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 <[email protected]> --- drivers/clk/clk-gpio.c | 39 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 37 insertions(+), 2 deletions(-) diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c index 6a43ce420492..f5d481713c7d 100644 --- a/drivers/clk/clk-gpio.c +++ b/drivers/clk/clk-gpio.c @@ -61,6 +61,35 @@ 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); +} + +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: @@ -147,10 +176,16 @@ 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); -- 2.20.1
