valid_token_counts();
> + if (kbd_led.max_brightness)
> + kbd_led.max_brightness--;
> + }
> + return led_classdev_register(dev, &kbd_led);
> +}
> +
> +static void brightness_set_exit(struct led_classdev *led_cdev,
> + enum led_brightness value)
> +{
> + /* Don't change backlight level on exit */
> +};
> +
> +static void kbd_led_exit(void)
> +{
> + if (!kbd_led_present)
> + return;
> + kbd_led.brightness_set = brightness_set_exit;
> + led_classdev_unregister(&kbd_led);
> +}
> +
> static int __init dell_init(void)
> {
> int max_intensity = 0;
> @@ -842,6 +1830,8 @@ static int __init dell_init(void)
> if (quirks && quirks->touchpad_led)
> touchpad_led_init(&platform_device->dev);
>
> + kbd_led_init(&platform_device->dev);
> +
> dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);
> if (dell_laptop_dir != NULL)
> debugfs_create_file("rfkill", 0444, dell_laptop_dir, NULL,
> @@ -909,6 +1899,7 @@ static void __exit dell_exit(void)
> debugfs_remove_recursive(dell_laptop_dir);
> if (quirks && quirks->touchpad_led)
> touchpad_led_exit();
> + kbd_led_exit();
> i8042_remove_filter(dell_laptop_i8042_filter);
> cancel_delayed_work_sync(&dell_rfkill_work);
> backlight_device_unregister(dell_backlight_device);
> @@ -925,5 +1916,7 @@ module_init(dell_init);
> module_exit(dell_exit);
>
> MODULE_AUTHOR("Matthew Garrett <mjg@xxxxxxxxxx>");
> +MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@xxxxxxxxx>");
> +MODULE_AUTHOR("Pali Rohár <pali.rohar@xxxxxxxxx>");
> MODULE_DESCRIPTION("Dell laptop driver");
> MODULE_LICENSE("GPL");
> --
> 1.7.9.5
>
>

--
Darren Hart
Intel Open Source Technology Center
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