From: Christian Mauderer <oss@xxxxxxxxxxxxx>
This driver adds support for the custom LED controller used in Ubiquity
airCube ISP devices and most likely some other simmilar Ubiquity
products.
Signed-off-by: Christian Mauderer <oss@xxxxxxxxxxxxx>
---
drivers/leds/Kconfig | 10 +++
drivers/leds/Makefile | 1 +
drivers/leds/leds-ubnt-spi.c | 140 +++++++++++++++++++++++++++++++++++
3 files changed, 151 insertions(+)
create mode 100644 drivers/leds/leds-ubnt-spi.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a72f97fca57b..e96ab93860ec 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -766,6 +766,16 @@ config LEDS_NIC78BX
To compile this driver as a module, choose M here: the module
will be called leds-nic78bx.
+config LEDS_UBNT_SPI
+ tristate "LED support for Ubnt aircube ISP custom SPI LED controller"
+ depends on LEDS_CLASS
+ depends on SPI
+ depends on OF
+ help
+ This option enables basic support for the LED controller used in
+ Ubiquity airCube ISP devices. The controller is microcontroller based
+ and uses a single byte on the SPI to set brightness or blink patterns.
+
comment "LED Triggers"
source "drivers/leds/trigger/Kconfig"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 4c1b0054f379..f272bfac109c 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_LEDS_PM8058) += leds-pm8058.o
obj-$(CONFIG_LEDS_MLXCPLD) += leds-mlxcpld.o
obj-$(CONFIG_LEDS_MLXREG) += leds-mlxreg.o
obj-$(CONFIG_LEDS_NIC78BX) += leds-nic78bx.o
+obj-$(CONFIG_LEDS_UBNT_SPI) += leds-ubnt-spi.o
obj-$(CONFIG_LEDS_MT6323) += leds-mt6323.o
obj-$(CONFIG_LEDS_LM3692X) += leds-lm3692x.o
obj-$(CONFIG_LEDS_SC27XX_BLTC) += leds-sc27xx-bltc.o
diff --git a/drivers/leds/leds-ubnt-spi.c b/drivers/leds/leds-ubnt-spi.c
new file mode 100644
index 000000000000..a3cb0dd5b0da
--- /dev/null
+++ b/drivers/leds/leds-ubnt-spi.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Christian Mauderer <oss@xxxxxxxxxxxxx>
+
+/*
+ * Custom controller based LED controller used in Ubiquity airCube ISP.
+ *
+ * Reverse engineered protocol:
+ * - The device uses only a single byte sent via SPI.
+ * - The SPI input doesn't contain any relevant information.
+ * - Higher two bits set a mode. Lower six bits are a parameter.
+ * - Mode: 00 -> set brightness between 0x00 (min) and 0x3F (max)
+ * - Mode: 01 -> pulsing pattern (min -> max -> min) with an interval. From
+ * some tests, the period is about (50ms + 102ms * parameter). There is a
+ * slightly different pattern starting from 0x100 (longer gap between the
+ * pulses) but the time still follows that calculation.
+ * - Mode: 10 -> same as 01 but with only a ramp from min to max. Again a
+ * slight jump in the pattern at 0x100.
+ * - Mode: 11 -> blinking (off -> 25% -> off -> 25% -> ...) with a period of
+ * (105ms * parameter)
+ *
+ * NOTE: This driver currently only implements mode 00 (brightness).
+ */
+
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+#include <linux/mutex.h>
+#include <uapi/linux/uleds.h>
+
+#define UBNT_SPI_OFF_BRIGHTNESS 0x0
+#define UBNT_SPI_MAX_BRIGHTNESS 0x3F
+
+struct ubnt_spi_led {
+ struct led_classdev ldev;
+ struct spi_device *spi;
+ char name[LED_MAX_NAME_SIZE];
+ struct mutex mutex;
+ u8 off_bright;
+ u8 max_bright;
+};
+
+static int ubnt_spi_brightness_set_blocking(struct led_classdev *dev,
+ enum led_brightness brightness)
+{
+ struct ubnt_spi_led *led = container_of(dev, struct ubnt_spi_led, ldev);
+ u8 value;
+ int ret;
+
+ value = (u8) brightness + led->off_bright;
+
+ mutex_lock(&led->mutex);
+ ret = spi_write(led->spi, &value, sizeof(value));
+ mutex_unlock(&led->mutex);
+
+ return ret;
+}
+
+static int ubnt_spi_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct device_node *child;
+ struct ubnt_spi_led *led;
+ int ret;
+ const char *tmp;
+ const char *default_name = ":";
+
+ if (!dev->of_node)
+ return -ENODEV;
+
+ if (of_get_child_count(dev->of_node) != 1) {
+ dev_err(dev, "Device must have exactly one LED sub-node.");
+ return -EINVAL;
+ }
+ child = of_get_next_child(dev->of_node, NULL);
+
+ led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
+ if (!led)
+ return -ENOMEM;
+
+ led->spi = spi;
+
+ ret = of_property_read_string(child, "label", &tmp);
+ if (ret < 0)
+ tmp = default_name;
+ snprintf(led->name, sizeof(led->name), "ubnt-spi-led:%s", tmp);
+
+ ret = of_property_read_u8(child, "ubnt-spi,off_bright",
+ &led->off_bright);
+ if (ret != 0)
+ led->off_bright = UBNT_SPI_OFF_BRIGHTNESS;
+
+ ret = of_property_read_u8(child, "ubnt-spi,max_bright",
+ &led->max_bright);
+ if (ret != 0)
+ led->max_bright = UBNT_SPI_MAX_BRIGHTNESS;
+
+ mutex_init(&led->mutex);
+ led->ldev.name = led->name;
+ led->ldev.brightness = LED_OFF;
+ led->ldev.max_brightness = led->max_bright - led->off_bright;
+ led->ldev.brightness_set_blocking = ubnt_spi_brightness_set_blocking;
+ ret = led_classdev_register(&spi->dev, &led->ldev);
+ if (ret >= 0)
+ spi_set_drvdata(spi, led);
+
+ return ret;
+}
+
+static int ubnt_spi_remove(struct spi_device *spi)
+{
+ struct ubnt_spi_led *led = spi_get_drvdata(spi);
+
+ led_classdev_unregister(&led->ldev);
+
+ return 0;
+}
+
+static const struct of_device_id ubnt_spi_dt_ids[] = {
+ { .compatible = "ubnt,spi-led", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, ubnt_spi_dt_ids);
+
+static struct spi_driver ubnt_spi_driver = {
+ .probe = ubnt_spi_probe,
+ .remove = ubnt_spi_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = ubnt_spi_dt_ids,
+ },
+};
+
+module_spi_driver(ubnt_spi_driver);
+
+MODULE_AUTHOR("Christian Mauderer <oss@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Ubnt AirCube ISP LED driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("spi:ubnt-spi-led");
--
2.21.0
