[RFC PATCH RESEND 2/3] leds: upboard: Add LED support

[Javier Arteaga <javier@emutex.com>]

Allow userspace to use the on-board LEDs as "upboard:<color>:".

Signed-off-by: Javier Arteaga <javier@emutex.com>
---
 drivers/leds/Kconfig        | 10 +++++
 drivers/leds/Makefile       |  1 +
 drivers/leds/leds-upboard.c | 87 +++++++++++++++++++++++++++++++++++++
 drivers/mfd/upboard.c       | 19 ++++++++
 include/linux/mfd/upboard.h |  5 +++
 5 files changed, 122 insertions(+)
 create mode 100644 drivers/leds/leds-upboard.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 2c896c0e69e1..2e77b46f2802 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -722,6 +722,16 @@ config LEDS_NIC78BX
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-nic78bx.
 
+config LEDS_UPBOARD
+	tristate "LED support for the UP Squared"
+	depends on LEDS_CLASS
+	depends on MFD_UPBOARD
+	help
+	  This option enables support for the LEDs on the UP Squared board.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called leds-upboard.
+
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 91eca81cae82..4008e2061e1f 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -76,6 +76,7 @@ obj-$(CONFIG_LEDS_MLXREG)		+= leds-mlxreg.o
 obj-$(CONFIG_LEDS_NIC78BX)		+= leds-nic78bx.o
 obj-$(CONFIG_LEDS_MT6323)		+= leds-mt6323.o
 obj-$(CONFIG_LEDS_LM3692X)		+= leds-lm3692x.o
+obj-$(CONFIG_LEDS_UPBOARD)		+= leds-upboard.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
diff --git a/drivers/leds/leds-upboard.c b/drivers/leds/leds-upboard.c
new file mode 100644
index 000000000000..e9d7a1fbcde4
--- /dev/null
+++ b/drivers/leds/leds-upboard.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * UP Board LED driver
+ *
+ * Copyright (c) 2018, Emutex Ltd.
+ *
+ * Author: Javier Arteaga <javier@emutex.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/mfd/upboard.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+struct upboard_led {
+	struct regmap_field *field;
+	struct led_classdev cdev;
+};
+
+static enum led_brightness upboard_led_brightness_get(struct led_classdev *cdev)
+{
+	struct upboard_led *led = container_of(cdev, struct upboard_led, cdev);
+	int brightness = 0;
+
+	regmap_field_read(led->field, &brightness);
+
+	return brightness;
+};
+
+static void upboard_led_brightness_set(struct led_classdev *cdev,
+				       enum led_brightness brightness)
+{
+	struct upboard_led *led = container_of(cdev, struct upboard_led, cdev);
+
+	regmap_field_write(led->field, brightness != LED_OFF);
+};
+
+static int __init upboard_led_probe(struct platform_device *pdev)
+{
+	struct upboard_led_data * const pdata = pdev->dev.platform_data;
+	struct upboard *upboard;
+	struct upboard_led *led;
+	struct reg_field conf = {
+		.reg = UPBOARD_REG_FUNC_EN0,
+	};
+
+	if (!pdev->dev.parent)
+		return -EINVAL;
+
+	upboard = dev_get_drvdata(pdev->dev.parent);
+	if (!upboard || !pdata)
+		return -EINVAL;
+
+	led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+
+	conf.lsb = pdata->id;
+	conf.msb = pdata->id;
+	led->field = devm_regmap_field_alloc(&pdev->dev, upboard->regmap, conf);
+	if (IS_ERR(led->field))
+		return PTR_ERR(led->field);
+
+	led->cdev.brightness_get = upboard_led_brightness_get;
+	led->cdev.brightness_set = upboard_led_brightness_set;
+	led->cdev.name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "upboard:%s:",
+					pdata->color);
+	if (!led->cdev.name)
+		return -ENOMEM;
+
+	return devm_led_classdev_register(&pdev->dev, &led->cdev);
+};
+
+static struct platform_driver upboard_led_driver = {
+	.driver = {
+		.name = "upboard-led",
+	},
+};
+
+module_platform_driver_probe(upboard_led_driver, upboard_led_probe);
+
+MODULE_ALIAS("platform:upboard-led");
+MODULE_AUTHOR("Javier Arteaga <javier@emutex.com>");
+MODULE_DESCRIPTION("UP Board LED driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mfd/upboard.c b/drivers/mfd/upboard.c
index 8bae450cb83d..6e4767e4dc41 100644
--- a/drivers/mfd/upboard.c
+++ b/drivers/mfd/upboard.c
@@ -79,6 +79,14 @@ struct upboard_data {
 	size_t ncells;
 };
 
+#define UPBOARD_LED_CELL(led_data, n)                   \
+	{                                               \
+		.name = "upboard-led",                  \
+		.id = (n),                              \
+		.platform_data = &led_data[(n)],        \
+		.pdata_size = sizeof(*(led_data)),      \
+	}
+
 /* UP Squared */
 
 static const struct regmap_range upboard_up2_readable_ranges[] = {
@@ -116,7 +124,18 @@ static const struct regmap_config upboard_up2_regmap_config = {
 	.wr_table = &upboard_up2_writable_table,
 };
 
+static struct upboard_led_data upboard_up2_led_data[] = {
+	{ .id = 0, .color = "blue" },
+	{ .id = 1, .color = "yellow" },
+	{ .id = 2, .color = "green" },
+	{ .id = 3, .color = "red" },
+};
+
 static const struct mfd_cell upboard_up2_mfd_cells[] = {
+	UPBOARD_LED_CELL(upboard_up2_led_data, 0),
+	UPBOARD_LED_CELL(upboard_up2_led_data, 1),
+	UPBOARD_LED_CELL(upboard_up2_led_data, 2),
+	UPBOARD_LED_CELL(upboard_up2_led_data, 3),
 };
 
 static const struct upboard_data upboard_up2_data = {
diff --git a/include/linux/mfd/upboard.h b/include/linux/mfd/upboard.h
index d9dd214f4d29..eed68caa23ce 100644
--- a/include/linux/mfd/upboard.h
+++ b/include/linux/mfd/upboard.h
@@ -62,4 +62,9 @@ struct upboard {
 	struct gpio_desc *dataout_gpio;
 };
 
+struct upboard_led_data {
+	unsigned int id;
+	const char *color;
+};
+
 #endif /*  __LINUX_MFD_UPBOARD_H */
-- 
2.17.0