Commit 88b613e6 authored by Steffen Trumtrar's avatar Steffen Trumtrar Committed by Thierry Reding
Browse files

pwm: add pca9685 driver 



Add pwm driver for the NXP pca9685 16 channel pwm-led controller.

The driver is really barebones at this stage. E.g. the OE' pin and
therefore the corresponding registers are not supported.
The driver was tested on a HW where this pin is tied to GND.

Signed-off-by: default avatarSteffen Trumtrar <s.trumtrar@pengutronix.de>
[thierry.reding@gmail.com: style and whitespace cleanups]
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 8796f9c5

Documentation/devicetree/bindings/pwm/nxp,pca9685-pwm.txt

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NXP PCA9685 16-channel 12-bit PWM LED controller

================================================



Required properties:

  - compatible: "nxp,pca9685-pwm"

  - #pwm-cells: should be 2. The first cell specifies the per-chip index

    of the PWM to use and the second cell is the period in nanoseconds.

    The index 16 is the ALLCALL channel, that sets all PWM channels at the same

    time.



Optional properties:

  - invert (bool): boolean to enable inverted logic

  - open-drain (bool): boolean to configure outputs with open-drain structure;

		       if omitted use totem-pole structure



Example:



For LEDs that are directly connected to the PCA, the following setting is

applicable:



pca: pca@41 {

	compatible = "nxp,pca9685-pwm";

	#pwm-cells = <2>;

	reg = <0x41>;

	invert;

	open-drain;

};

drivers/pwm/Kconfig

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@@ -97,6 +97,15 @@ config PWM_MXS 
	  To compile this driver as a module, choose M here: the module

	  will be called pwm-mxs.



config PWM_PCA9685

	tristate "NXP PCA9685 PWM driver"

	depends on OF && REGMAP_I2C

	help

	  Generic PWM framework driver for NXP PCA9685 LED controller.



	  To compile this driver as a module, choose M here: the module

	  will be called pwm-pca9685.



config PWM_PUV3

	tristate "PKUnity NetBook-0916 PWM support"

	depends on ARCH_PUV3

drivers/pwm/Makefile

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@@ -6,6 +6,7 @@ obj-$(CONFIG_PWM_IMX) += pwm-imx.o 
obj-$(CONFIG_PWM_JZ4740)	+= pwm-jz4740.o

obj-$(CONFIG_PWM_LPC32XX)	+= pwm-lpc32xx.o

obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o

obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o

obj-$(CONFIG_PWM_PUV3)		+= pwm-puv3.o

obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o

obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o

drivers/pwm/pwm-pca9685.c

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/*

 * Driver for PCA9685 16-channel 12-bit PWM LED controller

 *

 * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>

 *

 * based on the pwm-twl-led.c driver

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program.  If not, see <http://www.gnu.org/licenses/>.

 */



#include <linux/i2c.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/pwm.h>

#include <linux/regmap.h>

#include <linux/slab.h>



#define PCA9685_MODE1		0x00

#define PCA9685_MODE2		0x01

#define PCA9685_SUBADDR1	0x02

#define PCA9685_SUBADDR2	0x03

#define PCA9685_SUBADDR3	0x04

#define PCA9685_ALLCALLADDR	0x05

#define PCA9685_LEDX_ON_L	0x06

#define PCA9685_LEDX_ON_H	0x07

#define PCA9685_LEDX_OFF_L	0x08

#define PCA9685_LEDX_OFF_H	0x09



#define PCA9685_ALL_LED_ON_L	0xFA

#define PCA9685_ALL_LED_ON_H	0xFB

#define PCA9685_ALL_LED_OFF_L	0xFC

#define PCA9685_ALL_LED_OFF_H	0xFD

#define PCA9685_PRESCALE	0xFE



#define PCA9685_NUMREGS		0xFF

#define PCA9685_MAXCHAN		0x10



#define LED_FULL		(1 << 4)

#define MODE1_SLEEP		(1 << 4)

#define MODE2_INVRT		(1 << 4)

#define MODE2_OUTDRV		(1 << 2)



#define LED_N_ON_H(N)	(PCA9685_LEDX_ON_H + (4 * (N)))

#define LED_N_ON_L(N)	(PCA9685_LEDX_ON_L + (4 * (N)))

#define LED_N_OFF_H(N)	(PCA9685_LEDX_OFF_H + (4 * (N)))

#define LED_N_OFF_L(N)	(PCA9685_LEDX_OFF_L + (4 * (N)))



struct pca9685 {

	struct pwm_chip chip;

	struct regmap *regmap;

	int active_cnt;

};



static inline struct pca9685 *to_pca(struct pwm_chip *chip)

{

	return container_of(chip, struct pca9685, chip);

}



static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,

			      int duty_ns, int period_ns)

{

	struct pca9685 *pca = to_pca(chip);

	unsigned long long duty;

	unsigned int reg;



	if (duty_ns < 1) {

		if (pwm->hwpwm >= PCA9685_MAXCHAN)

			reg = PCA9685_ALL_LED_OFF_H;

		else

			reg = LED_N_OFF_H(pwm->hwpwm);



		regmap_write(pca->regmap, reg, LED_FULL);



		return 0;

	}



	if (duty_ns == period_ns) {

		if (pwm->hwpwm >= PCA9685_MAXCHAN)

			reg = PCA9685_ALL_LED_ON_H;

		else

			reg = LED_N_ON_H(pwm->hwpwm);



		regmap_write(pca->regmap, reg, LED_FULL);



		return 0;

	}



	duty = 4096 * (unsigned long long)duty_ns;

	duty = DIV_ROUND_UP_ULL(duty, period_ns);



	if (pwm->hwpwm >= PCA9685_MAXCHAN)

		reg = PCA9685_ALL_LED_OFF_L;

	else

		reg = LED_N_OFF_L(pwm->hwpwm);



	regmap_write(pca->regmap, reg, (int)duty & 0xff);



	if (pwm->hwpwm >= PCA9685_MAXCHAN)

		reg = PCA9685_ALL_LED_OFF_H;

	else

		reg = LED_N_OFF_H(pwm->hwpwm);



	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);



	return 0;

}



static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)

{

	struct pca9685 *pca = to_pca(chip);

	unsigned int reg;



	/*

	 * The PWM subsystem does not support a pre-delay.

	 * So, set the ON-timeout to 0

	 */

	if (pwm->hwpwm >= PCA9685_MAXCHAN)

		reg = PCA9685_ALL_LED_ON_L;

	else

		reg = LED_N_ON_L(pwm->hwpwm);



	regmap_write(pca->regmap, reg, 0);



	if (pwm->hwpwm >= PCA9685_MAXCHAN)

		reg = PCA9685_ALL_LED_ON_H;

	else

		reg = LED_N_ON_H(pwm->hwpwm);



	regmap_write(pca->regmap, reg, 0);



	/*

	 * Clear the full-off bit.

	 * It has precedence over the others and must be off.

	 */

	if (pwm->hwpwm >= PCA9685_MAXCHAN)

		reg = PCA9685_ALL_LED_OFF_H;

	else

		reg = LED_N_OFF_H(pwm->hwpwm);



	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);



	return 0;

}



static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)

{

	struct pca9685 *pca = to_pca(chip);

	unsigned int reg;



	if (pwm->hwpwm >= PCA9685_MAXCHAN)

		reg = PCA9685_ALL_LED_OFF_H;

	else

		reg = LED_N_OFF_H(pwm->hwpwm);



	regmap_write(pca->regmap, reg, LED_FULL);



	/* Clear the LED_OFF counter. */

	if (pwm->hwpwm >= PCA9685_MAXCHAN)

		reg = PCA9685_ALL_LED_OFF_L;

	else

		reg = LED_N_OFF_L(pwm->hwpwm);



	regmap_write(pca->regmap, reg, 0x0);

}



static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)

{

	struct pca9685 *pca = to_pca(chip);



	if (pca->active_cnt++ == 0)

		return regmap_update_bits(pca->regmap, PCA9685_MODE1,

					  MODE1_SLEEP, 0x0);



	return 0;

}



static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)

{

	struct pca9685 *pca = to_pca(chip);



	if (--pca->active_cnt == 0)

		regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,

				   0x1);

}



static const struct pwm_ops pca9685_pwm_ops = {

	.enable = pca9685_pwm_enable,

	.disable = pca9685_pwm_disable,

	.config = pca9685_pwm_config,

	.request = pca9685_pwm_request,

	.free = pca9685_pwm_free,

};



static struct regmap_config pca9685_regmap_i2c_config = {

	.reg_bits = 8,

	.val_bits = 8,

	.max_register = PCA9685_NUMREGS,

	.cache_type = REGCACHE_NONE,

};



static int pca9685_pwm_probe(struct i2c_client *client,

				const struct i2c_device_id *id)

{

	struct device_node *np = client->dev.of_node;

	struct pca9685 *pca;

	int ret;

	int mode2;



	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);

	if (!pca)

		return -ENOMEM;



	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);

	if (IS_ERR(pca->regmap)) {

		ret = PTR_ERR(pca->regmap);

		dev_err(&client->dev, "Failed to initialize register map: %d\n",

			ret);

		return ret;

	}



	i2c_set_clientdata(client, pca);



	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);



	if (of_property_read_bool(np, "invert"))

		mode2 |= MODE2_INVRT;

	else

		mode2 &= ~MODE2_INVRT;



	if (of_property_read_bool(np, "open-drain"))

		mode2 &= ~MODE2_OUTDRV;

	else

		mode2 |= MODE2_OUTDRV;



	regmap_write(pca->regmap, PCA9685_MODE2, mode2);



	/* clear all "full off" bits */

	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);

	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);



	pca->chip.ops = &pca9685_pwm_ops;

	/* add an extra channel for ALL_LED */

	pca->chip.npwm = PCA9685_MAXCHAN + 1;



	pca->chip.dev = &client->dev;

	pca->chip.base = -1;

	pca->chip.can_sleep = true;



	return pwmchip_add(&pca->chip);

}



static int pca9685_pwm_remove(struct i2c_client *client)

{

	struct pca9685 *pca = i2c_get_clientdata(client);



	regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP, 0x1);



	return pwmchip_remove(&pca->chip);

}



static const struct i2c_device_id pca9685_id[] = {

	{ "pca9685", 0 },

	{ /* sentinel */ },

};

MODULE_DEVICE_TABLE(i2c, pca9685_id);



static const struct of_device_id pca9685_dt_ids[] = {

	{ .compatible = "nxp,pca9685-pwm", },

	{ /* sentinel */ }

};

MODULE_DEVICE_TABLE(of, pca9685_dt_ids);



static struct i2c_driver pca9685_i2c_driver = {

	.driver = {

		.name = "pca9685-pwm",

		.owner = THIS_MODULE,

		.of_match_table = pca9685_dt_ids,

	},

	.probe = pca9685_pwm_probe,

	.remove = pca9685_pwm_remove,

	.id_table = pca9685_id,

};



module_i2c_driver(pca9685_i2c_driver);



MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");

MODULE_DESCRIPTION("PWM driver for PCA9685");

MODULE_LICENSE("GPL");

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