linux/drivers/pwm/pwm-clk.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Clock based PWM controller
 *
 * Copyright (c) 2021 Nikita Travkin <[email protected]>
 *
 * This is an "adapter" driver that allows PWM consumers to use
 * system clocks with duty cycle control as PWM outputs.
 *
 * Limitations:
 * - Due to the fact that exact behavior depends on the underlying
 *   clock driver, various limitations are possible.
 * - Underlying clock may not be able to give 0% or 100% duty cycle
 *   (constant off or on), exact behavior will depend on the clock.
 * - When the PWM is disabled, the clock will be disabled as well,
 *   line state will depend on the clock.
 * - The clk API doesn't expose the necessary calls to implement
 *   .get_state().
 */

#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/pwm.h>

struct pwm_clk_chip { … };

static inline struct pwm_clk_chip *to_pwm_clk_chip(struct pwm_chip *chip)
{ … }

static int pwm_clk_apply(struct pwm_chip *chip, struct pwm_device *pwm,
			 const struct pwm_state *state)
{ … }

static const struct pwm_ops pwm_clk_ops = …;

static int pwm_clk_probe(struct platform_device *pdev)
{ … }

static void pwm_clk_remove(struct platform_device *pdev)
{ … }

static const struct of_device_id pwm_clk_dt_ids[] = …;
MODULE_DEVICE_TABLE(of, pwm_clk_dt_ids);

static struct platform_driver pwm_clk_driver = …;
module_platform_driver(…) …;

MODULE_ALIAS(…) …;
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;