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From:   Joseph Strauss <jstrauss@mailbox.org>
To:     pavel@ucw.cz, lee@kernel.org, jansimon.moeller@gmx.de
Cc:     conor@kernel.org, christophe.jaillet@wanadoo.fr,
        linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
        Joseph Strauss <jstrauss@mailbox.org>
Subject: [PATCH v2] Add multicolor support to BlinkM LED driver
Date:   Tue, 27 Dec 2022 19:09:58 -0600
Message-Id: <20221228010958.9670-1-jstrauss@mailbox.org>
MIME-Version: 1.0
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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_mc_brightness() 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 <jstrauss@mailbox.org>
---
Changes in v2:
- Replaced instances of the constant 3 with NUM_LEDS, where applicable
- Fixed formatting errors
- Replaced loop inside of blinkm_set_mc_brightness() with equivalent
  statements
- Changed id of multicolor class from 4 to 3
- Replaced call to devm_kmalloc_array() with devm_kcalloc()

 Documentation/leds/leds-blinkm.rst |  26 +++++-
 drivers/leds/Kconfig               |   1 +
 drivers/leds/leds-blinkm.c         | 143 +++++++++++++++++++++++------
 3 files changed, 137 insertions(+), 33 deletions(-)

diff --git a/Documentation/leds/leds-blinkm.rst b/Documentation/leds/leds-blinkm.rst
index c74b5bc877b1..542a35432c57 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 separate 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_index.
+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
@@ -79,6 +97,6 @@ E.g.::
 
 
 
-as of 6/2012
+as of 12/2022
 
 dl9pf <at> gmx <dot> de
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 499d0f215a8b..8ec06f1f60af 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -731,6 +731,7 @@ comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_T
 config LEDS_BLINKM
 	tristate "LED support for the BlinkM I2C RGB LED"
 	depends on LEDS_CLASS
+    depends on LEDS_CLASS_MULTICOLOR
 	depends on I2C
 	help
 	  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 3fb6a2fdaefa..252b20da7137 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[] = { 0x09, I2C_CLIENT_END };
@@ -22,19 +25,26 @@ static const unsigned short normal_i2c[] = { 0x09, I2C_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, and the new multicolor class */
 struct blinkm_led {
 	struct i2c_client *i2c_client;
-	struct led_classdev led_cdev;
+	struct led_classdev monochrome_led_cdev;
+	/* points to struct led_classdev inside of struct led_classdev_mc */
+	struct led_classdev *led_cdev;
+	struct led_classdev_mc mcled_cdev;
 	int id;
 };
 
-#define cdev_to_blmled(c)          container_of(c, struct blinkm_led, led_cdev)
+#define monochrome_led_cdev_to_blmled(c)	container_of(c, struct blinkm_led, monochrome_led_cdev)
+#define mcled_cdev_to_led(c)				container_of(c, struct blinkm_led, mcled_cdev)
 
 struct blinkm_data {
 	struct i2c_client *i2c_client;
 	struct mutex update_lock;
 	/* used for led class interface */
-	struct blinkm_led blinkm_leds[3];
+	struct blinkm_led mc_blinkm_led;
+	struct blinkm_led blinkm_leds[NUM_LEDS];
+
 	/* used for "blinkm" sysfs interface */
 	u8 red;			/* color red */
 	u8 green;		/* color green */
@@ -419,11 +429,36 @@ static int blinkm_transfer_hw(struct i2c_client *client, int cmd)
 	return 0;
 }
 
+static int blinkm_set_mc_brightness(struct led_classdev *led_cdev,
+				 enum led_brightness value)
+{
+	struct led_classdev_mc *mcled_cdev;
+	struct blinkm_led *led;
+	struct blinkm_data *data;
+
+	mcled_cdev = lcdev_to_mccdev(led_cdev);
+	led = mcled_cdev_to_led(mcled_cdev);
+	data = i2c_get_clientdata(led->i2c_client);
+
+	led_mc_calc_color_components(mcled_cdev, value);
+
+	data->next_red = (u8) mcled_cdev->subled_info[RED].brightness;
+	data->next_green = (u8) mcled_cdev->subled_info[GREEN].brightness;
+	data->next_blue = (u8) mcled_cdev->subled_info[BLUE].brightness;
+
+	blinkm_transfer_hw(led->i2c_client, BLM_GO_RGB);
+	dev_dbg(&led->i2c_client->dev,
+			"# DONE # next_red = %d, next_green = %d, next_blue = %d\n",
+			data->next_red, data->next_green,
+			data->next_blue);
+	return 0;
+}
+
 static int blinkm_led_common_set(struct led_classdev *led_cdev,
 				 enum led_brightness value, int color)
 {
 	/* led_brightness is 0, 127 or 255 - we just use it here as-is */
-	struct blinkm_led *led = cdev_to_blmled(led_cdev);
+	struct blinkm_led *led = monochrome_led_cdev_to_blmled(led_cdev);
 	struct blinkm_data *data = i2c_get_clientdata(led->i2c_client);
 
 	switch (color) {
@@ -480,8 +515,9 @@ static int blinkm_led_blue_set(struct led_classdev *led_cdev,
 
 static void blinkm_init_hw(struct i2c_client *client)
 {
-	blinkm_transfer_hw(client, BLM_STOP_SCRIPT);
-	blinkm_transfer_hw(client, BLM_GO_RGB);
+	int ret;
+	ret = blinkm_transfer_hw(client, BLM_STOP_SCRIPT);
+	ret = blinkm_transfer_hw(client, BLM_GO_RGB);
 }
 
 static int blinkm_test_run(struct i2c_client *client)
@@ -569,7 +605,11 @@ static int blinkm_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct blinkm_data *data;
-	struct blinkm_led *led[3];
+	/* For multicolor support */
+	struct blinkm_led *mc_led;
+	struct mc_subled *mc_led_info;
+	/* 3 seperate classes for red, green, and blue respectively */
+	struct blinkm_led *leds[NUM_LEDS];
 	int err, i;
 	char blinkm_led_name[28];
 
@@ -580,6 +620,12 @@ static int blinkm_probe(struct i2c_client *client,
 		goto exit;
 	}
 
+	mc_led_info = devm_kcalloc(&client->dev, NUM_LEDS, sizeof(*mc_led_info),
+					GFP_KERNEL);
+	if (!mc_led_info) {
+		err = -ENOMEM;
+		goto exit;
+	}
 	data->i2c_addr = 0x08;
 	/* i2c addr  - use fake addr of 0x08 initially (real is 0x09) */
 	data->fw_ver = 0xfe;
@@ -598,28 +644,30 @@ static int blinkm_probe(struct i2c_client *client,
 		goto exit;
 	}
 
-	for (i = 0; i < 3; i++) {
+
+	/* Register red, green, and blue sysfs classes */
+	for (i = 0; i < NUM_LEDS; i++) {
 		/* RED = 0, GREEN = 1, BLUE = 2 */
-		led[i] = &data->blinkm_leds[i];
-		led[i]->i2c_client = client;
-		led[i]->id = i;
-		led[i]->led_cdev.max_brightness = 255;
-		led[i]->led_cdev.flags = LED_CORE_SUSPENDRESUME;
+		leds[i] = &data->blinkm_leds[i];
+		leds[i]->i2c_client = client;
+		leds[i]->id = i;
+		leds[i]->monochrome_led_cdev.max_brightness = 255;
+		leds[i]->monochrome_led_cdev.flags = LED_CORE_SUSPENDRESUME;
 		switch (i) {
 		case RED:
 			snprintf(blinkm_led_name, sizeof(blinkm_led_name),
 					 "blinkm-%d-%d-red",
 					 client->adapter->nr,
 					 client->addr);
-			led[i]->led_cdev.name = blinkm_led_name;
-			led[i]->led_cdev.brightness_set_blocking =
+			leds[i]->monochrome_led_cdev.name = blinkm_led_name;
+			leds[i]->monochrome_led_cdev.brightness_set_blocking =
 							blinkm_led_red_set;
 			err = led_classdev_register(&client->dev,
-						    &led[i]->led_cdev);
+						    &leds[i]->monochrome_led_cdev);
 			if (err < 0) {
 				dev_err(&client->dev,
 					"couldn't register LED %s\n",
-					led[i]->led_cdev.name);
+					leds[i]->monochrome_led_cdev.name);
 				goto failred;
 			}
 			break;
@@ -628,15 +676,15 @@ static int blinkm_probe(struct i2c_client *client,
 					 "blinkm-%d-%d-green",
 					 client->adapter->nr,
 					 client->addr);
-			led[i]->led_cdev.name = blinkm_led_name;
-			led[i]->led_cdev.brightness_set_blocking =
+			leds[i]->monochrome_led_cdev.name = blinkm_led_name;
+			leds[i]->monochrome_led_cdev.brightness_set_blocking =
 							blinkm_led_green_set;
 			err = led_classdev_register(&client->dev,
-						    &led[i]->led_cdev);
+						    &leds[i]->monochrome_led_cdev);
 			if (err < 0) {
 				dev_err(&client->dev,
 					"couldn't register LED %s\n",
-					led[i]->led_cdev.name);
+					leds[i]->monochrome_led_cdev.name);
 				goto failgreen;
 			}
 			break;
@@ -645,34 +693,70 @@ static int blinkm_probe(struct i2c_client *client,
 					 "blinkm-%d-%d-blue",
 					 client->adapter->nr,
 					 client->addr);
-			led[i]->led_cdev.name = blinkm_led_name;
-			led[i]->led_cdev.brightness_set_blocking =
+			leds[i]->monochrome_led_cdev.name = blinkm_led_name;
+			leds[i]->monochrome_led_cdev.brightness_set_blocking =
 							blinkm_led_blue_set;
 			err = led_classdev_register(&client->dev,
-						    &led[i]->led_cdev);
+						    &leds[i]->monochrome_led_cdev);
 			if (err < 0) {
 				dev_err(&client->dev,
 					"couldn't register LED %s\n",
-					led[i]->led_cdev.name);
+					leds[i]->monochrome_led_cdev.name);
 				goto failblue;
 			}
 			break;
 		}		/* end switch */
 	}			/* end for */
 
+	/* Register multicolor sysfs class */
+	mc_led = &data->mc_blinkm_led;
+	mc_led->i2c_client = client;
+	mc_led->id = 3;
+
+	mc_led_info[0].color_index = LED_COLOR_ID_RED;
+	mc_led_info[0].channel = 0;
+	mc_led_info[1].color_index = LED_COLOR_ID_GREEN;
+	mc_led_info[1].channel = 1;
+	mc_led_info[2].color_index = LED_COLOR_ID_BLUE;
+	mc_led_info[2].channel = 2;
+	mc_led->mcled_cdev.subled_info = mc_led_info;
+	mc_led->mcled_cdev.num_colors = NUM_LEDS;
+
+	mc_led->led_cdev = &mc_led->mcled_cdev.led_cdev;
+	mc_led->led_cdev->brightness = 255;
+	mc_led->led_cdev->max_brightness = 255;
+	mc_led->led_cdev->flags = LED_CORE_SUSPENDRESUME;
+	snprintf(blinkm_led_name, sizeof(blinkm_led_name),
+		 "blinkm-%d-%d-multi",
+		 client->adapter->nr,
+		 client->addr);
+	mc_led->led_cdev->name = blinkm_led_name;
+	mc_led->led_cdev->brightness_set_blocking =
+					blinkm_set_mc_brightness;
+
+	err = led_classdev_multicolor_register(&client->dev, &mc_led->mcled_cdev);
+	if (err < 0) {
+		dev_err(&client->dev, "couldn't register LED %s\n",
+				mc_led->led_cdev->name);
+		goto failmulti;
+	}
 	/* Initialize the blinkm */
 	blinkm_init_hw(client);
 
 	return 0;
 
+failmulti:
+	led_classdev_unregister(&leds[BLUE]->monochrome_led_cdev);
+
 failblue:
-	led_classdev_unregister(&led[GREEN]->led_cdev);
+	led_classdev_unregister(&leds[GREEN]->monochrome_led_cdev);
 
 failgreen:
-	led_classdev_unregister(&led[RED]->led_cdev);
+	led_classdev_unregister(&leds[RED]->monochrome_led_cdev);
 
 failred:
 	sysfs_remove_group(&client->dev.kobj, &blinkm_group);
+
 exit:
 	return err;
 }
@@ -684,8 +768,9 @@ static void blinkm_remove(struct i2c_client *client)
 	int i;
 
 	/* make sure no workqueue entries are pending */
-	for (i = 0; i < 3; i++)
-		led_classdev_unregister(&data->blinkm_leds[i].led_cdev);
+	led_classdev_unregister(&data->mc_blinkm_led.mcled_cdev.led_cdev);
+	for (i = 0; i < NUM_LEDS; i++)
+		led_classdev_unregister(&data->blinkm_leds[i].monochrome_led_cdev);
 
 	/* reset rgb */
 	data->next_red = 0x00;
-- 
2.38.1