Date:	Fri,  8 Jul 2016 21:49:37 +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,
	Andrey Utkin <andrey_utkin@...tmail.com>
Subject: [PATCH v3 1/2] drivers: led: is31fl319x: 1/3/6/9-channel light effect led driver

This is a driver for the Integrated Silicon Solution Inc. LED driver
chips series IS31FL319x. They can drive 1, 3, 6  or up to 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
in the range 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 fully
supported by this driver.

Tested-on: OMAP5 based Pyra handheld prototype.
Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
Signed-off-by: Andrey Utkin <andrey_utkin@...tmail.com>
---
 drivers/leds/Kconfig           |  12 ++
 drivers/leds/Makefile          |   1 +
 drivers/leds/leds-is31fl319x.c | 405 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 418 insertions(+)
 create mode 100644 drivers/leds/leds-is31fl319x.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 5ae2834..6439a7d 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -570,6 +570,18 @@ config LEDS_SEAD3
 	  This driver can also be built as a module. If so the module
 	  will be called leds-sead3.
 
+config LEDS_IS31FL319X
+	tristate "LED Support for ISSI IS31FL319x I2C LED controller family"
+	depends on LEDS_CLASS && I2C && OF
+	select REGMAP_I2C
+	help
+	  This option enables support for LEDs connected to ISSI IS31FL319x
+	  fancy LED driver chips accessed via the I2C bus.
+	  Driver supports individual PWM brightness control for each channel.
+
+	  This driver can also be built as a module. If so the module will be
+	  called leds-is31fl319x.
+
 config LEDS_IS31FL32XX
 	tristate "LED support for ISSI IS31FL32XX I2C LED controller family"
 	depends on LEDS_CLASS && I2C && OF
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index cb2013d..b6ce9f9 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -66,6 +66,7 @@ obj-$(CONFIG_LEDS_MENF21BMC)		+= leds-menf21bmc.o
 obj-$(CONFIG_LEDS_KTD2692)		+= leds-ktd2692.o
 obj-$(CONFIG_LEDS_POWERNV)		+= leds-powernv.o
 obj-$(CONFIG_LEDS_SEAD3)		+= leds-sead3.o
+obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
 obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
 
 # LED SPI Drivers
diff --git a/drivers/leds/leds-is31fl319x.c b/drivers/leds/leds-is31fl319x.c
new file mode 100644
index 0000000..7fc5c6ab
--- /dev/null
+++ b/drivers/leds/leds-is31fl319x.c
@@ -0,0 +1,405 @@
+/*
+ * Copyright 2015-16 Golden Delicious 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 IS31FL319{0,1,3,6,9} to drive 1, 3, 6 or 9 light
+ * effect LEDs.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.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_PWM(channel) (0x07 + channel)
+#define IS31FL319X_DATA_UPDATE  0x10
+#define IS31FL319X_T0(channel)  (0x11 + channel)
+#define IS31FL319X_T123_1       0x1a
+#define IS31FL319X_T123_2       0x1b
+#define IS31FL319X_T123_3       0x1c
+#define IS31FL319X_T4(channel)  (0x1d + channel)
+#define IS31FL319X_TIME_UPDATE  0x26
+#define IS31FL319X_RESET        0xff
+
+#define IS31FL319X_REG_CNT      (IS31FL319X_RESET + 1)
+
+#define NUM_LEDS 9 /* max for 3199 chip */
+
+#define LED_MAX_MICROAMP_UPPER_LIMIT ((u32) 40000)
+#define LED_MAX_MICROAMP_LOWER_LIMIT ((u32) 5000)
+#define LED_MAX_MICROAMP_DEFAULT ((u32) 20000)
+#define LED_MAX_MICROAMP_STEP ((u32) 5000)
+
+#define AUDIO_GAIN_DB_MAX ((u32) 21)
+
+/*
+ * regmap is used as a cache of chip's register space,
+ * to avoid reading back brightness values from chip,
+ * which is known to hang.
+ */
+struct is31fl319x_chip {
+	struct i2c_client       *client;
+	struct regmap           *regmap;
+	struct mutex            lock;
+	u32                     audio_gain_db;
+
+	struct is31fl319x_led {
+		struct is31fl319x_chip  *chip;
+		struct led_classdev     cdev;
+		u32                     max_microamp;
+		bool                    configured;
+	} leds[NUM_LEDS];
+};
+
+static const struct i2c_device_id is31fl319x_id[] = {
+	{ "is31fl3190", 1 },
+	{ "is31fl3191", 1 },
+	{ "is31fl3193", 3 },
+	{ "is31fl3196", 6 },
+	{ "is31fl3199", 9 },
+	{ "sn3199", 9 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
+
+static int is31fl319x_brightness_set(struct led_classdev *cdev,
+				   enum led_brightness brightness)
+{
+	struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led,
+						  cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+	int chan = led - is31->leds;
+	int ret;
+	int i;
+	u8 ctrl1 = 0, ctrl2 = 0;
+
+	dev_dbg(&is31->client->dev, "%s %d: %d\n", __func__, chan, brightness);
+
+	mutex_lock(&is31->lock);
+
+	/* update PWM register */
+	ret = regmap_write(is31->regmap, IS31FL319X_PWM(chan), brightness);
+	if (ret < 0)
+		goto out;
+
+	/* read current brightness of all PWM channels */
+	for (i = 0; i < NUM_LEDS; i++) {
+		unsigned int pwm_value;
+		bool on;
+
+		/*
+		 * since neither cdev nor the chip can provide
+		 * the current setting, we read from the regmap cache
+		 */
+
+		ret = regmap_read(is31->regmap, IS31FL319X_PWM(i), &pwm_value);
+		dev_dbg(&is31->client->dev, "%s read %d: ret=%d: %d\n",
+			__func__, i, ret, pwm_value);
+		on = ret >= 0 && pwm_value > 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 */
+	}
+
+	if (ctrl1 > 0 || ctrl2 > 0) {
+		dev_dbg(&is31->client->dev, "power up %02x %02x\n",
+			ctrl1, ctrl2);
+		regmap_write(is31->regmap, IS31FL319X_CTRL1, ctrl1);
+		regmap_write(is31->regmap, IS31FL319X_CTRL2, ctrl2);
+		/* update PWMs */
+		regmap_write(is31->regmap, IS31FL319X_DATA_UPDATE, 0x00);
+		/* enable chip from shut down */
+		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
+	} else {
+		dev_dbg(&is31->client->dev, "power down\n");
+		/* shut down (no need to clear CTRL1/2) */
+		ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
+	}
+
+out:
+	mutex_unlock(&is31->lock);
+
+	return ret;
+}
+
+static int is31fl319x_parse_child_dt(const struct device *dev,
+				     const struct device_node *child,
+				     struct is31fl319x_led *led)
+{
+	struct led_classdev *cdev = &led->cdev;
+	int ret;
+
+	if (of_property_read_string(child, "label", &cdev->name))
+		cdev->name = child->name;
+
+	cdev->default_trigger = NULL;
+	ret = of_property_read_string(child, "linux,default-trigger",
+		&cdev->default_trigger);
+	if (ret < 0 && ret != -EINVAL) /* is optional */
+		return ret;
+
+	led->max_microamp = LED_MAX_MICROAMP_DEFAULT;
+	ret = of_property_read_u32(child, "led-max-microamp",
+				   &led->max_microamp);
+	if (!ret) {
+		led->max_microamp = clamp(led->max_microamp,
+					  LED_MAX_MICROAMP_LOWER_LIMIT,
+					  LED_MAX_MICROAMP_UPPER_LIMIT);
+		led->max_microamp -= led->max_microamp % LED_MAX_MICROAMP_STEP;
+	}
+
+	return 0;
+}
+
+static int is31fl319x_parse_dt(struct device *dev,
+			       struct is31fl319x_chip *is31)
+{
+	struct device_node *np = dev->of_node, *child;
+	struct led_info *is31_leds;
+	int count;
+	int ret;
+
+	if (!np)
+		return -ENODEV;
+
+	count = of_get_child_count(np);
+
+	dev_dbg(dev, "child count %d\n", count);
+	if (!count || count > NUM_LEDS)
+		return -ENODEV;
+
+	is31_leds = devm_kzalloc(dev, sizeof(struct led_info) * NUM_LEDS,
+				 GFP_KERNEL);
+	if (!is31_leds)
+		return -ENOMEM;
+
+	for_each_child_of_node(np, child) {
+		struct is31fl319x_led *led;
+		u32 reg;
+
+		ret = of_property_read_u32(child, "reg", &reg);
+		if (ret)
+			break;
+
+		if (reg < 1 || reg > NUM_LEDS) {
+			dev_err(dev, "invalid led reg %u\n", reg);
+			ret = -EINVAL;
+			break;
+		}
+
+		led = &is31->leds[reg - 1];
+
+		if (led->configured) {
+			dev_err(dev, "led %u is already configured\n", reg);
+			ret = -EINVAL;
+			break;
+		}
+
+		ret = is31fl319x_parse_child_dt(dev, child, led);
+		if (ret) {
+			dev_err(dev, "led %u DT parsing failed\n", reg);
+			break;
+		}
+
+		led->configured = true;
+	}
+	if (ret) {
+		dev_err(dev, "DT child nodes parsing failed, error %d\n", ret);
+		return ret;
+	}
+
+	is31->audio_gain_db = 0;
+	ret = of_property_read_u32(np, "audio-gain-db", &is31->audio_gain_db);
+	if (!ret) {
+		is31->audio_gain_db = min(is31->audio_gain_db,
+					  AUDIO_GAIN_DB_MAX);
+		is31->audio_gain_db -= is31->audio_gain_db % 3;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id of_is31fl319x_leds_match[] = {
+	{ .compatible = "issi,is31fl3190", (void *) 1 },
+	{ .compatible = "issi,is31fl3191", (void *) 1 },
+	{ .compatible = "issi,is31fl3193", (void *) 3 },
+	{ .compatible = "issi,is31fl3196", (void *) 6 },
+	{ .compatible = "issi,is31fl3199", (void *) 9 },
+	{ .compatible = "si-en,sn3199", (void *) 9 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_is31fl319x_leds_match);
+
+static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
+{ /* we have no readable registers */
+	return false;
+}
+
+static bool is31fl319x_volatile_reg(struct device *dev, unsigned int reg)
+{ /* volatile registers are not cached */
+	switch (reg) {
+	case IS31FL319X_DATA_UPDATE:
+	case IS31FL319X_TIME_UPDATE:
+	case IS31FL319X_RESET:
+		return true; /* always write-through */
+	default:
+		return false;
+	}
+}
+
+static const struct reg_default is31fl319x_reg_defaults[] = {
+	{ IS31FL319X_CONFIG1, 0x00},
+	{ IS31FL319X_CONFIG2, 0x00},
+	{ IS31FL319X_PWM(0), 0x00},
+	{ IS31FL319X_PWM(1), 0x00},
+	{ IS31FL319X_PWM(2), 0x00},
+	{ IS31FL319X_PWM(3), 0x00},
+	{ IS31FL319X_PWM(4), 0x00},
+	{ IS31FL319X_PWM(5), 0x00},
+	{ IS31FL319X_PWM(6), 0x00},
+	{ IS31FL319X_PWM(7), 0x00},
+	{ IS31FL319X_PWM(8), 0x00},
+};
+
+static struct regmap_config regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = IS31FL319X_REG_CNT,
+	.cache_type = REGCACHE_FLAT,
+	.readable_reg = is31fl319x_readable_reg,
+	.volatile_reg = is31fl319x_volatile_reg,
+	.reg_defaults = is31fl319x_reg_defaults,
+	.num_reg_defaults = ARRAY_SIZE(is31fl319x_reg_defaults),
+};
+
+static int is31fl319x_microamp_to_cs(u32 microamp)
+{
+	switch (microamp) {
+	default:
+		WARN(1, "Invalid microamp setting");
+	case 20000: return 0;
+	case 15000: return 1;
+	case 10000: return 2;
+	case 5000:  return 3;
+	case 40000: return 4;
+	case 35000: return 5;
+	case 30000: return 6;
+	case 25000: return 7;
+	}
+}
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	int err;
+	int i = 0;
+	u32 aggregated_led_microamp = LED_MAX_MICROAMP_UPPER_LIMIT;
+
+	adapter = to_i2c_adapter(client->dev.parent);
+
+	dev_dbg(&client->dev, "probe IS31FL319x for num_leds = %d\n",
+		(int) id->driver_data);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+		return -EIO;
+
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	mutex_init(&is31->lock);
+
+	err = is31fl319x_parse_dt(&client->dev, is31);
+	if (err) {
+		dev_err(&client->dev, "DT parsing error %d\n", err);
+		return err;
+	}
+
+	is31->client = client;
+	is31->regmap = devm_regmap_init_i2c(client, &regmap_config);
+	if (IS_ERR(is31->regmap)) {
+		dev_err(&client->dev, "failed to allocate register map\n");
+		return PTR_ERR(is31->regmap);
+	}
+
+	i2c_set_clientdata(client, is31);
+
+	/* check for write-reply from chip (we can't read any registers) */
+	err = regmap_write(is31->regmap, IS31FL319X_RESET, 0x00);
+	if (err < 0) {
+		dev_err(&client->dev, "no response from chip write: err = %d\n",
+			err);
+		return -EIO; /* does not answer */
+	}
+
+	/*
+	 * Kernel conventions require per-LED led-max-microamp property.
+	 * But the chip does not allow to limit individual LEDs.
+	 * So we take minimum from all subnodes.
+	 */
+	for (i = 0; i < NUM_LEDS; i++)
+		if (is31->leds[i].configured &&
+		    is31->leds[i].max_microamp < aggregated_led_microamp)
+			aggregated_led_microamp = is31->leds[i].max_microamp;
+
+	regmap_write(is31->regmap, IS31FL319X_CONFIG2,
+		     is31fl319x_microamp_to_cs(aggregated_led_microamp) << 4 |
+		     is31->audio_gain_db / 3);
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct is31fl319x_led *led = &is31->leds[i];
+
+		if (!led->configured)
+			continue;
+
+		led->chip = is31;
+		led->cdev.brightness_set_blocking = is31fl319x_brightness_set;
+
+		err = devm_led_classdev_register(&client->dev, &led->cdev);
+		if (err < 0)
+			return err;
+	}
+
+	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,
+	.id_table = is31fl319x_id,
+};
+
+module_i2c_driver(is31fl319x_driver);
+
+MODULE_AUTHOR("H. Nikolaus Schaller <hns@...delico.com>");
+MODULE_AUTHOR("Andrey Utkin <andrey_utkin@...tmail.com>");
+MODULE_DESCRIPTION("IS31FL319X LED driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.3

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