/*

   * drivers/pwm/pwm-pxa.c

   *
   * simple driver for PWM (Pulse Width Modulator) controller
   *
   * 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.
   *
   * 2008-02-13	initial version

   *		eric miao <eric.miao@marvell.com>

   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/platform_device.h>

  #include <linux/slab.h>

  #include <linux/err.h>
  #include <linux/clk.h>
  #include <linux/io.h>
  #include <linux/pwm.h>

  #include <linux/of_device.h>

  
  #include <asm/div64.h>

  #define HAS_SECONDARY_PWM	0x10
  
  static const struct platform_device_id pwm_id_table[] = {
  	/*   PWM    has_secondary_pwm? */
  	{ "pxa25x-pwm", 0 },

  	{ "pxa27x-pwm", HAS_SECONDARY_PWM },
  	{ "pxa168-pwm", 0 },
  	{ "pxa910-pwm", 0 },

  	{ },
  };
  MODULE_DEVICE_TABLE(platform, pwm_id_table);

  /* PWM registers and bits definitions */
  #define PWMCR		(0x00)
  #define PWMDCR		(0x04)
  #define PWMPCR		(0x08)
  
  #define PWMCR_SD	(1 << 6)
  #define PWMDCR_FD	(1 << 10)

  struct pxa_pwm_chip {
  	struct pwm_chip	chip;
  	struct device	*dev;

  	struct clk	*clk;
  	void __iomem	*mmio_base;

  };

  static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
  {
  	return container_of(chip, struct pxa_pwm_chip, chip);
  }

  /*
   * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
   * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
   */

  static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  			  int duty_ns, int period_ns)

  {

  	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);

  	unsigned long long c;
  	unsigned long period_cycles, prescale, pv, dc;

  	unsigned long offset;
  	int rc;

  	offset = pwm->hwpwm ? 0x10 : 0;
  
  	c = clk_get_rate(pc->clk);

  	c = c * period_ns;
  	do_div(c, 1000000000);
  	period_cycles = c;

  	if (period_cycles < 1)

  		period_cycles = 1;
  	prescale = (period_cycles - 1) / 1024;
  	pv = period_cycles / (prescale + 1) - 1;
  
  	if (prescale > 63)
  		return -EINVAL;
  
  	if (duty_ns == period_ns)
  		dc = PWMDCR_FD;
  	else
  		dc = (pv + 1) * duty_ns / period_ns;
  
  	/* NOTE: the clock to PWM has to be enabled first
  	 * before writing to the registers
  	 */

  	rc = clk_prepare_enable(pc->clk);
  	if (rc < 0)
  		return rc;
  
  	writel(prescale, pc->mmio_base + offset + PWMCR);
  	writel(dc, pc->mmio_base + offset + PWMDCR);
  	writel(pv, pc->mmio_base + offset + PWMPCR);

  	clk_disable_unprepare(pc->clk);

  	return 0;
  }

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

  {

  	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);

  	return clk_prepare_enable(pc->clk);

  }

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

  {

  	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);

  	clk_disable_unprepare(pc->clk);

  }

  static struct pwm_ops pxa_pwm_ops = {
  	.config = pxa_pwm_config,
  	.enable = pxa_pwm_enable,
  	.disable = pxa_pwm_disable,
  	.owner = THIS_MODULE,
  };

  #ifdef CONFIG_OF
  /*

   * Device tree users must create one device instance for each PWM channel.

   * Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver
   * code that this is a single channel pxa25x-pwm.  Currently all devices are
   * supported identically.
   */

  static const struct of_device_id pwm_of_match[] = {

  	{ .compatible = "marvell,pxa250-pwm", .data = &pwm_id_table[0]},
  	{ .compatible = "marvell,pxa270-pwm", .data = &pwm_id_table[0]},
  	{ .compatible = "marvell,pxa168-pwm", .data = &pwm_id_table[0]},
  	{ .compatible = "marvell,pxa910-pwm", .data = &pwm_id_table[0]},
  	{ }
  };
  MODULE_DEVICE_TABLE(of, pwm_of_match);

  #else
  #define pwm_of_match NULL

  #endif
  
  static const struct platform_device_id *pxa_pwm_get_id_dt(struct device *dev)
  {
  	const struct of_device_id *id = of_match_device(pwm_of_match, dev);
  
  	return id ? id->data : NULL;
  }
  
  static struct pwm_device *
  pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
  {
  	struct pwm_device *pwm;
  
  	pwm = pwm_request_from_chip(pc, 0, NULL);
  	if (IS_ERR(pwm))
  		return pwm;
  
  	pwm_set_period(pwm, args->args[0]);
  
  	return pwm;
  }

  static int pwm_probe(struct platform_device *pdev)

  {

  	const struct platform_device_id *id = platform_get_device_id(pdev);

  	struct pxa_pwm_chip *pwm;

  	struct resource *r;
  	int ret = 0;

  	if (IS_ENABLED(CONFIG_OF) && id == NULL)
  		id = pxa_pwm_get_id_dt(&pdev->dev);
  
  	if (id == NULL)
  		return -EINVAL;

  	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);

  	if (pwm == NULL)

  		return -ENOMEM;

  	pwm->clk = devm_clk_get(&pdev->dev, NULL);
  	if (IS_ERR(pwm->clk))
  		return PTR_ERR(pwm->clk);

  	pwm->chip.dev = &pdev->dev;
  	pwm->chip.ops = &pxa_pwm_ops;
  	pwm->chip.base = -1;
  	pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;

  	if (IS_ENABLED(CONFIG_OF)) {
  		pwm->chip.of_xlate = pxa_pwm_of_xlate;
  		pwm->chip.of_pwm_n_cells = 1;
  	}

  	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);

  	pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
  	if (IS_ERR(pwm->mmio_base))
  		return PTR_ERR(pwm->mmio_base);

  	ret = pwmchip_add(&pwm->chip);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "pwmchip_add() failed: %d
  ", ret);
  		return ret;

  	}

  	platform_set_drvdata(pdev, pwm);

  	return 0;

  }

  static int pwm_remove(struct platform_device *pdev)

  {

  	struct pxa_pwm_chip *chip;

  	chip = platform_get_drvdata(pdev);
  	if (chip == NULL)

  		return -ENODEV;

  	return pwmchip_remove(&chip->chip);

  }

  static struct platform_driver pwm_driver = {

  	.driver		= {
  		.name	= "pxa25x-pwm",

  		.of_match_table = pwm_of_match,

  	},

  	.probe		= pwm_probe,

  	.remove		= pwm_remove,

  	.id_table	= pwm_id_table,

  };

  module_platform_driver(pwm_driver);

  
  MODULE_LICENSE("GPL v2");