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Date:   Sun, 16 Oct 2022 15:00:12 +0000
To:     pavel@ucw.cz, jansimon.moeller@gmx.de
From:   Joseph Strauss <jstrauss16@proton.me>
Cc:     linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
        Joseph Strauss <jstrauss16@proton.me>
Subject: [PATCH] Add multicolor support to BlinkM LED driver
Message-ID: <20221016145827.8516-1-jstrauss16@proton.me>
Feedback-ID: 52406082:user:proton
MIME-Version: 1.0
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Precedence: bulk

Added multicolor support to the BlinkM driver, making it easier to
control from userspace. The BlinkM LED is a programmable RGB LED. The
driver currently supports only the regular LED sysfs class, resulting in
the creation of three distinct classes, one for red, green, and blue.
The user then has to input three values into the three seperate
brightness files within those classes. The multicolor LED framework
makes the device easier to control with the multi_intensity file: the
user can input three values at once to form a color, while still
controlling the lightness with the brightness file.

The main struct blinkm_led has changed slightly. A struct
led_classdev_mc has been added to represent the multicolor sysfs class,
and an additional struct led_classdev pointer has been added for
convenience, which points to the struct led_classdev within struct
led_classdev_mc. The struct led_classdev for the regular sysfs classes
remain. Additionally, a field representing the multicolor LED has been
added to the struct blinkm_data, seperate from the blinkm_leds[3] array.

In the blinkm_probe function, the multicolor LED class is registered
after the regular LED classes. The blinkm_set_brightness_mc() function
had to be added to calculate the three color components and then set the
fields of the blinkm_data structure accordingly.

Signed-off-by: Joseph Strauss <jstrauss16@proton.me>

---
 Documentation/leds/leds-blinkm.rst |  24 ++++-
 drivers/leds/Kconfig               |   1 +
 drivers/leds/leds-blinkm.c         | 154 ++++++++++++++++++++++++-----
 3 files changed, 151 insertions(+), 28 deletions(-)

diff --git a/Documentation/leds/leds-blinkm.rst b/Documentation/leds/leds-b=
linkm.rst
index c74b5bc877b1..3f5dbd5e97b0 100644
--- a/Documentation/leds/leds-blinkm.rst
+++ b/Documentation/leds/leds-blinkm.rst
@@ -13,9 +13,27 @@ The device accepts RGB and HSB color values through sepa=
rate commands.
 Also you can store blinking sequences as "scripts" in
 the controller and run them. Also fading is an option.

-The interface this driver provides is 2-fold:
+The interface this driver provides is 3-fold:

-a) LED class interface for use with triggers
+a) LED multicolor class interface for use with triggers
+#######################################################
+
+The registration follows the scheme::
+
+  blinkm-<i2c-bus-nr>-<i2c-device-nr>-multi
+
+  $ ls -h /sys/class/leds/blinkm-1-9-multi
+  brightness  device  max_brightness  multi_index  multi_intensity  power =
 subsystem  trigger  uevent
+
+The order in which to write the intensity values can be found in multi_ind=
ex.
+Exactly three values between 0 and 255 must be written to multi_intensity =
to change the color::
+
+  $ echo 255 100 50 > multi_intensity
+
+The overall brightness of the color that you choose can also be changed by
+writing a value between 0 and 255 to the brightness file.
+
+b) LED class interface for use with triggers
 ############################################

 The registration follows the scheme::
@@ -50,7 +68,7 @@ E.g.::
   $


-b) Sysfs group to control rgb, fade, hsb, scripts ...
+c) Sysfs group to control rgb, fade, hsb, scripts ...
 #####################################################

 This extended interface is available as folder blinkm
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 499d0f215a8b..710a34e9f398 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -731,6 +731,7 @@ comment "LED driver for blink(1) USB RGB LED is under S=
pecial HID drivers (HID_T
 config LEDS_BLINKM
 =09tristate "LED support for the BlinkM I2C RGB LED"
 =09depends on LEDS_CLASS
+=09depends on LEDS_CLASS_MULTICOLOR
 =09depends on I2C
 =09help
 =09  This option enables support for the BlinkM RGB LED connected
diff --git a/drivers/leds/leds-blinkm.c b/drivers/leds/leds-blinkm.c
index bd7d0d5cf3b6..afebe2b12ad5 100644
--- a/drivers/leds/leds-blinkm.c
+++ b/drivers/leds/leds-blinkm.c
@@ -15,6 +15,9 @@
 #include <linux/pm_runtime.h>
 #include <linux/leds.h>
 #include <linux/delay.h>
+#include <linux/led-class-multicolor.h>
+
+#define NUM_LEDS 3

 /* Addresses to scan - BlinkM is on 0x09 by default*/
 static const unsigned short normal_i2c[] =3D { 0x09, I2C_CLIENT_END };
@@ -22,19 +25,26 @@ static const unsigned short normal_i2c[] =3D { 0x09, I2=
C_CLIENT_END };
 static int blinkm_transfer_hw(struct i2c_client *client, int cmd);
 static int blinkm_test_run(struct i2c_client *client);

+/* Contains data structures for both the color-seperated sysfs classes, an=
d the new multicolor class */
 struct blinkm_led {
 =09struct i2c_client *i2c_client;
-=09struct led_classdev led_cdev;
+=09struct led_classdev monochrome_led_cdev;
+=09/* points to struct led_classdev inside of struct led_classdev_mc */
+=09struct led_classdev *led_cdev;
+=09struct led_classdev_mc mcled_cdev;
 =09int id;
 };

-#define cdev_to_blmled(c)          container_of(c, struct blinkm_led, led_=
cdev)
+#define monochrome_led_cdev_to_blmled(c)=09container_of(c, struct blinkm_l=
ed, monochrome_led_cdev)
+#define mcled_cdev_to_led(c)=09=09=09=09container_of(c, struct blinkm_led,=
 mcled_cdev)

 struct blinkm_data {
 =09struct i2c_client *i2c_client;
 =09struct mutex update_lock;
 =09/* used for led class interface */
+=09struct blinkm_led mc_blinkm_led;
 =09struct blinkm_led blinkm_leds[3];
+
 =09/* used for "blinkm" sysfs interface */
 =09u8 red;=09=09=09/* color red */
 =09u8 green;=09=09/* color green */
@@ -260,9 +270,9 @@ static ssize_t test_show(struct device *dev, struct dev=
ice_attribute *attr,
 static ssize_t test_store(struct device *dev, struct device_attribute *att=
r,
 =09=09=09  const char *buf, size_t count)
 {
-
 =09struct i2c_client *client;
 =09int ret;
+
 =09client =3D to_i2c_client(dev);

 =09/*test */
@@ -317,6 +327,7 @@ static int blinkm_read(struct i2c_client *client, int c=
md, u8 *arg)
 =09int result;
 =09int i;
 =09int retlen =3D blinkm_cmds[cmd].nr_ret;
+
 =09for (i =3D 0; i < retlen; i++) {
 =09=09/* repeat for retlen */
 =09=09result =3D i2c_smbus_read_byte(client);
@@ -419,11 +430,53 @@ static int blinkm_transfer_hw(struct i2c_client *clie=
nt, int cmd)
 =09return 0;
 }

+static int blinkm_set_mc_brightness(struct led_classdev *led_cdev,
+=09=09=09=09 enum led_brightness value)
+{
+=09struct led_classdev_mc *mcled_cdev;
+=09struct blinkm_led *led;
+=09struct blinkm_data *data;
+=09int i;
+
+=09mcled_cdev =3D lcdev_to_mccdev(led_cdev);
+=09led =3D mcled_cdev_to_led(mcled_cdev);
+=09data =3D i2c_get_clientdata(led->i2c_client);
+
+=09led_mc_calc_color_components(mcled_cdev, value);
+
+=09for (i =3D 0; i < NUM_LEDS; i++) {
+=09=09switch (i) {
+=09=09case RED:
+=09=09=09if (data->next_red =3D=3D (u8) mcled_cdev->subled_info[i].brightn=
ess)
+=09=09=09=09break;
+=09=09=09data->next_red =3D (u8) mcled_cdev->subled_info[i].brightness;
+=09=09=09break;
+=09=09case GREEN:
+=09=09=09if (data->next_green =3D=3D (u8) mcled_cdev->subled_info[i].brigh=
tness)
+=09=09=09=09break;
+=09=09=09data->next_green =3D (u8) mcled_cdev->subled_info[i].brightness;
+=09=09=09break;
+=09=09case BLUE:
+=09=09=09if (data->next_blue =3D=3D (u8) mcled_cdev->subled_info[i].bright=
ness)
+=09=09=09=09break;
+=09=09=09data->next_blue =3D (u8) mcled_cdev->subled_info[i].brightness;
+=09=09=09break;
+=09=09}
+=09}
+=09blinkm_transfer_hw(led->i2c_client, BLM_GO_RGB);
+=09dev_dbg(&led->i2c_client->dev,
+=09=09=09"# DONE # next_red =3D %d, next_green =3D %d,"
+=09=09=09" next_blue =3D %d\n",
+=09=09=09data->next_red, data->next_green,
+=09=09=09data->next_blue);
+=09return 0;
+}
+
 static int blinkm_led_common_set(struct led_classdev *led_cdev,
 =09=09=09=09 enum led_brightness value, int color)
 {
 =09/* led_brightness is 0, 127 or 255 - we just use it here as-is */
-=09struct blinkm_led *led =3D cdev_to_blmled(led_cdev);
+=09struct blinkm_led *led =3D monochrome_led_cdev_to_blmled(led_cdev);
 =09struct blinkm_data *data =3D i2c_get_clientdata(led->i2c_client);

 =09switch (color) {
@@ -569,7 +622,11 @@ static int blinkm_probe(struct i2c_client *client,
 =09=09=09const struct i2c_device_id *id)
 {
 =09struct blinkm_data *data;
-=09struct blinkm_led *led[3];
+=09/* For multicolor support */
+=09struct blinkm_led *mc_led;
+=09struct mc_subled *mc_led_info;
+=09/* 3 seperate classes for red, green, and blue respectively */
+=09struct blinkm_led *leds[3];
 =09int err, i;
 =09char blinkm_led_name[28];

@@ -580,6 +637,12 @@ static int blinkm_probe(struct i2c_client *client,
 =09=09goto exit;
 =09}

+=09mc_led_info =3D devm_kmalloc_array(&client->dev, 3, sizeof(*mc_led_info=
),
+=09=09=09=09=09GFP_KERNEL | __GFP_ZERO);
+=09if (!mc_led_info) {
+=09=09err =3D -ENOMEM;
+=09=09goto exit;
+=09}
 =09data->i2c_addr =3D 0x08;
 =09/* i2c addr  - use fake addr of 0x08 initially (real is 0x09) */
 =09data->fw_ver =3D 0xfe;
@@ -598,28 +661,30 @@ static int blinkm_probe(struct i2c_client *client,
 =09=09goto exit;
 =09}

+
+=09/* Register red, green, and blue sysfs classes */
 =09for (i =3D 0; i < 3; i++) {
 =09=09/* RED =3D 0, GREEN =3D 1, BLUE =3D 2 */
-=09=09led[i] =3D &data->blinkm_leds[i];
-=09=09led[i]->i2c_client =3D client;
-=09=09led[i]->id =3D i;
-=09=09led[i]->led_cdev.max_brightness =3D 255;
-=09=09led[i]->led_cdev.flags =3D LED_CORE_SUSPENDRESUME;
+=09=09leds[i] =3D &data->blinkm_leds[i];
+=09=09leds[i]->i2c_client =3D client;
+=09=09leds[i]->id =3D i;
+=09=09leds[i]->monochrome_led_cdev.max_brightness =3D 255;
+=09=09leds[i]->monochrome_led_cdev.flags =3D LED_CORE_SUSPENDRESUME;
 =09=09switch (i) {
 =09=09case RED:
 =09=09=09snprintf(blinkm_led_name, sizeof(blinkm_led_name),
 =09=09=09=09=09 "blinkm-%d-%d-red",
 =09=09=09=09=09 client->adapter->nr,
 =09=09=09=09=09 client->addr);
-=09=09=09led[i]->led_cdev.name =3D blinkm_led_name;
-=09=09=09led[i]->led_cdev.brightness_set_blocking =3D
+=09=09=09leds[i]->monochrome_led_cdev.name =3D blinkm_led_name;
+=09=09=09leds[i]->monochrome_led_cdev.brightness_set_blocking =3D
 =09=09=09=09=09=09=09blinkm_led_red_set;
 =09=09=09err =3D led_classdev_register(&client->dev,
-=09=09=09=09=09=09    &led[i]->led_cdev);
+=09=09=09=09=09=09=09&leds[i]->monochrome_led_cdev);
 =09=09=09if (err < 0) {
 =09=09=09=09dev_err(&client->dev,
 =09=09=09=09=09"couldn't register LED %s\n",
-=09=09=09=09=09led[i]->led_cdev.name);
+=09=09=09=09=09leds[i]->monochrome_led_cdev.name);
 =09=09=09=09goto failred;
 =09=09=09}
 =09=09=09break;
@@ -628,15 +693,15 @@ static int blinkm_probe(struct i2c_client *client,
 =09=09=09=09=09 "blinkm-%d-%d-green",
 =09=09=09=09=09 client->adapter->nr,
 =09=09=09=09=09 client->addr);
-=09=09=09led[i]->led_cdev.name =3D blinkm_led_name;
-=09=09=09led[i]->led_cdev.brightness_set_blocking =3D
+=09=09=09leds[i]->monochrome_led_cdev.name =3D blinkm_led_name;
+=09=09=09leds[i]->monochrome_led_cdev.brightness_set_blocking =3D
 =09=09=09=09=09=09=09blinkm_led_green_set;
 =09=09=09err =3D led_classdev_register(&client->dev,
-=09=09=09=09=09=09    &led[i]->led_cdev);
+=09=09=09=09=09=09=09&leds[i]->monochrome_led_cdev);
 =09=09=09if (err < 0) {
 =09=09=09=09dev_err(&client->dev,
 =09=09=09=09=09"couldn't register LED %s\n",
-=09=09=09=09=09led[i]->led_cdev.name);
+=09=09=09=09=09leds[i]->monochrome_led_cdev.name);
 =09=09=09=09goto failgreen;
 =09=09=09}
 =09=09=09break;
@@ -645,34 +710,72 @@ static int blinkm_probe(struct i2c_client *client,
 =09=09=09=09=09 "blinkm-%d-%d-blue",
 =09=09=09=09=09 client->adapter->nr,
 =09=09=09=09=09 client->addr);
-=09=09=09led[i]->led_cdev.name =3D blinkm_led_name;
-=09=09=09led[i]->led_cdev.brightness_set_blocking =3D
+=09=09=09leds[i]->monochrome_led_cdev.name =3D blinkm_led_name;
+=09=09=09leds[i]->monochrome_led_cdev.brightness_set_blocking =3D
 =09=09=09=09=09=09=09blinkm_led_blue_set;
 =09=09=09err =3D led_classdev_register(&client->dev,
-=09=09=09=09=09=09    &led[i]->led_cdev);
+=09=09=09=09=09=09=09&leds[i]->monochrome_led_cdev);
 =09=09=09if (err < 0) {
 =09=09=09=09dev_err(&client->dev,
 =09=09=09=09=09"couldn't register LED %s\n",
-=09=09=09=09=09led[i]->led_cdev.name);
+=09=09=09=09=09leds[i]->monochrome_led_cdev.name);
 =09=09=09=09goto failblue;
 =09=09=09}
 =09=09=09break;
 =09=09}=09=09/* end switch */
 =09}=09=09=09/* end for */

+
+
+=09/* Register multicolor sysfs class */
+=09mc_led =3D &data->mc_blinkm_led;
+=09mc_led->i2c_client =3D client;
+=09mc_led->id =3D 4;
+
+=09mc_led_info[0].color_index =3D LED_COLOR_ID_RED;
+=09mc_led_info[0].channel =3D 0;
+=09mc_led_info[1].color_index =3D LED_COLOR_ID_GREEN;
+=09mc_led_info[1].channel =3D 1;
+=09mc_led_info[2].color_index =3D LED_COLOR_ID_BLUE;
+=09mc_led_info[2].channel =3D 2;
+=09mc_led->mcled_cdev.subled_info =3D mc_led_info;
+=09mc_led->mcled_cdev.num_colors =3D NUM_LEDS;
+
+=09mc_led->led_cdev =3D &mc_led->mcled_cdev.led_cdev;
+=09mc_led->led_cdev->brightness =3D 255;
+=09mc_led->led_cdev->max_brightness =3D 255;
+=09mc_led->led_cdev->flags =3D LED_CORE_SUSPENDRESUME;
+=09snprintf(blinkm_led_name, sizeof(blinkm_led_name),
+=09=09 "blinkm-%d-%d-multi",
+=09=09 client->adapter->nr,
+=09=09 client->addr);
+=09mc_led->led_cdev->name =3D blinkm_led_name;
+=09mc_led->led_cdev->brightness_set_blocking =3D
+=09=09=09=09=09blinkm_set_mc_brightness;
+
+=09err =3D led_classdev_multicolor_register(&client->dev, &mc_led->mcled_c=
dev);
+=09if (err < 0) {
+=09=09dev_err(&client->dev, "couldn't register LED %s\n",
+=09=09=09=09mc_led->led_cdev->name);
+=09=09goto failmulti;
+=09}
 =09/* Initialize the blinkm */
 =09blinkm_init_hw(client);

 =09return 0;

+failmulti:
+=09led_classdev_unregister(&leds[BLUE]->monochrome_led_cdev);
+
 failblue:
-=09led_classdev_unregister(&led[GREEN]->led_cdev);
+=09led_classdev_unregister(&leds[GREEN]->monochrome_led_cdev);

 failgreen:
-=09led_classdev_unregister(&led[RED]->led_cdev);
+=09led_classdev_unregister(&leds[RED]->monochrome_led_cdev);

 failred:
 =09sysfs_remove_group(&client->dev.kobj, &blinkm_group);
+
 exit:
 =09return err;
 }
@@ -684,8 +787,9 @@ static int blinkm_remove(struct i2c_client *client)
 =09int i;

 =09/* make sure no workqueue entries are pending */
+=09led_classdev_unregister(&data->mc_blinkm_led.mcled_cdev.led_cdev);
 =09for (i =3D 0; i < 3; i++)
-=09=09led_classdev_unregister(&data->blinkm_leds[i].led_cdev);
+=09=09led_classdev_unregister(&data->blinkm_leds[i].monochrome_led_cdev);

 =09/* reset rgb */
 =09data->next_red =3D 0x00;
--
2.37.2