linux-imx

/*

 * Driver for TWL4030/6030 Generic Pulse Width Modulator

 *

 * Copyright (C) 2012 Texas Instruments

 * Author: Peter Ujfalusi <peter.ujfalusi@ti.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.

 *

 * 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/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/pwm.h>

#include <linux/mfd/twl.h>

#include <linux/slab.h>

​

/*

 * This driver handles the PWMs of TWL4030 and TWL6030.

 * The TRM names for the PWMs on TWL4030 are: PWM0, PWM1

 * TWL6030 also have two PWMs named in the TRM as PWM1, PWM2

 */

​

#define TWL_PWM_MAX     0x7f

​

/* Registers, bits and macro for TWL4030 */

#define TWL4030_GPBR1_REG   0x0c

#define TWL4030_PMBR1_REG   0x0d

​

/* GPBR1 register bits */

#define TWL4030_PWMXCLK_ENABLE  (1 << 0)

#define TWL4030_PWMX_ENABLE (1 << 2)

#define TWL4030_PWMX_BITS   (TWL4030_PWMX_ENABLE | TWL4030_PWMXCLK_ENABLE)

#define TWL4030_PWM_TOGGLE(pwm, x)  ((x) << (pwm))

​

/* PMBR1 register bits */

#define TWL4030_GPIO6_PWM0_MUTE_MASK        (0x03 << 2)

#define TWL4030_GPIO6_PWM0_MUTE_PWM0        (0x01 << 2)

#define TWL4030_GPIO7_VIBRASYNC_PWM1_MASK   (0x03 << 4)

#define TWL4030_GPIO7_VIBRASYNC_PWM1_PWM1   (0x03 << 4)

​

/* Register, bits and macro for TWL6030 */

#define TWL6030_TOGGLE3_REG 0x92

​

#define TWL6030_PWMXR       (1 << 0)

#define TWL6030_PWMXS       (1 << 1)

#define TWL6030_PWMXEN      (1 << 2)

#define TWL6030_PWM_TOGGLE(pwm, x)  ((x) << (pwm * 3))

​

struct twl_pwm_chip {

    struct pwm_chip chip;

    struct mutex mutex;

    u8 twl6030_toggle3;

    u8 twl4030_pwm_mux;

};

​

static inline struct twl_pwm_chip *to_twl(struct pwm_chip *chip)

{

    return container_of(chip, struct twl_pwm_chip, chip);

}

​

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

                  int duty_ns, int period_ns)

{

    int duty_cycle = DIV_ROUND_UP(duty_ns * TWL_PWM_MAX, period_ns) + 1;

    u8 pwm_config[2] = { 1, 0 };

    int base, ret;

​

    /*

     * To configure the duty period:

     * On-cycle is set to 1 (the minimum allowed value)

     * The off time of 0 is not configurable, so the mapping is:

     * 0 -> off cycle = 2,

     * 1 -> off cycle = 2,

     * 2 -> off cycle = 3,

     * 126 - > off cycle 127,

     * 127 - > off cycle 1

     * When on cycle == off cycle the PWM will be always on

     */

    if (duty_cycle == 1)

        duty_cycle = 2;

    else if (duty_cycle > TWL_PWM_MAX)

        duty_cycle = 1;