Re: [PATCH v7 1/1] leds: LED driver for TI LP3952 6-Channel Color LED

[Jacek Anaszewski <j.anaszewski@samsung.com>]

Hi Rafael,

On 06/29/2016 02:45 AM, Rafael J. Wysocki wrote:
> On Tuesday, June 28, 2016 05:05:19 PM Tony Makkiel wrote:
>> The chip can drive 2 sets of RGB leds. Controller can
>> be controlled via PWM, I2C and audio synchronisation.
>> This driver uses I2C to communicate with the chip.
>>
>> Datasheet: http://www.ti.com/lit/gpn/lp3952
>>
>> Signed-off-by: Tony Makkiel <tony.makkiel@daqri.com>
>> ---
>>   drivers/leds/Kconfig        |  13 ++
>>   drivers/leds/Makefile       |   1 +
>>   drivers/leds/leds-lp3952.c  | 289 ++++++++++++++++++++++++++++++++++++++++++++
>>   include/linux/leds-lp3952.h | 128 ++++++++++++++++++++
>>   4 files changed, 431 insertions(+)
>>   create mode 100644 drivers/leds/leds-lp3952.c
>>   create mode 100644 include/linux/leds-lp3952.h
>>
>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
>> index 5ae2834..0f321f4 100644
>> --- a/drivers/leds/Kconfig
>> +++ b/drivers/leds/Kconfig
>> @@ -228,6 +228,19 @@ config LEDS_LP3944
>>   	  To compile this driver as a module, choose M here: the
>>   	  module will be called leds-lp3944.
>>
>> +config LEDS_LP3952
>> +	tristate "LED Support for TI LP3952 2 channel LED driver"
>> +	depends on LEDS_CLASS
>> +	depends on I2C
>> +	depends on ACPI
>> +	select REGMAP_I2C
>> +	help
>> +	  This option enables support for LEDs connected to the Texas
>> +	  Instruments LP3952 LED driver.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called leds-lp3952.
>> +
>>   config LEDS_LP55XX_COMMON
>>   	tristate "Common Driver for TI/National LP5521/5523/55231/5562/8501"
>>   	depends on LEDS_LP5521 || LEDS_LP5523 || LEDS_LP5562 || LEDS_LP8501
>> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
>> index cb2013d..0684c86 100644
>> --- a/drivers/leds/Makefile
>> +++ b/drivers/leds/Makefile
>> @@ -26,6 +26,7 @@ obj-$(CONFIG_LEDS_PCA9532)		+= leds-pca9532.o
>>   obj-$(CONFIG_LEDS_GPIO_REGISTER)	+= leds-gpio-register.o
>>   obj-$(CONFIG_LEDS_GPIO)			+= leds-gpio.o
>>   obj-$(CONFIG_LEDS_LP3944)		+= leds-lp3944.o
>> +obj-$(CONFIG_LEDS_LP3952)		+= leds-lp3952.o
>>   obj-$(CONFIG_LEDS_LP55XX_COMMON)	+= leds-lp55xx-common.o
>>   obj-$(CONFIG_LEDS_LP5521)		+= leds-lp5521.o
>>   obj-$(CONFIG_LEDS_LP5523)		+= leds-lp5523.o
>> diff --git a/drivers/leds/leds-lp3952.c b/drivers/leds/leds-lp3952.c
>> new file mode 100644
>> index 0000000..cec7374
>> --- /dev/null
>> +++ b/drivers/leds/leds-lp3952.c
>> @@ -0,0 +1,289 @@
>> +/*
>> + *	LED driver for TI lp3952 controller
>> + *
>> + *	Copyright (C) 2016, DAQRI, LLC.
>> + *	Author: Tony Makkiel <tony.makkiel@daqri.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.
>> + *
>> + */
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/delay.h>
>> +#include <linux/gpio.h>
>> +#include <linux/i2c.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/leds.h>
>> +#include <linux/leds-lp3952.h>
>> +#include <linux/module.h>
>> +#include <linux/notifier.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm.h>
>> +#include <linux/reboot.h>
>> +#include <linux/regmap.h>
>> +
>> +static int lp3952_register_write(struct i2c_client *client, u8 reg, u8 val)
>> +{
>> +	int ret;
>> +	struct lp3952_led_array *priv = i2c_get_clientdata(client);
>> +
>> +	ret = regmap_write(priv->regmap, reg, val);
>> +
>> +	if (ret)
>> +		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
>> +			__func__, reg, val, ret);
>> +	return ret;
>> +}
>> +
>> +static void lp3952_on_off(struct lp3952_led_array *priv,
>> +			  enum lp3952_leds led_id, int on)
>> +{
>> +	int ret, val;
>> +
>> +	dev_dbg(&priv->client->dev, "%s LED %d to %d\n", __func__, led_id, on);
>> +
>> +	val = 1 << led_id;
>> +	if (led_id == LP3952_LED_ALL)
>> +		val = LP3952_LED_MASK_ALL;
>> +
>> +	ret = regmap_update_bits(priv->regmap, LP3952_REG_LED_CTRL, val,
>> +				 on ? val : 0);
>> +	if (ret)
>> +		dev_err(&priv->client->dev, "%s, Error %d\n", __func__, ret);
>> +}
>> +
>> +/*
>> + * Using Imax to control brightness. There are 4 possible
>> + * setting 25, 50, 75 and 100 % of Imax. Possible values are
>> + * values 0-4. 0 meaning turn off.
>> + */
>> +static int lp3952_set_brightness(struct led_classdev *cdev,
>> +				 enum led_brightness value)
>> +{
>> +	unsigned int reg, shift_val;
>> +	struct lp3952_ctrl_hdl *led = container_of(cdev,
>> +						   struct lp3952_ctrl_hdl,
>> +						   cdev);
>> +	struct lp3952_led_array *priv = (struct lp3952_led_array *)led->priv;
>> +
>> +	dev_dbg(cdev->dev, "Brightness request: %d on %d\n", value,
>> +		led->channel);
>> +
>> +	if (value == LED_OFF) {
>> +		lp3952_on_off(priv, led->channel, LED_OFF);
>> +		return 0;
>> +	}
>> +
>> +	if (led->channel > LP3952_RED_1) {
>> +		dev_err(cdev->dev, " %s Invalid LED requested", __func__);
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (led->channel >= LP3952_BLUE_1) {
>> +		reg = LP3952_REG_RGB1_MAX_I_CTRL;
>> +		shift_val = (led->channel - LP3952_BLUE_1) * 2;
>> +	} else {
>> +		reg = LP3952_REG_RGB2_MAX_I_CTRL;
>> +		shift_val = led->channel * 2;
>> +	}
>> +
>> +	/* Enable the LED in case it is not enabled already */
>> +	lp3952_on_off(priv, led->channel, 1);
>> +
>> +	return regmap_update_bits(priv->regmap, reg, 3 << shift_val,
>> +				  --value << shift_val);
>> +}
>> +
>> +static int lp3952_register_led_classdev(struct lp3952_led_array *priv)
>> +{
>> +	int i, ret = -ENODEV;
>> +	static const char *led_name[LP3952_LED_ALL] = {
>> +		"lp3952:blue2",
>> +		"lp3952:green2",
>> +		"lp3952:red2",
>> +		"lp3952:blue1",
>> +		"lp3952:green1",
>> +		"lp3952:red1"
>> +	};
>> +
>> +	for (i = 0; i < LP3952_LED_ALL; i++) {
>> +		sprintf(priv->leds[i].name, "%s", led_name[i]);
>> +		priv->leds[i].cdev.name = priv->leds[i].name;
>> +		priv->leds[i].cdev.brightness = LED_OFF;
>> +		priv->leds[i].cdev.max_brightness = LP3952_BRIGHT_MAX;
>> +		priv->leds[i].cdev.brightness_set_blocking =
>> +				lp3952_set_brightness;
>> +		priv->leds[i].channel = i;
>> +		priv->leds[i].priv = priv;
>> +
>> +		ret = devm_led_classdev_register(&priv->client->dev,
>> +						 &priv->leds[i].cdev);
>> +		if (ret < 0) {
>> +			dev_err(&priv->client->dev,
>> +				"couldn't register LED %s\n",
>> +				priv->leds[i].cdev.name);
>> +			break;
>> +		}
>> +	}
>> +	return ret;
>> +}
>> +
>> +static int lp3952_set_pattern_gen_cmd(struct lp3952_led_array *priv,
>> +				      u8 cmd_index, u8 r, u8 g, u8 b,
>> +				      enum lp3952_tt tt, enum lp3952_cet cet)
>> +{
>> +	int ret;
>> +	struct ptrn_gen_cmd line = {
>> +		.r = r,
>> +		.g = g,
>> +		.b = b,
>> +		.cet = cet,
>> +		.tt = tt
>> +	};
>> +
>> +	if (cmd_index >= LP3952_CMD_REG_COUNT)
>> +		return -EINVAL;
>> +
>> +	ret = lp3952_register_write(priv->client,
>> +				    LP3952_REG_CMD_0 + cmd_index * 2,
>> +				    line.bytes.msb);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return (lp3952_register_write(priv->client,
>> +				      LP3952_REG_CMD_0 + cmd_index * 2 + 1,
>> +				      line.bytes.lsb));
>> +}
>> +
>> +static int lp3952_configure(struct lp3952_led_array *priv)
>> +{
>> +	int ret;
>> +
>> +	/* Disable any LEDs on from any previous conf. */
>> +	ret = lp3952_register_write(priv->client, LP3952_REG_LED_CTRL, 0);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* enable rgb patter, loop */
>> +	ret = lp3952_register_write(priv->client, LP3952_REG_PAT_GEN_CTRL,
>> +				    LP3952_PATRN_LOOP | LP3952_PATRN_GEN_EN);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* Update Bit 6 (Active mode), Select both Led sets, Bit [1:0] */
>> +	ret = lp3952_register_write(priv->client, LP3952_REG_ENABLES,
>> +				    LP3952_ACTIVE_MODE | LP3952_INT_B00ST_LDR);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* Set Cmd1 for RGB intensity,cmd and transition time */
>> +	return (lp3952_set_pattern_gen_cmd(priv, 0, I46, I71, I100, TT0,
>> +					   CET197));
>> +}
>> +
>> +static const struct regmap_config lp3952_regmap = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +	.max_register = REG_MAX,
>> +	.cache_type = REGCACHE_RBTREE,
>> +};
>> +
>> +static int lp3952_probe(struct i2c_client *client,
>> +			const struct i2c_device_id *id)
>> +{
>> +	int status;
>> +	struct lp3952_ctrl_hdl *leds;
>> +	struct lp3952_led_array *priv;
>> +
>> +	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	leds = devm_kcalloc(&client->dev, LP3952_LED_ALL, sizeof(*leds),
>> +			    GFP_KERNEL);
>> +	if (!leds) {
>> +		devm_kfree(&client->dev, priv);
>> +		return -ENOMEM;
>> +	}
>> +
>> +	priv->leds = leds;
>> +	priv->client = client;
>> +
>> +	priv->enable_gpio = devm_gpiod_get(&client->dev, NULL, GPIOD_OUT_HIGH);
>> +	if (IS_ERR(priv->enable_gpio)) {
>> +		status = PTR_ERR(priv->enable_gpio);
>> +		dev_err(&client->dev, "Failed to enable gpio: %d\n", status);
>> +		return status;
>> +	}
>> +
>> +	priv->regmap = devm_regmap_init_i2c(client, &lp3952_regmap);
>> +	if (IS_ERR(priv->regmap)) {
>> +		int err = PTR_ERR(priv->regmap);
>> +
>> +		dev_err(&client->dev, "Failed to allocate register map: %d\n",
>> +			err);
>> +		return err;
>> +	}
>> +
>> +	i2c_set_clientdata(client, priv);
>> +
>> +	status = lp3952_configure(priv);
>> +	if (status) {
>> +		dev_err(&client->dev, "Probe failed. Device not found (%d)\n",
>> +			status);
>> +		return status;
>> +	}
>> +
>> +	status = lp3952_register_led_classdev(priv);
>> +	if (status) {
>> +		dev_err(&client->dev, "Unable to register led_classdev: %d\n",
>> +			status);
>> +		return status;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int lp3952_remove(struct i2c_client *client)
>> +{
>> +	struct lp3952_led_array *priv;
>> +
>> +	priv = i2c_get_clientdata(client);
>> +	lp3952_on_off(priv, LP3952_LED_ALL, 0);
>> +	gpiod_set_value(priv->enable_gpio, 0);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct i2c_device_id lp3952_id[] = {
>> +	{LP3952_NAME, 0},
>> +	{}
>> +};
>> +
>> +#ifdef CONFIG_ACPI
>> +static const struct acpi_device_id lp3952_acpi_match[] = {
>> +	{LP3952_ACPI_NAME, 0},
>
> No, you can't use "PRP0001" in this list.
>
>> +	{}
>> +};
>> +
>> +MODULE_DEVICE_TABLE(acpi, lp3952_acpi_match);
>
> And you don't need this for the "PRP0001" thing to work.  The core will
> take care of it for you then.
>
>> +#endif
>
> So the entire ACPI block can be dropped for now.
>
> And the driver doesn't have to depend on CONFIG_ACPI any more, does it?

The driver currently supports probing only with ACPI.
I have one question BTW: isn't there anything similar to the device tree
bindings documentation required for ACPI overlays?
Pointer to the discussion which led us to this solution:

http://www.spinics.net/lists/linux-leds/msg06230.html


>> +
>> +static struct i2c_driver lp3952_i2c_driver = {
>> +	.driver = {
>> +		   .name = LP3952_NAME,
>> +		   .acpi_match_table = ACPI_PTR(lp3952_acpi_match),
>> +		  },
>> +	.probe = lp3952_probe,
>> +	.remove = lp3952_remove,
>> +	.id_table = lp3952_id,
>> +};
>> +
>> +module_i2c_driver(lp3952_i2c_driver);
>> +
>> +MODULE_AUTHOR("Tony Makkiel <tony.makkiel@daqri.com>");
>> +MODULE_DESCRIPTION("lp3952 I2C LED controller driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/include/linux/leds-lp3952.h b/include/linux/leds-lp3952.h
>> new file mode 100644
>> index 0000000..9808ab7
>> --- /dev/null
>> +++ b/include/linux/leds-lp3952.h
>> @@ -0,0 +1,128 @@
>> +/*
>> + *	LED driver for TI lp3952 controller
>> + *
>> + *	Copyright (C) 2016, DAQRI, LLC.
>> + *	Author: Tony Makkiel <tony.makkiel@daqri.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.
>> + *
>> + */
>> +
>> +#ifndef LEDS_LP3952_H_
>> +#define LEDS_LP3952_H_
>> +
>> +/* ACPI iasl compiler wont take name LP3952,
>> + * "ASL_MSG_HID_LENGTH". Hence the name TLP3952
>> + */
>> +#define LP3952_NAME                         "lp3952"
>> +#define LP3952_ACPI_NAME                    "PRP0001"
>
> This is not necessary.
>
>> +#define LP3952_CMD_REG_COUNT                8
>> +#define LP3952_BRIGHT_MAX                   4
>> +
>> +#define LP3952_REG_LED_CTRL                 0x00
>> +#define LP3952_REG_R1_BLNK_TIME_CTRL        0x01
>> +#define LP3952_REG_R1_BLNK_CYCLE_CTRL       0x02
>> +#define LP3952_REG_G1_BLNK_TIME_CTRL        0x03
>> +#define LP3952_REG_G1_BLNK_CYCLE_CTRL       0x04
>> +#define LP3952_REG_B1_BLNK_TIME_CTRL        0x05
>> +#define LP3952_REG_B1_BLNK_CYCLE_CTRL       0x06
>> +#define LP3952_REG_ENABLES                  0x0B
>> +#define LP3952_REG_PAT_GEN_CTRL             0x11
>> +#define LP3952_REG_RGB1_MAX_I_CTRL          0x12
>> +#define LP3952_REG_RGB2_MAX_I_CTRL          0x13
>> +#define LP3952_REG_CMD_0                    0x50
>> +#define LP3952_REG_RESET                    0x60
>> +#define REG_MAX                             LP3952_REG_RESET
>> +
>> +#define LP3952_PATRN_LOOP                   BIT(1)
>> +#define LP3952_PATRN_GEN_EN                 BIT(2)
>> +#define LP3952_INT_B00ST_LDR                BIT(2)
>> +#define LP3952_ACTIVE_MODE                  BIT(6)
>> +#define LP3952_LED_MASK_ALL                 0x3f
>> +
>> +/* Transition Time in ms */
>> +enum lp3952_tt {
>> +	TT0,
>> +	TT55,
>> +	TT110,
>> +	TT221,
>> +	TT422,
>> +	TT885,
>> +	TT1770,
>> +	TT3539
>> +};
>> +
>> +/* Command Execution Time in ms */
>> +enum lp3952_cet {
>> +	CET197,
>> +	CET393,
>> +	CET590,
>> +	CET786,
>> +	CET1180,
>> +	CET1376,
>> +	CET1573,
>> +	CET1769,
>> +	CET1966,
>> +	CET2163,
>> +	CET2359,
>> +	CET2556,
>> +	CET2763,
>> +	CET2949,
>> +	CET3146
>> +};
>> +
>> +/* Max Current in % */
>> +enum lp3952_colour_I_log_0 {
>> +	I0,
>> +	I7,
>> +	I14,
>> +	I21,
>> +	I32,
>> +	I46,
>> +	I71,
>> +	I100
>> +};
>> +
>> +enum lp3952_leds {
>> +	LP3952_BLUE_2,
>> +	LP3952_GREEN_2,
>> +	LP3952_RED_2,
>> +	LP3952_BLUE_1,
>> +	LP3952_GREEN_1,
>> +	LP3952_RED_1,
>> +	LP3952_LED_ALL
>> +};
>> +
>> +struct lp3952_ctrl_hdl {
>> +	struct led_classdev cdev;
>> +	char name[15];
>> +	enum lp3952_leds channel;
>> +	void *priv;
>> +};
>> +
>> +struct ptrn_gen_cmd {
>> +	union {
>> +		struct {
>> +			u16 tt:3;
>> +			u16 b:3;
>> +			u16 cet:4;
>> +			u16 g:3;
>> +			u16 r:3;
>> +		};
>> +		struct {
>> +			u8 lsb;
>> +			u8 msb;
>> +		} bytes;
>> +	};
>> +} __packed;
>> +
>> +struct lp3952_led_array {
>> +	struct regmap *regmap;
>> +	struct i2c_client *client;
>> +	struct gpio_desc *enable_gpio;
>> +	struct lp3952_ctrl_hdl *leds;
>> +};
>> +
>> +#endif /* LEDS_LP3952_H_ */
>
> Thanks,
> Rafael
>
>
>


-- 
Best regards,
Jacek Anaszewski