Re: [PATCH v3 3/3] soundwire: qcom: add in-band wake up interrupt support

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 2/28/22 11:25, Srinivas Kandagatla wrote:
> Some of the Qualcomm SoundWire Controller instances like the ones that are
> connected to RX path along with Headset connections support Waking up
> Controller from Low power clock stop state using SoundWire In-band interrupt.
> SoundWire Slave on the bus would initiate this by pulling the data line high,
> while the clock is stopped.
> 
> Add support to this wake up interrupt.
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

> ---
>  drivers/soundwire/qcom.c | 50 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> index 810232686196..e893aee1b057 100644
> --- a/drivers/soundwire/qcom.c
> +++ b/drivers/soundwire/qcom.c
> @@ -14,6 +14,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/regmap.h>
>  #include <linux/slab.h>
> +#include <linux/pm_wakeirq.h>
>  #include <linux/slimbus.h>
>  #include <linux/soundwire/sdw.h>
>  #include <linux/soundwire/sdw_registers.h>
> @@ -154,6 +155,7 @@ struct qcom_swrm_ctrl {
>  	u8 rd_cmd_id;
>  	int irq;
>  	unsigned int version;
> +	int wake_irq;
>  	int num_din_ports;
>  	int num_dout_ports;
>  	int cols_index;
> @@ -503,6 +505,31 @@ static int qcom_swrm_enumerate(struct sdw_bus *bus)
>  	return 0;
>  }
>  
> +static irqreturn_t qcom_swrm_wake_irq_handler(int irq, void *dev_id)
> +{
> +	struct qcom_swrm_ctrl *swrm = dev_id;
> +	int ret;
> +
> +	ret = pm_runtime_get_sync(swrm->dev);
> +	if (ret < 0 && ret != -EACCES) {
> +		dev_err_ratelimited(swrm->dev,
> +				    "pm_runtime_get_sync failed in %s, ret %d\n",
> +				    __func__, ret);
> +		pm_runtime_put_noidle(swrm->dev);
> +	}
> +
> +	if (swrm->wake_irq > 0) {
> +		if (!irqd_irq_disabled(irq_get_irq_data(swrm->wake_irq)))
> +			disable_irq_nosync(swrm->wake_irq);
> +	}
> +
> +	pm_runtime_mark_last_busy(swrm->dev);
> +	pm_runtime_put_autosuspend(swrm->dev);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +
>  static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
>  {
>  	struct qcom_swrm_ctrl *swrm = dev_id;
> @@ -1340,6 +1367,19 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>  		goto err_clk;
>  	}
>  
> +	ctrl->wake_irq = of_irq_get(dev->of_node, 1);
> +	if (ctrl->wake_irq > 0) {
> +		ret = devm_request_threaded_irq(dev, ctrl->wake_irq, NULL,
> +						qcom_swrm_wake_irq_handler,
> +						IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> +						"swr_wake_irq", ctrl);
> +		if (ret) {
> +			dev_err(dev, "Failed to request soundwire wake irq\n");
> +			goto err_init;
> +		}
> +	}
> +
> +
>  	ret = sdw_bus_master_add(&ctrl->bus, dev, dev->fwnode);
>  	if (ret) {
>  		dev_err(dev, "Failed to register Soundwire controller (%d)\n",
> @@ -1424,6 +1464,11 @@ static int swrm_runtime_resume(struct device *dev)
>  	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
>  	int ret;
>  
> +	if (ctrl->wake_irq > 0) {
> +		if (!irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq)))
> +			disable_irq_nosync(ctrl->wake_irq);
> +	}
> +
>  	clk_prepare_enable(ctrl->hclk);
>  
>  	if (ctrl->clock_stop_not_supported) {
> @@ -1491,6 +1536,11 @@ static int __maybe_unused swrm_runtime_suspend(struct device *dev)
>  
>  	usleep_range(300, 305);
>  
> +	if (ctrl->wake_irq > 0) {
> +		if (irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq)))
> +			enable_irq(ctrl->wake_irq);
> +	}
> +
>  	return 0;
>  }
>