linux-imx

/*

 * PWM framework driver for Cirrus Logic EP93xx

 *

 * Copyright (c) 2009        Matthieu Crapet <mcrapet@gmail.com>

 * Copyright (c) 2009, 2013  H Hartley Sweeten <hsweeten@visionengravers.com>

 *

 * EP9301/02 have only one channel:

 *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)

 *

 * EP9307 has only one channel:

 *   platform device ep93xx-pwm.0 - PWMOUT

 *

 * EP9312/15 have two channels:

 *   platform device ep93xx-pwm.0 - PWMOUT

 *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 *

 * 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.

 */

​

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/slab.h>

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/pwm.h>

​

#include <asm/div64.h>

​

#include <mach/platform.h>  /* for ep93xx_pwm_{acquire,release}_gpio() */

​

#define EP93XX_PWMx_TERM_COUNT  0x00

#define EP93XX_PWMx_DUTY_CYCLE  0x04

#define EP93XX_PWMx_ENABLE  0x08

#define EP93XX_PWMx_INVERT  0x0c

​

struct ep93xx_pwm {

    void __iomem *base;

    struct clk *clk;

    struct pwm_chip chip;

};

​

static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)

{

    return container_of(chip, struct ep93xx_pwm, chip);

}

​

static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)

{

    struct platform_device *pdev = to_platform_device(chip->dev);

​

    return ep93xx_pwm_acquire_gpio(pdev);

}

​

static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)

{

    struct platform_device *pdev = to_platform_device(chip->dev);

​

    ep93xx_pwm_release_gpio(pdev);

}

​

static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,

                 int duty_ns, int period_ns)

{

    struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);

    void __iomem *base = ep93xx_pwm->base;

    unsigned long long c;

    unsigned long period_cycles;

    unsigned long duty_cycles;

    unsigned long term;

    int ret = 0;

​

    /*

     * The clock needs to be enabled to access the PWM registers.

     * Configuration can be changed at any time.

     */

    if (!pwm_is_enabled(pwm)) {

        ret = clk_enable(ep93xx_pwm->clk);

        if (ret)

            return ret;

    }

​

    c = clk_get_rate(ep93xx_pwm->clk);

    c *= period_ns;