Date:	Mon, 18 Apr 2016 20:43:16 +0200
From:	"H. Nikolaus Schaller" <hns@...delico.com>
To:	Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Richard Purdie <rpurdie@...ys.net>,
	Jacek Anaszewski <j.anaszewski@...sung.com>,
	"H. Nikolaus Schaller" <hns@...delico.com>
Cc:	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-leds@...r.kernel.org, kernel@...a-handheld.com,
	marek@...delico.com, letux-kernel@...nphoenux.org
Subject: [PATCH] drivers: led: is31fl319x: 6/9-channel light effect led driver

This is a driver for the Integrated Silicon Solution Inc. LED driver
chips IS31FL3196 and IS31FL3199. They can drive up to 6 or 9
LEDs.

Each LED is individually controllable in brightness (through pwm)
in 256 steps so that RGB LEDs can show any of ca. 16 Mio colors.

The maximum current of the LEDs can be programmed and limited to
5 .. 40mA through a device tree property.

The chip is connected through I2C and can have one of 4 addresses (0x64 .. 0x67)
depending on how the AD pin is connected. The address is defined by the
reg property as usual.

The chip also has a shutdown input which could be connected to a GPIO,
but this driver uses software shutdown if all LEDs are inactivated.

The chip also has breathing and audio features which are not supported
by this driver.

This driver was developed and tested on OMAP5 based Pyra handheld prototype.

Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
---
 .../devicetree/bindings/leds/is31fl319x.txt        |  41 +++
 drivers/leds/Kconfig                               |   8 +
 drivers/leds/Makefile                              |   1 +
 drivers/leds/leds-is31fl319x.c                     | 406 +++++++++++++++++++++
 include/linux/leds-is31fl319x.h                    |  24 ++
 5 files changed, 480 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/is31fl319x.txt
 create mode 100644 drivers/leds/leds-is31fl319x.c
 create mode 100644 include/linux/leds-is31fl319x.h

diff --git a/Documentation/devicetree/bindings/leds/is31fl319x.txt b/Documentation/devicetree/bindings/leds/is31fl319x.txt
new file mode 100644
index 0000000..d13c7ca
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/is31fl319x.txt
@@ -0,0 +1,41 @@
+LEDs connected to is31fl319x RGB LED controller chip
+
+Required properties:
+- compatible : should be : "issi,is31fl3196" or "issi,is31fl3199".
+- #address-cells: must be 1
+- #size-cells: must be 0
+- reg: 0x64, 0x65, 0x66, 0x67.
+
+Optional properties:
+- max-current-ma:	maximum led current (5..40 mA, default 20 mA)
+- audio-gain-db:	audio gain selection (0..21 dB. default 0 dB)
+- breathing & audio:	not implemented
+
+Each led is represented as a sub-node of the issi,is31fl319x device.
+
+LED sub-node properties:
+- label : (optional) see Documentation/devicetree/bindings/leds/common.txt
+- reg : number of LED line (0 to 5 or 0 to 8 - not all need to be present)
+- linux,default-trigger : (optional)
+   see Documentation/devicetree/bindings/leds/common.txt
+
+Examples:
+
+fancy_leds: is31fl3196@65 {
+	compatible = "issi,is31fl319x";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x65>;
+
+	led0: red-aux@0 {
+		label = "red:aux";
+		reg = <0>;
+	};
+
+	led1: green-power@4 {
+		label = "green:power";
+		reg = <4>;
+		linux,default-trigger = "default-on";
+	};
+};
+
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 2251478..f099bcb 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -491,6 +491,14 @@ config LEDS_ASIC3
 	  cannot be used. This driver supports hardware blinking with an on+off
 	  period from 62ms to 125s. Say Y to enable LEDs on the HP iPAQ hx4700.
 
+config LEDS_IS31FL319X
+	tristate "LED Support for IS31FL319x I2C chip"
+	depends on LEDS_CLASS && I2C
+	help
+	  This option enables support for LEDs connected to IS31FL3196
+	  or IS31FL3199 LED driver chips accessed via the I2C bus.
+	  Driver support brightness control and hardware-assisted blinking.
+
 config LEDS_TCA6507
 	tristate "LED Support for TCA6507 I2C chip"
 	depends on LEDS_CLASS && I2C
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index cb2013d..eee3010 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o
 obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
 obj-$(CONFIG_LEDS_CLEVO_MAIL)		+= leds-clevo-mail.o
 obj-$(CONFIG_LEDS_IPAQ_MICRO)		+= leds-ipaq-micro.o
+obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
 obj-$(CONFIG_LEDS_HP6XX)		+= leds-hp6xx.o
 obj-$(CONFIG_LEDS_OT200)		+= leds-ot200.o
 obj-$(CONFIG_LEDS_FSG)			+= leds-fsg.o
diff --git a/drivers/leds/leds-is31fl319x.c b/drivers/leds/leds-is31fl319x.c
new file mode 100644
index 0000000..e211c46
--- /dev/null
+++ b/drivers/leds/leds-is31fl319x.c
@@ -0,0 +1,406 @@
+/*
+ * Copyright 2015 Golden Delcious Computers
+ *
+ * Author: Nikolaus Schaller <hns@...delico.com>
+ *
+ * Based on leds-tca6507.c
+ *
+ * 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.
+ *
+ * LED driver for the IS31FL3196/99 to drive 6 or 9 light effect LEDs.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/workqueue.h>
+#include <linux/leds-is31fl319x.h>
+#include <linux/of.h>
+
+/* register numbers */
+#define IS31FL319X_SHUTDOWN	0x00
+#define IS31FL319X_CTRL1	0x01
+#define IS31FL319X_CTRL2	0x02
+#define IS31FL319X_CONFIG1	0x03
+#define IS31FL319X_CONFIG2	0x04
+#define IS31FL319X_RAMP_MODE	0x05
+#define IS31FL319X_BREATH_MASK	0x06
+#define IS31FL319X_PWM1		0x07
+#define IS31FL319X_PWM2		0x08
+#define IS31FL319X_PWM3		0x09
+#define IS31FL319X_PWM4		0x0a
+#define IS31FL319X_PWM5		0x0b
+#define IS31FL319X_PWM6		0x0c
+#define IS31FL319X_PWM7		0x0d
+#define IS31FL319X_PWM8		0x0e
+#define IS31FL319X_PWM9		0x0f
+#define IS31FL319X_DATA_UPDATE	0x10
+#define IS31FL319X_T0_1		0x11
+#define IS31FL319X_T0_2		0x12
+#define IS31FL319X_T0_3		0x13
+#define IS31FL319X_T0_4		0x14
+#define IS31FL319X_T0_5		0x15
+#define IS31FL319X_T0_6		0x16
+#define IS31FL319X_T0_7		0x17
+#define IS31FL319X_T0_8		0x18
+#define IS31FL319X_T0_9		0x19
+#define IS31FL319X_T123_1	0x1a
+#define IS31FL319X_T123_2	0x1b
+#define IS31FL319X_T123_3	0x1c
+#define IS31FL319X_T4_1		0x1d
+#define IS31FL319X_T4_2		0x1e
+#define IS31FL319X_T4_3		0x1f
+#define IS31FL319X_T4_4		0x20
+#define IS31FL319X_T4_5		0x21
+#define IS31FL319X_T4_6		0x22
+#define IS31FL319X_T4_7		0x23
+#define IS31FL319X_T4_8		0x24
+#define IS31FL319X_T4_9		0x25
+#define IS31FL319X_TIME_UPDATE	0x26
+
+#define	IS31FL319X_REG_CNT	(IS31FL319X_TIME_UPDATE + 1)
+
+#define NUM_LEDS 9	/* max for 3199 chip */
+
+struct is31fl319x_chip {
+	struct i2c_client	*client;
+	struct work_struct	work;
+	bool			work_scheduled;
+	spinlock_t		lock;
+	u8			reg_file[IS31FL319X_REG_CNT];
+
+	struct is31fl319x_led {
+		struct is31fl319x_chip	*chip;
+		struct led_classdev	led_cdev;
+	} leds[NUM_LEDS];
+};
+
+static const struct i2c_device_id is31fl319x_id[] = {
+	{ "is31fl3196", 6 },
+	{ "is31fl3196", 9 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
+
+
+static int is31fl319x_write(struct is31fl319x_chip *is31, u8 reg, u8 byte)
+{
+	struct i2c_client *cl = is31->client;
+
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	is31->reg_file[reg] = byte;	/* save in cache */
+	dev_dbg(&is31->client->dev, "write %02x to reg %02x\n", byte, reg);
+	return i2c_smbus_write_byte_data(cl, reg, byte);
+}
+
+static int is31fl319x_read(struct is31fl319x_chip *is31, u8 reg)
+{
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	return is31->reg_file[reg];	/* read crom cache (can't read chip) */
+}
+
+static void is31fl319x_work(struct work_struct *work)
+{
+	struct is31fl319x_chip *is31 = container_of(work,
+						    struct is31fl319x_chip,
+						    work);
+	unsigned long flags;
+	int i;
+	u8 ctrl1, ctrl2;
+
+	dev_dbg(&is31->client->dev, "work called\n");
+
+	spin_lock_irqsave(&is31->lock, flags);
+	/* make subsequent changes run another schedule_work */
+	is31->work_scheduled = false;
+	spin_unlock_irqrestore(&is31->lock, flags);
+
+	dev_dbg(&is31->client->dev, "write to chip\n");
+
+	ctrl1 = 0;
+	ctrl2 = 0;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct led_classdev *led = &is31->leds[i].led_cdev;
+		bool on;
+
+		if (!is31->leds[i].led_cdev.name)
+			continue;
+
+		dev_dbg(&is31->client->dev, "set brightness %u for led %u\n",
+					    led->brightness, i);
+
+		/* update brightness register */
+		is31fl319x_write(is31, IS31FL319X_PWM1 + i, led->brightness);
+
+		/* update output enable bits */
+		on = led->brightness > LED_OFF;
+		if (i < 3)
+			ctrl1 |= on << i;	/* 0..2 => bit 0..2 */
+		else if (i < 6)
+			ctrl1 |= on << (i+1);	/* 3..5 => bit 4..6 */
+		else
+			ctrl2 |= on << (i-6);	/* 6..8 => bit 0..2 */
+	}
+
+	/* check if any PWM is enabled or all outputs are now off */
+	if (ctrl1 > 0 || ctrl2 > 0) {
+		dev_dbg(&is31->client->dev, "power up\n");
+		is31fl319x_write(is31, IS31FL319X_CTRL1, ctrl1);
+		is31fl319x_write(is31, IS31FL319X_CTRL2, ctrl2);
+		/* update PWMs */
+		is31fl319x_write(is31, IS31FL319X_DATA_UPDATE, 0x00);
+		/* enable chip from shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	} else {
+		dev_dbg(&is31->client->dev, "power down\n");
+		/* shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x00);
+	}
+
+	dev_dbg(&is31->client->dev, "work done\n");
+
+}
+
+/* NOTE: this may be called from within irq context, e.g. led_trigger_event */
+
+static int is31fl319x_brightness_get(struct led_classdev *led_cdev)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+
+	/* read PWM register */
+	return is31fl319x_read(is31, IS31FL319X_PWM1 + (led - is31->leds));
+}
+
+static void is31fl319x_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness brightness)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+	unsigned long flags;
+
+	spin_lock_irqsave(&is31->lock, flags);
+
+	if (brightness != is31fl319x_brightness_get(led_cdev)) {
+		if (!is31->work_scheduled) {
+			schedule_work(&is31->work);
+			is31->work_scheduled = true;
+		}
+	}
+
+	spin_unlock_irqrestore(&is31->lock, flags);
+}
+
+static int is31fl319x_blink_set(struct led_classdev *led_cdev,
+			     unsigned long *delay_on,
+			     unsigned long *delay_off)
+{
+	/* use software blink */
+	return 1;
+}
+
+#ifdef CONFIG_OF
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client, int num_leds)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct is31fl319x_platform_data *pdata;
+	struct led_info *is31_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	dev_dbg(&client->dev, "child count %d\n", count);
+	if (!count || count > NUM_LEDS)
+		return ERR_PTR(-ENODEV);
+
+	is31_leds = devm_kzalloc(&client->dev,
+			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!is31_leds)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_child_of_node(np, child) {
+		struct led_info led;
+		u32 reg;
+		int ret;
+
+		led.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);
+		led.flags = 0;
+		ret = of_property_read_u32(child, "reg", &reg);
+		dev_dbg(&client->dev, "name = %s reg = %d\n", led.name, reg);
+		if (ret != 0 || reg < 0 || reg >= num_leds)
+			continue;
+
+		if (is31_leds[reg].name)
+			dev_err(&client->dev, "duplicate led line %d for %s -> %s\n",
+				reg, is31_leds[reg].name, led.name);
+		is31_leds[reg] = led;
+	}
+	pdata = devm_kzalloc(&client->dev,
+			sizeof(struct is31fl319x_platform_data), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds.leds = is31_leds;
+	return pdata;
+}
+
+static const struct of_device_id of_is31fl319x_leds_match[] = {
+	{ .compatible = "issi,is31fl3196", (void *) 6 },
+	{ .compatible = "issi,is31fl3199", (void *) 9 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_is31fl319x_leds_match);
+
+#else
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	struct is31fl319x_platform_data *pdata;
+	int err;
+	int i = 0;
+
+	adapter = to_i2c_adapter(client->dev.parent);
+	pdata = dev_get_platdata(&client->dev);
+
+	dev_dbg(&client->dev, "probe\n");
+
+	dev_dbg(&client->dev, "NUM_LEDS = %d num_leds = %d\n",
+		NUM_LEDS, (int) id->driver_data);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+		return -EIO;
+
+	if (!pdata) {
+		pdata = is31fl319x_led_dt_init(client, (int) id->driver_data);
+		if (IS_ERR(pdata)) {
+			dev_err(&client->dev, "DT led error %d\n",
+				(int) PTR_ERR(pdata));
+			return PTR_ERR(pdata);
+		}
+	}
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	is31->client = client;
+	INIT_WORK(&is31->work, is31fl319x_work);
+	spin_lock_init(&is31->lock);
+	i2c_set_clientdata(client, is31);
+
+	/* check for reply from chip (we can't read any registers) */
+	err = is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	if (err < 0) {
+		dev_err(&client->dev, "no response from chip write: err = %d\n",
+			err);
+		return -EPROBE_DEFER;	/* does not answer (yet) */
+	}
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct is31fl319x_led *l = is31->leds + i;
+
+		l->chip = is31;
+		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
+			l->led_cdev.name = pdata->leds.leds[i].name;
+			l->led_cdev.default_trigger
+				= pdata->leds.leds[i].default_trigger;
+			l->led_cdev.brightness_set = is31fl319x_brightness_set;
+			l->led_cdev.blink_set = is31fl319x_blink_set;
+			err = led_classdev_register(&client->dev,
+						    &l->led_cdev);
+			if (err < 0)
+				goto exit;
+		}
+	}
+
+	if (client->dev.of_node) {
+		u32 val;
+		u8 config2 = 0;
+
+		if (of_property_read_u32(client->dev.of_node, "max-current-ma",
+					 &val)) {
+			if (val > 40)
+				val = 40;
+			if (val < 5)
+				val = 5;
+			config2 |= (((64 - val) / 5) & 0x7) << 4; /* CS */
+		}
+		if (of_property_read_u32(client->dev.of_node, "audio-gain-db",
+					 &val)) {
+			if (val > 21)
+				val = 21;
+			config2 |= val / 3; /* AGS */
+		}
+		if (config2)
+			is31fl319x_write(is31, IS31FL319X_CONFIG2, config2);
+	}
+
+	schedule_work(&is31->work);	/* first update */
+
+	dev_dbg(&client->dev, "probed\n");
+	return 0;
+exit:
+	dev_err(&client->dev, "led error %d\n", err);
+
+	while (i--) {
+		if (is31->leds[i].led_cdev.name)
+			led_classdev_unregister(&is31->leds[i].led_cdev);
+	}
+	return err;
+}
+
+static int is31fl319x_remove(struct i2c_client *client)
+{
+	int i;
+	struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
+	struct is31fl319x_led *is31_leds = is31->leds;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		if (is31_leds[i].led_cdev.name)
+			led_classdev_unregister(&is31_leds[i].led_cdev);
+	}
+
+	cancel_work_sync(&is31->work);
+
+	return 0;
+}
+
+static struct i2c_driver is31fl319x_driver = {
+	.driver   = {
+		.name    = "leds-is31fl319x",
+		.of_match_table = of_match_ptr(of_is31fl319x_leds_match),
+	},
+	.probe    = is31fl319x_probe,
+	.remove   = is31fl319x_remove,
+	.id_table = is31fl319x_id,
+};
+
+module_i2c_driver(is31fl319x_driver);
+
+MODULE_AUTHOR("H. Nikolaus Schaller <hns@...delico.com>");
+MODULE_DESCRIPTION("IS31FL319X LED driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/leds-is31fl319x.h b/include/linux/leds-is31fl319x.h
new file mode 100644
index 0000000..5f55abf
--- /dev/null
+++ b/include/linux/leds-is31fl319x.h
@@ -0,0 +1,24 @@
+/*
+ * IS31FL3196 LED chip driver.
+ *
+ * Copyright (C) 2015 H. Nikolaus Schaller <hns@...delico.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __LINUX_IS31FL319X_H
+#define __LINUX_IS31FL319X_H
+#include <linux/leds.h>
+
+struct is31fl319x_platform_data {
+	struct led_platform_data leds;
+};
+
+#endif /* __LINUX_IS31FL319X_H */
-- 
2.7.3

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