Revision b4cd08aa1f53c831e67dc5c6bc9f9acff27abcba authored by Wolfram Sang on 16 December 2015, 19:05:18 UTC, committed by Wolfram Sang on 19 December 2015, 11:00:37 UTC
When we also are I2C slave, we need to disable runtime PM because the address detection mechanism needs to be active all the time. However, we can reenable runtime PM once the slave instance was unregistered. So, use pm_runtime_get_sync/put to achieve this, since it has proper refcounting. pm_runtime_allow/forbid is like a global knob controllable from userspace which is unsuitable here. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Cc: stable@kernel.org
1 parent e79e72c
clk-gpio.c
/*
* Copyright (C) 2013 - 2014 Texas Instruments Incorporated - http://www.ti.com
*
* Authors:
* Jyri Sarha <jsarha@ti.com>
* Sergej Sawazki <ce3a@gmx.de>
*
* 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.
*
* Gpio controlled clock implementation
*/
#include <linux/clk-provider.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/of_gpio.h>
#include <linux/err.h>
#include <linux/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
*/
#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);
}
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,
};
EXPORT_SYMBOL_GPL(clk_gpio_gate_ops);
/**
* 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(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(clk->gpiod, index);
return 0;
}
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,
};
EXPORT_SYMBOL_GPL(clk_gpio_mux_ops);
static struct clk *clk_register_gpio(struct device *dev, const char *name,
const char * const *parent_names, u8 num_parents, unsigned gpio,
bool active_low, unsigned long flags,
const struct clk_ops *clk_gpio_ops)
{
struct clk_gpio *clk_gpio;
struct clk *clk;
struct clk_init_data init = {};
unsigned long gpio_flags;
int err;
if (dev)
clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio), GFP_KERNEL);
else
clk_gpio = kzalloc(sizeof(*clk_gpio), GFP_KERNEL);
if (!clk_gpio)
return ERR_PTR(-ENOMEM);
if (active_low)
gpio_flags = GPIOF_ACTIVE_LOW | GPIOF_OUT_INIT_HIGH;
else
gpio_flags = GPIOF_OUT_INIT_LOW;
if (dev)
err = devm_gpio_request_one(dev, gpio, gpio_flags, name);
else
err = gpio_request_one(gpio, gpio_flags, name);
if (err) {
if (err != -EPROBE_DEFER)
pr_err("%s: %s: Error requesting clock control gpio %u\n",
__func__, name, gpio);
if (!dev)
kfree(clk_gpio);
return ERR_PTR(err);
}
init.name = name;
init.ops = clk_gpio_ops;
init.flags = flags | CLK_IS_BASIC;
init.parent_names = parent_names;
init.num_parents = num_parents;
clk_gpio->gpiod = gpio_to_desc(gpio);
clk_gpio->hw.init = &init;
if (dev)
clk = devm_clk_register(dev, &clk_gpio->hw);
else
clk = clk_register(NULL, &clk_gpio->hw);
if (!IS_ERR(clk))
return clk;
if (!dev) {
gpiod_put(clk_gpio->gpiod);
kfree(clk_gpio);
}
return clk;
}
/**
* clk_register_gpio_gate - register a gpio clock gate with the clock framework
* @dev: device that is registering this clock
* @name: name of this clock
* @parent_name: name of this clock's parent
* @gpio: gpio number to gate this clock
* @active_low: true if gpio should be set to 0 to enable clock
* @flags: clock flags
*/
struct clk *clk_register_gpio_gate(struct device *dev, const char *name,
const char *parent_name, unsigned gpio, bool active_low,
unsigned long flags)
{
return clk_register_gpio(dev, name,
(parent_name ? &parent_name : NULL),
(parent_name ? 1 : 0), gpio, active_low, flags,
&clk_gpio_gate_ops);
}
EXPORT_SYMBOL_GPL(clk_register_gpio_gate);
/**
* clk_register_gpio_mux - register a gpio clock mux with the clock framework
* @dev: device that is registering this clock
* @name: name of this clock
* @parent_names: names of this clock's parents
* @num_parents: number of parents listed in @parent_names
* @gpio: gpio number to gate this clock
* @active_low: true if gpio should be set to 0 to enable clock
* @flags: clock flags
*/
struct clk *clk_register_gpio_mux(struct device *dev, const char *name,
const char * const *parent_names, u8 num_parents, unsigned gpio,
bool active_low, unsigned long flags)
{
if (num_parents != 2) {
pr_err("mux-clock %s must have 2 parents\n", name);
return ERR_PTR(-EINVAL);
}
return clk_register_gpio(dev, name, parent_names, num_parents,
gpio, active_low, flags, &clk_gpio_mux_ops);
}
EXPORT_SYMBOL_GPL(clk_register_gpio_mux);
#ifdef CONFIG_OF
/**
* clk_register_get() has to be delayed, because -EPROBE_DEFER
* can not be handled properly at of_clk_init() call time.
*/
struct clk_gpio_delayed_register_data {
const char *gpio_name;
struct device_node *node;
struct mutex lock;
struct clk *clk;
struct clk *(*clk_register_get)(const char *name,
const char * const *parent_names, u8 num_parents,
unsigned gpio, bool active_low);
};
static struct clk *of_clk_gpio_delayed_register_get(
struct of_phandle_args *clkspec, void *_data)
{
struct clk_gpio_delayed_register_data *data = _data;
struct clk *clk;
const char **parent_names;
int i, num_parents;
int gpio;
enum of_gpio_flags of_flags;
mutex_lock(&data->lock);
if (data->clk) {
mutex_unlock(&data->lock);
return data->clk;
}
gpio = of_get_named_gpio_flags(data->node, data->gpio_name, 0,
&of_flags);
if (gpio < 0) {
mutex_unlock(&data->lock);
if (gpio == -EPROBE_DEFER)
pr_debug("%s: %s: GPIOs not yet available, retry later\n",
data->node->name, __func__);
else
pr_err("%s: %s: Can't get '%s' DT property\n",
data->node->name, __func__,
data->gpio_name);
return ERR_PTR(gpio);
}
num_parents = of_clk_get_parent_count(data->node);
parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL);
if (!parent_names) {
clk = ERR_PTR(-ENOMEM);
goto out;
}
for (i = 0; i < num_parents; i++)
parent_names[i] = of_clk_get_parent_name(data->node, i);
clk = data->clk_register_get(data->node->name, parent_names,
num_parents, gpio, of_flags & OF_GPIO_ACTIVE_LOW);
if (IS_ERR(clk))
goto out;
data->clk = clk;
out:
mutex_unlock(&data->lock);
kfree(parent_names);
return clk;
}
static struct clk *of_clk_gpio_gate_delayed_register_get(const char *name,
const char * const *parent_names, u8 num_parents,
unsigned gpio, bool active_low)
{
return clk_register_gpio_gate(NULL, name, parent_names[0],
gpio, active_low, 0);
}
static struct clk *of_clk_gpio_mux_delayed_register_get(const char *name,
const char * const *parent_names, u8 num_parents, unsigned gpio,
bool active_low)
{
return clk_register_gpio_mux(NULL, name, parent_names, num_parents,
gpio, active_low, 0);
}
static void __init of_gpio_clk_setup(struct device_node *node,
const char *gpio_name,
struct clk *(*clk_register_get)(const char *name,
const char * const *parent_names,
u8 num_parents,
unsigned gpio, bool active_low))
{
struct clk_gpio_delayed_register_data *data;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return;
data->node = node;
data->gpio_name = gpio_name;
data->clk_register_get = clk_register_get;
mutex_init(&data->lock);
of_clk_add_provider(node, of_clk_gpio_delayed_register_get, data);
}
static void __init of_gpio_gate_clk_setup(struct device_node *node)
{
of_gpio_clk_setup(node, "enable-gpios",
of_clk_gpio_gate_delayed_register_get);
}
CLK_OF_DECLARE(gpio_gate_clk, "gpio-gate-clock", of_gpio_gate_clk_setup);
void __init of_gpio_mux_clk_setup(struct device_node *node)
{
of_gpio_clk_setup(node, "select-gpios",
of_clk_gpio_mux_delayed_register_get);
}
CLK_OF_DECLARE(gpio_mux_clk, "gpio-mux-clock", of_gpio_mux_clk_setup);
#endif
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