250 строки
6.0 KiB
C
250 строки
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright (C) 2013 - 2014 Texas Instruments Incorporated - http://www.ti.com
|
|
*
|
|
* Authors:
|
|
* Jyri Sarha <jsarha@ti.com>
|
|
* Sergej Sawazki <ce3a@gmx.de>
|
|
*
|
|
* Gpio controlled clock implementation
|
|
*/
|
|
|
|
#include <linux/clk-provider.h>
|
|
#include <linux/export.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/gpio/consumer.h>
|
|
#include <linux/err.h>
|
|
#include <linux/device.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/of_device.h>
|
|
|
|
/**
|
|
* DOC: basic gpio gated clock which can be enabled and disabled
|
|
* with gpio output
|
|
* Traits of this clock:
|
|
* prepare - clk_(un)prepare only ensures parent is (un)prepared
|
|
* enable - clk_enable and clk_disable are functional & control gpio
|
|
* rate - inherits rate from parent. No clk_set_rate support
|
|
* parent - fixed parent. No clk_set_parent support
|
|
*/
|
|
|
|
/**
|
|
* struct clk_gpio - gpio gated clock
|
|
*
|
|
* @hw: handle between common and hardware-specific interfaces
|
|
* @gpiod: gpio descriptor
|
|
*
|
|
* Clock with a gpio control for enabling and disabling the parent clock
|
|
* or switching between two parents by asserting or deasserting the gpio.
|
|
*
|
|
* Implements .enable, .disable and .is_enabled or
|
|
* .get_parent, .set_parent and .determine_rate depending on which clk_ops
|
|
* is used.
|
|
*/
|
|
struct clk_gpio {
|
|
struct clk_hw hw;
|
|
struct gpio_desc *gpiod;
|
|
};
|
|
|
|
#define to_clk_gpio(_hw) container_of(_hw, struct clk_gpio, hw)
|
|
|
|
static int clk_gpio_gate_enable(struct clk_hw *hw)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
gpiod_set_value(clk->gpiod, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void clk_gpio_gate_disable(struct clk_hw *hw)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
gpiod_set_value(clk->gpiod, 0);
|
|
}
|
|
|
|
static int clk_gpio_gate_is_enabled(struct clk_hw *hw)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
return gpiod_get_value(clk->gpiod);
|
|
}
|
|
|
|
static const struct clk_ops clk_gpio_gate_ops = {
|
|
.enable = clk_gpio_gate_enable,
|
|
.disable = clk_gpio_gate_disable,
|
|
.is_enabled = clk_gpio_gate_is_enabled,
|
|
};
|
|
|
|
static int clk_sleeping_gpio_gate_prepare(struct clk_hw *hw)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
gpiod_set_value_cansleep(clk->gpiod, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void clk_sleeping_gpio_gate_unprepare(struct clk_hw *hw)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
gpiod_set_value_cansleep(clk->gpiod, 0);
|
|
}
|
|
|
|
static int clk_sleeping_gpio_gate_is_prepared(struct clk_hw *hw)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
return gpiod_get_value_cansleep(clk->gpiod);
|
|
}
|
|
|
|
static const struct clk_ops clk_sleeping_gpio_gate_ops = {
|
|
.prepare = clk_sleeping_gpio_gate_prepare,
|
|
.unprepare = clk_sleeping_gpio_gate_unprepare,
|
|
.is_prepared = clk_sleeping_gpio_gate_is_prepared,
|
|
};
|
|
|
|
/**
|
|
* DOC: basic clock multiplexer which can be controlled with a gpio output
|
|
* Traits of this clock:
|
|
* prepare - clk_prepare only ensures that parents are prepared
|
|
* rate - rate is only affected by parent switching. No clk_set_rate support
|
|
* parent - parent is adjustable through clk_set_parent
|
|
*/
|
|
|
|
static u8 clk_gpio_mux_get_parent(struct clk_hw *hw)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
return gpiod_get_value_cansleep(clk->gpiod);
|
|
}
|
|
|
|
static int clk_gpio_mux_set_parent(struct clk_hw *hw, u8 index)
|
|
{
|
|
struct clk_gpio *clk = to_clk_gpio(hw);
|
|
|
|
gpiod_set_value_cansleep(clk->gpiod, index);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct clk_ops clk_gpio_mux_ops = {
|
|
.get_parent = clk_gpio_mux_get_parent,
|
|
.set_parent = clk_gpio_mux_set_parent,
|
|
.determine_rate = __clk_mux_determine_rate,
|
|
};
|
|
|
|
static struct clk_hw *clk_register_gpio(struct device *dev, u8 num_parents,
|
|
struct gpio_desc *gpiod,
|
|
const struct clk_ops *clk_gpio_ops)
|
|
{
|
|
struct clk_gpio *clk_gpio;
|
|
struct clk_hw *hw;
|
|
struct clk_init_data init = {};
|
|
int err;
|
|
const struct clk_parent_data gpio_parent_data[] = {
|
|
{ .index = 0 },
|
|
{ .index = 1 },
|
|
};
|
|
|
|
clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio), GFP_KERNEL);
|
|
if (!clk_gpio)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
init.name = dev->of_node->name;
|
|
init.ops = clk_gpio_ops;
|
|
init.parent_data = gpio_parent_data;
|
|
init.num_parents = num_parents;
|
|
init.flags = CLK_SET_RATE_PARENT;
|
|
|
|
clk_gpio->gpiod = gpiod;
|
|
clk_gpio->hw.init = &init;
|
|
|
|
hw = &clk_gpio->hw;
|
|
err = devm_clk_hw_register(dev, hw);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
|
|
return hw;
|
|
}
|
|
|
|
static struct clk_hw *clk_hw_register_gpio_gate(struct device *dev,
|
|
int num_parents,
|
|
struct gpio_desc *gpiod)
|
|
{
|
|
const struct clk_ops *ops;
|
|
|
|
if (gpiod_cansleep(gpiod))
|
|
ops = &clk_sleeping_gpio_gate_ops;
|
|
else
|
|
ops = &clk_gpio_gate_ops;
|
|
|
|
return clk_register_gpio(dev, num_parents, gpiod, ops);
|
|
}
|
|
|
|
static struct clk_hw *clk_hw_register_gpio_mux(struct device *dev,
|
|
struct gpio_desc *gpiod)
|
|
{
|
|
return clk_register_gpio(dev, 2, gpiod, &clk_gpio_mux_ops);
|
|
}
|
|
|
|
static int gpio_clk_driver_probe(struct platform_device *pdev)
|
|
{
|
|
struct device *dev = &pdev->dev;
|
|
struct device_node *node = dev->of_node;
|
|
const char *gpio_name;
|
|
unsigned int num_parents;
|
|
struct gpio_desc *gpiod;
|
|
struct clk_hw *hw;
|
|
bool is_mux;
|
|
int ret;
|
|
|
|
is_mux = of_device_is_compatible(node, "gpio-mux-clock");
|
|
|
|
num_parents = of_clk_get_parent_count(node);
|
|
if (is_mux && num_parents != 2) {
|
|
dev_err(dev, "mux-clock must have 2 parents\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
gpio_name = is_mux ? "select" : "enable";
|
|
gpiod = devm_gpiod_get(dev, gpio_name, GPIOD_OUT_LOW);
|
|
if (IS_ERR(gpiod)) {
|
|
ret = PTR_ERR(gpiod);
|
|
if (ret == -EPROBE_DEFER)
|
|
pr_debug("%pOFn: %s: GPIOs not yet available, retry later\n",
|
|
node, __func__);
|
|
else
|
|
pr_err("%pOFn: %s: Can't get '%s' named GPIO property\n",
|
|
node, __func__,
|
|
gpio_name);
|
|
return ret;
|
|
}
|
|
|
|
if (is_mux)
|
|
hw = clk_hw_register_gpio_mux(dev, gpiod);
|
|
else
|
|
hw = clk_hw_register_gpio_gate(dev, num_parents, gpiod);
|
|
if (IS_ERR(hw))
|
|
return PTR_ERR(hw);
|
|
|
|
return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw);
|
|
}
|
|
|
|
static const struct of_device_id gpio_clk_match_table[] = {
|
|
{ .compatible = "gpio-mux-clock" },
|
|
{ .compatible = "gpio-gate-clock" },
|
|
{ }
|
|
};
|
|
|
|
static struct platform_driver gpio_clk_driver = {
|
|
.probe = gpio_clk_driver_probe,
|
|
.driver = {
|
|
.name = "gpio-clk",
|
|
.of_match_table = gpio_clk_match_table,
|
|
},
|
|
};
|
|
builtin_platform_driver(gpio_clk_driver);
|