Message-Id: <089f8597f3424ac64a6b6283d9fa0eb15b29e8c8.1467799364.git.hns@goldelico.com>
Date:	Wed,  6 Jul 2016 12:02:43 +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 v2 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>
---
 drivers/leds/Kconfig           |   8 +
 drivers/leds/Makefile          |   1 +
 drivers/leds/leds-is31fl319x.c | 354 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 363 insertions(+)
 create mode 100644 drivers/leds/leds-is31fl319x.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 5ae2834..65b1045 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -570,6 +570,14 @@ 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
+	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.
+
 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..bbf8850
--- /dev/null
+++ b/drivers/leds/leds-is31fl319x.c
@@ -0,0 +1,354 @@
+/*
+ * 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 IS31FL3191/3/6/99 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_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_RESET	0xff
+
+#define IS31FL319X_REG_CNT	(IS31FL319X_RESET + 1)
+
+#define NUM_LEDS 9	/* max for 3199 chip */
+
+struct is31fl319x_chip {
+	struct i2c_client	*client;
+	struct regmap		*regmap;
+
+	struct is31fl319x_led {
+		struct is31fl319x_chip	*chip;
+		struct led_classdev	led_cdev;
+	} 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 *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;
+	int ret;
+
+	int i;
+	u8 ctrl1, ctrl2;
+
+	dev_dbg(&is31->client->dev, "%s %d: %d\n", __func__, (led - is31->leds),
+		brightness);
+
+	/* update PWM register */
+	ret = regmap_write(is31->regmap, IS31FL319X_PWM1 + (led - is31->leds),
+			   brightness);
+	if (ret < 0)
+		return ret;
+
+	ctrl1 = 0;
+	ctrl2 = 0;
+
+	/* read current brightness of all PWM channels */
+	for (i = 0; i < NUM_LEDS; i++) {
+		unsigned int pwm_value;
+		bool on;
+
+		/*
+		 * since neither led_cdev nor the chip can provide
+		 * the current setting, we read from the regmap cache
+		 */
+
+		ret = regmap_read(is31->regmap, IS31FL319X_PWM1 + 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);
+	}
+
+	return ret;
+}
+
+static struct led_info *
+is31fl319x_parse_dt(struct i2c_client *client, int num_leds)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct led_info *is31_leds;
+	int count;
+
+	if (!np)
+		return ERR_PTR(-ENODEV);
+
+	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 = NULL;
+		ret = of_property_read_string(child, "label", &led.name);
+		if (ret < 0 && ret != -EINVAL)	/* is optional */
+			return ERR_PTR(ret);
+		led.default_trigger = NULL;
+		ret = of_property_read_string(child, "linux,default-trigger",
+			&led.default_trigger);
+		if (ret < 0 && ret != -EINVAL)	/* is optional */
+			return ERR_PTR(ret);
+		led.flags = 0;
+		ret = of_property_read_u32(child, "reg", &reg);
+		dev_dbg(&client->dev, "name = %s reg = %d\n", led.name, reg);
+		reg -= 1;	/* index 0 is at reg = 1 */
+		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;
+	}
+
+	return is31_leds;
+}
+
+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;
+	}
+}
+
+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,
+};
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	struct led_info *leds;
+	int err;
+	int i = 0;
+
+	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;
+
+	leds = is31fl319x_parse_dt(client, (int) id->driver_data);
+	if (IS_ERR(leds)) {
+		dev_err(&client->dev, "DT parsing error %d\n",
+			(int) PTR_ERR(leds));
+		return PTR_ERR(leds);
+	}
+
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	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 */
+	}
+
+	/* initialize chip and regmap so that we never try to read from i2c */
+	regmap_write(is31->regmap, IS31FL319X_CTRL1, 0x00);
+	regmap_write(is31->regmap, IS31FL319X_CTRL2, 0x00);
+	for (i = 0; i < NUM_LEDS; i++)
+		regmap_write(is31->regmap, IS31FL319X_PWM1 + i, 0x00);
+
+	if (client->dev.of_node) {
+		u32 val;
+		u8 config2 = 0;
+
+		if (of_property_read_u32(client->dev.of_node,
+					 "led-max-microamp", &val)) {
+			if (val > 40000)
+				val = 40000;
+			if (val < 5000)
+				val = 5000;
+			config2 |= (((64000 - val) / 5000) & 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 */
+		}
+		regmap_write(is31->regmap, IS31FL319X_CONFIG2, config2);
+	}
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct is31fl319x_led *l = is31->leds + i;
+
+		l->chip = is31;
+		if (leds[i].name && !leds[i].flags) {
+			l->led_cdev.name = leds[i].name;
+			l->led_cdev.default_trigger
+				= leds[i].default_trigger;
+			l->led_cdev.brightness_set_blocking
+				= is31fl319x_brightness_set;
+			/* NOTE: is31fl319x_brightness_set will be called
+			 * immediately after register() before we return
+			 */
+			err = devm_led_classdev_register(&client->dev,
+						    &l->led_cdev);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	dev_dbg(&client->dev, "probed\n");
+	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_DESCRIPTION("IS31FL319X LED driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.3

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