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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* clk-gpio.c - clock that can be enabled and disabled via GPIO output
* Based on Linux clk support
*
* Copyright (c) 2018 Nikita Yushchenko <nikita.yoush@cogentembedded.com>
*/
#include <common.h>
#include <malloc.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <gpio.h>
#include <of_gpio.h>
#include <init.h>
struct clk_gpio {
struct clk clk;
const char *parent;
int gpio;
};
#define to_clk_gpio(_clk) container_of(_clk, struct clk_gpio, clk)
static int clk_gpio_enable(struct clk *clk)
{
struct clk_gpio *clk_gpio = to_clk_gpio(clk);
gpio_set_active(clk_gpio->gpio, true);
return 0;
}
static void clk_gpio_disable(struct clk *clk)
{
struct clk_gpio *clk_gpio = to_clk_gpio(clk);
gpio_set_active(clk_gpio->gpio, false);
}
static int clk_gpio_is_enabled(struct clk *clk)
{
struct clk_gpio *clk_gpio = to_clk_gpio(clk);
return gpio_is_active(clk_gpio->gpio);
}
static struct clk_ops clk_gpio_ops = {
.set_rate = clk_parent_set_rate,
.round_rate = clk_parent_round_rate,
.enable = clk_gpio_enable,
.disable = clk_gpio_disable,
.is_enabled = clk_gpio_is_enabled,
};
static int of_gpio_clk_setup(struct device_node *node)
{
struct clk_gpio *clk_gpio;
enum of_gpio_flags of_flags;
unsigned long flags;
int ret;
clk_gpio = xzalloc(sizeof(*clk_gpio));
if (!clk_gpio)
return -ENOMEM;
clk_gpio->parent = of_clk_get_parent_name(node, 0);
if (!clk_gpio->parent) {
ret = -EINVAL;
goto no_parent;
}
clk_gpio->clk.ops = &clk_gpio_ops;
clk_gpio->clk.parent_names = &clk_gpio->parent;
clk_gpio->clk.num_parents = 1;
clk_gpio->clk.name = node->name;
of_property_read_string(node, "clock-output-names",
&clk_gpio->clk.name);
ret = of_get_named_gpio_flags(node, "enable-gpios", 0,
&of_flags);
if (ret >= 0 && !gpio_is_valid(ret))
ret = -EINVAL;
if (ret < 0)
goto no_gpio;
clk_gpio->gpio = ret;
flags = GPIOF_OUT_INIT_ACTIVE;
if (of_flags & OF_GPIO_ACTIVE_LOW)
flags |= GPIOF_ACTIVE_LOW;
ret = gpio_request_one(clk_gpio->gpio, flags, clk_gpio->clk.name);
if (ret)
goto no_request;
ret = clk_register(&clk_gpio->clk);
if (ret)
goto no_register;
return of_clk_add_provider(node, of_clk_src_simple_get, &clk_gpio->clk);
no_register:
gpio_free(clk_gpio->gpio);
no_request:
no_gpio:
no_parent:
free(clk_gpio);
return ret;
}
/* Can't use OF_CLK_DECLARE due to need to run after GPIOcontrollers have
* registrered */
static const struct of_device_id clk_gpio_device_id[] = {
{ .compatible = "gpio-gate-clock", .data = of_gpio_clk_setup, },
{}
};
static int clk_gpio_init(void)
{
return of_clk_init(NULL, clk_gpio_device_id);
}
coredevice_initcall(clk_gpio_init);
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