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clk: clk-gpio: add support for sleeping GPIOs in gpio-gate-clk 

The current implementation of gpio-gate-clk enables/disables the clock
using the GPIO in the ->enable() and ->disable() clock callbacks. This
requires the GPIO to be configurable in atomic contexts. While it is
the case for most memory-mapped GPIO controllers, it is not the case
for GPIO expanders on I2C or SPI.

This commit extends the gpio-gate-clk to check whether the GPIO calls
require sleeping or not. If sleeping is not required, the current
implementation based on ->enable()/->disable() is kept. However, if
sleeping is needed, we instead implement the logic in the ->prepare()
and ->unprepare() hooks. Thanks to this, a gate clock connected to a
GPIO on a GPIO expander can be controlled with the existing driver.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[sboyd@kernel.org: Mark clk ops static]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Thomas Petazzoni 2019-02-11 14:58:18 +01:00 committed by Stephen Boyd
parent bfeffd1552
commit c0189feead
1 changed files with 37 additions and 2 deletions
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39
drivers/clk/clk-gpio.c
View File

@ -58,6 +58,35 @@ const struct clk_ops clk_gpio_gate_ops = {
};
EXPORT_SYMBOL_GPL(clk_gpio_gate_ops);
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:
@ -144,10 +173,16 @@ struct clk_hw *clk_hw_register_gpio_gate(struct device *dev, const char *name,
const char *parent_name, struct gpio_desc *gpiod,
unsigned long flags)
{
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, name,
(parent_name ? &parent_name : NULL),
(parent_name ? 1 : 0), gpiod, flags,
&clk_gpio_gate_ops);
(parent_name ? 1 : 0), gpiod, flags, ops);
}
EXPORT_SYMBOL_GPL(clk_hw_register_gpio_gate);