leds: Added driver for the NXP PCA9685 I2C chip

The NXP PCA9685 supports 16 channels/leds using a 12-bit PWM (4095
levels of brightness)
This driver supports configuration using platform_data.

Signed-off-by: Maximilian Güntner <maximilian.guentner@gmail.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

3 files changed, 224 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 875bbe4c962e..72156c123033 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -300,6 +300,16 @@ config LEDS_PCA963X
           LED driver chip accessed via the I2C bus. Supported
           devices include PCA9633 and PCA9634
 
+config LEDS_PCA9685
+        tristate "LED support for PCA9685 I2C chip"
+        depends on LEDS_CLASS
+        depends on I2C
+        help
+          This option enables support for LEDs connected to the PCA9685
+          LED driver chip accessed via the I2C bus.
+          The PCA9685 offers 12-bit PWM (4095 levels of brightness) on
+          16 individual channels.
+
 config LEDS_WM831X_STATUS
         tristate "LED support for status LEDs on WM831x PMICs"
         depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 8979b0b2c85e..3cd76dbd9be2 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_LEDS_OT200)		+= leds-ot200.o
 obj-$(CONFIG_LEDS_FSG)                  += leds-fsg.o
 obj-$(CONFIG_LEDS_PCA955X)              += leds-pca955x.o
 obj-$(CONFIG_LEDS_PCA963X)              += leds-pca963x.o
+obj-$(CONFIG_LEDS_PCA9685)              += leds-pca9685.o
 obj-$(CONFIG_LEDS_DA903X)               += leds-da903x.o
 obj-$(CONFIG_LEDS_DA9052)               += leds-da9052.o
 obj-$(CONFIG_LEDS_WM831X_STATUS)        += leds-wm831x-status.o
diff --git a/drivers/leds/leds-pca9685.c b/drivers/leds/leds-pca9685.c
new file mode 100644
index 000000000000..6e1ef3a9d6ef
--- /dev/null
+++ b/drivers/leds/leds-pca9685.c
@@ -0,0 +1,213 @@
+/*
+ * Copyright 2013 Maximilian Güntner <maximilian.guentner@gmail.com>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Based on leds-pca963x.c driver by
+ * Peter Meerwald <p.meerwald@bct-electronic.com>
+ *
+ * Driver for the NXP PCA9685 12-Bit PWM LED driver chip.
+ *
+ */
+
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/workqueue.h>
+
+#include <linux/platform_data/leds-pca9685.h>
+
+/* Register Addresses */
+#define PCA9685_MODE1 0x00
+#define PCA9685_MODE2 0x01
+#define PCA9685_LED0_ON_L 0x06
+#define PCA9685_ALL_LED_ON_L 0xFA
+
+/* MODE1 Register */
+#define PCA9685_ALLCALL 0x00
+#define PCA9685_SLEEP   0x04
+#define PCA9685_AI      0x05
+
+/* MODE2 Register */
+#define PCA9685_INVRT   0x04
+#define PCA9685_OUTDRV  0x02
+
+static const struct i2c_device_id pca9685_id[] = {
+        { "pca9685", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, pca9685_id);
+
+struct pca9685_led {
+        struct i2c_client *client;
+        struct work_struct work;
+        u16 brightness;
+        struct led_classdev led_cdev;
+        int led_num; /* 0-15 */
+        char name[32];
+};
+
+static void pca9685_write_msg(struct i2c_client *client, u8 *buf, u8 len)
+{
+        struct i2c_msg msg = {
+                .addr = client->addr,
+                .flags = 0x00,
+                .len = len,
+                .buf = buf
+        };
+        i2c_transfer(client->adapter, &msg, 1);
+}
+
+static void pca9685_all_off(struct i2c_client *client)
+{
+        u8 i2c_buffer[5] = {PCA9685_ALL_LED_ON_L, 0x00, 0x00, 0x00, 0x10};
+        pca9685_write_msg(client, i2c_buffer, 5);
+}
+
+static void pca9685_led_work(struct work_struct *work)
+{
+        struct pca9685_led *pca9685;
+        u8 i2c_buffer[5];
+
+        pca9685 = container_of(work, struct pca9685_led, work);
+        i2c_buffer[0] = PCA9685_LED0_ON_L + 4 * pca9685->led_num;
+        /*
+         * 4095 is the maximum brightness, so we set the ON time to 0x1000
+         * which disables the PWM generator for that LED
+         */
+        if (pca9685->brightness == 4095)
+                *((__le16 *)(i2c_buffer+1)) = cpu_to_le16(0x1000);
+        else
+                *((__le16 *)(i2c_buffer+1)) = 0x0000;
+
+        if (pca9685->brightness == 0)
+                *((__le16 *)(i2c_buffer+3)) = cpu_to_le16(0x1000);
+        else if (pca9685->brightness == 4095)
+                *((__le16 *)(i2c_buffer+3)) = 0x0000;
+        else
+                *((__le16 *)(i2c_buffer+3)) = cpu_to_le16(pca9685->brightness);
+
+        pca9685_write_msg(pca9685->client, i2c_buffer, 5);
+}
+
+static void pca9685_led_set(struct led_classdev *led_cdev,
+                enum led_brightness value)
+{
+        struct pca9685_led *pca9685;
+        pca9685 = container_of(led_cdev, struct pca9685_led, led_cdev);
+        pca9685->brightness = value;
+
+        schedule_work(&pca9685->work);
+}
+
+static int pca9685_probe(struct i2c_client *client,
+                const struct i2c_device_id *id)
+{
+        struct pca9685_led *pca9685;
+        struct pca9685_platform_data *pdata;
+        int err;
+        u8 i;
+
+        pdata = dev_get_platdata(&client->dev);
+        if (pdata) {
+                if (pdata->leds.num_leds < 1 || pdata->leds.num_leds > 15) {
+                        dev_err(&client->dev, "board info must claim 1-16 LEDs");
+                        return -EINVAL;
+                }
+        }
+
+        pca9685 = devm_kzalloc(&client->dev, 16 * sizeof(*pca9685), GFP_KERNEL);
+        if (!pca9685)
+                return -ENOMEM;
+
+        i2c_set_clientdata(client, pca9685);
+        pca9685_all_off(client);
+
+        for (i = 0; i < 16; i++) {
+                pca9685[i].client = client;
+                pca9685[i].led_num = i;
+                pca9685[i].name[0] = '\0';
+                if (pdata && i < pdata->leds.num_leds) {
+                        if (pdata->leds.leds[i].name)
+                                strncpy(pca9685[i].name,
+                                        pdata->leds.leds[i].name,
+                                        sizeof(pca9685[i].name)-1);
+                        if (pdata->leds.leds[i].default_trigger)
+                                pca9685[i].led_cdev.default_trigger =
+                                        pdata->leds.leds[i].default_trigger;
+                }
+                if (strlen(pca9685[i].name) == 0) {
+                        /*
+                         * Write adapter and address to the name as well.
+                         * Otherwise multiple chips attached to one host would
+                         * not work.
+                         */
+                        snprintf(pca9685[i].name, sizeof(pca9685[i].name),
+                                        "pca9685:%d:x%.2x:%d",
+                                        client->adapter->nr, client->addr, i);
+                }
+                pca9685[i].led_cdev.name = pca9685[i].name;
+                pca9685[i].led_cdev.max_brightness = 0xfff;
+                pca9685[i].led_cdev.brightness_set = pca9685_led_set;
+
+                INIT_WORK(&pca9685[i].work, pca9685_led_work);
+                err = led_classdev_register(&client->dev, &pca9685[i].led_cdev);
+                if (err < 0)
+                        goto exit;
+        }
+
+        if (pdata)
+                i2c_smbus_write_byte_data(client, PCA9685_MODE2,
+                        pdata->outdrv << PCA9685_OUTDRV |
+                        pdata->inverted << PCA9685_INVRT);
+        else
+                i2c_smbus_write_byte_data(client, PCA9685_MODE2,
+                        PCA9685_TOTEM_POLE << PCA9685_OUTDRV);
+        /* Enable Auto-Increment, enable oscillator, ALLCALL/SUBADDR disabled */
+        i2c_smbus_write_byte_data(client, PCA9685_MODE1, BIT(PCA9685_AI));
+
+        return 0;
+
+exit:
+        while (i--) {
+                led_classdev_unregister(&pca9685[i].led_cdev);
+                cancel_work_sync(&pca9685[i].work);
+        }
+        return err;
+}
+
+static int pca9685_remove(struct i2c_client *client)
+{
+        struct pca9685_led *pca9685 = i2c_get_clientdata(client);
+        u8 i;
+
+        for (i = 0; i < 16; i++) {
+                led_classdev_unregister(&pca9685[i].led_cdev);
+                cancel_work_sync(&pca9685[i].work);
+        }
+        pca9685_all_off(client);
+        return 0;
+}
+
+static struct i2c_driver pca9685_driver = {
+        .driver = {
+                .name = "leds-pca9685",
+                .owner = THIS_MODULE,
+        },
+        .probe = pca9685_probe,
+        .remove = pca9685_remove,
+        .id_table = pca9685_id,
+};
+
+module_i2c_driver(pca9685_driver);
+
+MODULE_AUTHOR("Maximilian Güntner <maximilian.guentner@gmail.com>");
+MODULE_DESCRIPTION("PCA9685 LED Driver");
+MODULE_LICENSE("GPL v2");