Quelle  sun6i_drc.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2016 Free Electrons
 *
 * Maxime Ripard <maxime.ripard@free-electrons.com>
 */

#include <linux/clk.h>
#include <linux/component.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset.h>

struct sun6i_drc {
 struct clk  *bus_clk;
 struct clk  *mod_clk;
 struct reset_control *reset;
};

static int sun6i_drc_bind(struct device *dev, struct device *master,
    void *data)
{
 struct sun6i_drc *drc;
 int ret;

 drc = devm_kzalloc(dev, sizeof(*drc), GFP_KERNEL);
 if (!drc)
  return -ENOMEM;
 dev_set_drvdata(dev, drc);

 drc->reset = devm_reset_control_get(dev, NULL);
 if (IS_ERR(drc->reset)) {
  dev_err(dev, "Couldn't get our reset line\n");
  return PTR_ERR(drc->reset);
 }

 ret = reset_control_deassert(drc->reset);
 if (ret) {
  dev_err(dev, "Couldn't deassert our reset line\n");
  return ret;
 }

 drc->bus_clk = devm_clk_get(dev, "ahb");
 if (IS_ERR(drc->bus_clk)) {
  dev_err(dev, "Couldn't get our bus clock\n");
  ret = PTR_ERR(drc->bus_clk);
  goto err_assert_reset;
 }
 clk_prepare_enable(drc->bus_clk);

 drc->mod_clk = devm_clk_get(dev, "mod");
 if (IS_ERR(drc->mod_clk)) {
  dev_err(dev, "Couldn't get our mod clock\n");
  ret = PTR_ERR(drc->mod_clk);
  goto err_disable_bus_clk;
 }

 ret = clk_set_rate_exclusive(drc->mod_clk, 300000000);
 if (ret) {
  dev_err(dev, "Couldn't set the module clock frequency\n");
  goto err_disable_bus_clk;
 }

 clk_prepare_enable(drc->mod_clk);

 return 0;

err_disable_bus_clk:
 clk_disable_unprepare(drc->bus_clk);
err_assert_reset:
 reset_control_assert(drc->reset);
 return ret;
}

static void sun6i_drc_unbind(struct device *dev, struct device *master,
       void *data)
{
 struct sun6i_drc *drc = dev_get_drvdata(dev);

 clk_rate_exclusive_put(drc->mod_clk);
 clk_disable_unprepare(drc->mod_clk);
 clk_disable_unprepare(drc->bus_clk);
 reset_control_assert(drc->reset);
}

static const struct component_ops sun6i_drc_ops = {
 .bind = sun6i_drc_bind,
 .unbind = sun6i_drc_unbind,
};

static int sun6i_drc_probe(struct platform_device *pdev)
{
 return component_add(&pdev->dev, &sun6i_drc_ops);
}

static void sun6i_drc_remove(struct platform_device *pdev)
{
 component_del(&pdev->dev, &sun6i_drc_ops);
}

static const struct of_device_id sun6i_drc_of_table[] = {
 { .compatible = "allwinner,sun6i-a31-drc" },
 { .compatible = "allwinner,sun6i-a31s-drc" },
 { .compatible = "allwinner,sun8i-a23-drc" },
 { .compatible = "allwinner,sun8i-a33-drc" },
 { .compatible = "allwinner,sun9i-a80-drc" },
 { }
};
MODULE_DEVICE_TABLE(of, sun6i_drc_of_table);

static struct platform_driver sun6i_drc_platform_driver = {
 .probe  = sun6i_drc_probe,
 .remove  = sun6i_drc_remove,
 .driver  = {
  .name  = "sun6i-drc",
  .of_match_table = sun6i_drc_of_table,
 },
};
module_platform_driver(sun6i_drc_platform_driver);

MODULE_AUTHOR("Maxime Ripard ");
MODULE_DESCRIPTION("Allwinner A31 Dynamic Range Control (DRC) Driver");
MODULE_LICENSE("GPL");