From: Peter Vasil <peter.vasil@xxxxxxxxx>
Nokia Tahvo/Betty ASIC is a companion chip for mobile devices. One of
its outputs is a 127-levels PWM, usually used for LED or backlight
control.
Register control code has been written based on original Nokia kernel
sources for N810 display driver.
Driver expects a regmap device as parent, usually retu-mfd driver bound
to the Tahvo ASIC.
---
drivers/leds/Kconfig | 12 ++++++
drivers/leds/Makefile | 1 +
drivers/leds/leds-tahvo.c | 85 +++++++++++++++++++++++++++++++++++++++
3 files changed, 98 insertions(+)
create mode 100644 drivers/leds/leds-tahvo.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index ed800f5da7d8..010d455a2151 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -871,6 +871,18 @@ config LEDS_ACER_A500
This option enables support for the Power Button LED of
Acer Iconia Tab A500.
+config LEDS_TAHVO
+ tristate "Tahvo PWM led support"
+ depends on LEDS_CLASS && MFD_RETU
+ help
+ Tahvo PWM LED driver for Nokia Internet Tablets (770, N800,
+ N810). At least on N810 the LCD backlight is controlled by
+ Tahvo/Betty MFD.
+
+ To compile this driver as a module, choose M here: the
+ module will be called leds-tahvo.
+
+
source "drivers/leds/blink/Kconfig"
comment "Flash and Torch LED drivers"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index c636ec069612..30832d3bc947 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_LEDS_TURRIS_OMNIA) += leds-turris-omnia.o
obj-$(CONFIG_LEDS_WM831X_STATUS) += leds-wm831x-status.o
obj-$(CONFIG_LEDS_WM8350) += leds-wm8350.o
obj-$(CONFIG_LEDS_WRAP) += leds-wrap.o
+obj-$(CONFIG_LEDS_TAHVO) += leds-tahvo.o
# LED SPI Drivers
obj-$(CONFIG_LEDS_CR0014114) += leds-cr0014114.o
diff --git a/drivers/leds/leds-tahvo.c b/drivers/leds/leds-tahvo.c
new file mode 100644
index 000000000000..53feb0749e76
--- /dev/null
+++ b/drivers/leds/leds-tahvo.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Tahvo LED PWM driver
+ *
+ * Copyright (C) 2004, 2005 Nokia Corporation
+ *
+ * Based on original 2.6 kernel driver for Nokia N8x0 LCD panel.
+ * Rewritten by Peter Vasil.
+ */
+
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#define TAHVO_REG_LEDPWM 0x05
+
+/* Maximum power/brightness value */
+#define TAHVO_LEDPWM_MAX 127
+
+struct tahvo_led {
+ struct led_classdev cdev;
+ struct regmap *regmap;
+};
+
+static int tahvo_led_brightness_set(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct tahvo_led *led = container_of(cdev, struct tahvo_led, cdev);
+
+ return regmap_write(led->regmap, TAHVO_REG_LEDPWM, brightness);
+}
+
+static int tahvo_led_probe(struct platform_device *pdev)
+{
+ struct tahvo_led *led;
+ struct led_init_data init_data;
+ int ret;
+
+ led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
+ if (!led)
+ return -ENOMEM;
+
+ if (pdev->dev.of_node && pdev->dev.of_node->name) {
+ led->cdev.name = pdev->dev.of_node->name;
+ } else {
+ dev_warn(&pdev->dev, "No OF node found, using default name!\n");
+ led->cdev.name = "tahvo:led";
+ }
+
+ led->cdev.max_brightness = TAHVO_LEDPWM_MAX;
+ led->cdev.brightness_set_blocking = tahvo_led_brightness_set;
+
+ led->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+
+ init_data.fwnode = of_fwnode_handle(pdev->dev.of_node);
+
+ ret = devm_led_classdev_register_ext(&pdev->dev, &led->cdev, &init_data);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register PWM LED (%d)\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id of_tahvo_leds_match[] = {
+ { .compatible = "nokia,tahvo-ledpwm", },
+ {},
+};
+
+static struct platform_driver tahvo_led_driver = {
+ .probe = tahvo_led_probe,
+ .driver = {
+ .name = "tahvo-ledpwm",
+ .of_match_table = of_match_ptr(of_tahvo_leds_match),
+ },
+};
+module_platform_driver(tahvo_led_driver);
+
+MODULE_ALIAS("platform:tahvo-ledpwm");
+MODULE_DESCRIPTION("Tahvo LED PWM");
+MODULE_AUTHOR("Peter Vasil <peter.vasil@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.25.1
