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Commit f760bbfb authored by Vaibhav Hiremath's avatar Vaibhav Hiremath Committed by Greg Kroah-Hartman
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greybus: arche-platform: Enable interrupt support on wake/detect line 



This patch enabled interrupt support on events received over wake/detect
line. The driver follows below state machine,

Default: wake/detect line is high (WD_STATE_IDLE)
On Falling edge:
  SVC initiates boot (either cold/standby).
  On ES3, > 30msec = coldboot, else standby boot.
  Driver moves to WD_STATE_BOOT_INIT
On rising edge (> 30msec):
  SVC expects APB to coldboot
  Driver wakes irq thread which kicks off APB  coldboot
  (WD_STATE_COLDBOOT_TRIG)
On rising edge (< 30msec):
  Driver ignores it, do nothing.

After coldboot of APB, HUB configuration work is scheduled after 2 sec,
allowing enough time for APB<->SVC/Switch to linkup (in multiple
iterations)

Testing Done: Tested on DB3.5 platform.

Signed-off-by: default avatarVaibhav Hiremath <vaibhav.hiremath@linaro.org>
Reviewed-by: default avatarMichael Scott <michael.scott@linaro.org>
Tested-by: default avatarMichael Scott <michael.scott@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 685353c1

drivers/staging/greybus/arche-platform.c

+120 −0
Original line number Diff line number Diff line
@@ -17,10 +17,15 @@ 
#include <linux/pinctrl/consumer.h>

#include <linux/platform_device.h>

#include <linux/pm.h>

#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/time.h>

#include "arche_platform.h"



#include <linux/usb/usb3613.h>



#define WD_COLDBOOT_PULSE_WIDTH_MS	30



enum svc_wakedetect_state {

	WD_STATE_IDLE,			/* Default state = pulled high/low */

	WD_STATE_BOOT_INIT,		/* WD = falling edge (low) */
@@ -49,6 +54,9 @@ struct arche_platform_drvdata { 


	struct delayed_work delayed_work;

	enum svc_wakedetect_state wake_detect_state;

	int wake_detect_irq;

	spinlock_t lock;

	unsigned long wake_detect_start;



	struct device *dev;

};
@@ -58,6 +66,18 @@ static inline void svc_reset_onoff(unsigned int gpio, bool onoff) 
	gpio_set_value(gpio, onoff);

}



static int apb_cold_boot(struct device *dev, void *data)

{

	int ret;



	ret = apb_ctrl_coldboot(dev);

	if (ret)

		dev_warn(dev, "failed to coldboot\n");



	/*Child nodes are independent, so do not exit coldboot operation */

	return 0;

}



static int apb_fw_flashing_state(struct device *dev, void *data)

{

	int ret;
@@ -95,6 +115,86 @@ static void hub_conf_delayed_work(struct work_struct *work) 
		dev_warn(arche_pdata->dev, "failed to control hub device\n");

}



static irqreturn_t arche_platform_wd_irq_thread(int irq, void *devid)

{

	struct arche_platform_drvdata *arche_pdata = devid;

	unsigned long flags;



	spin_lock_irqsave(&arche_pdata->lock, flags);

	if (arche_pdata->wake_detect_state != WD_STATE_COLDBOOT_TRIG) {

		/* Something is wrong */

		spin_unlock_irqrestore(&arche_pdata->lock, flags);

		return IRQ_HANDLED;

	}



	arche_pdata->wake_detect_state = WD_STATE_COLDBOOT_START;

	spin_unlock_irqrestore(&arche_pdata->lock, flags);



	/* Bring APB out of reset: cold boot sequence */

	device_for_each_child(arche_pdata->dev, NULL, apb_cold_boot);



	spin_lock_irqsave(&arche_pdata->lock, flags);

	/* USB HUB configuration */

	schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));

	arche_pdata->wake_detect_state = WD_STATE_IDLE;

	spin_unlock_irqrestore(&arche_pdata->lock, flags);



	return IRQ_HANDLED;

}



static irqreturn_t arche_platform_wd_irq(int irq, void *devid)

{

	struct arche_platform_drvdata *arche_pdata = devid;

	unsigned long flags;



	spin_lock_irqsave(&arche_pdata->lock, flags);



	if (gpio_get_value(arche_pdata->wake_detect_gpio)) {

		/* wake/detect rising */



		/*

		 * If wake/detect line goes high after low, within less than

		 * 30msec, then standby boot sequence is initiated, which is not

		 * supported/implemented as of now. So ignore it.

		 */

		if (arche_pdata->wake_detect_state == WD_STATE_BOOT_INIT) {

			if (time_before(jiffies,

					arche_pdata->wake_detect_start +

					msecs_to_jiffies(WD_COLDBOOT_PULSE_WIDTH_MS))) {

				/* No harm with cancellation, even if not pending */

				cancel_delayed_work(&arche_pdata->delayed_work);

				arche_pdata->wake_detect_state = WD_STATE_IDLE;

			} else {

				/* Check we are not in middle of irq thread already */

				if (arche_pdata->wake_detect_state !=

						WD_STATE_COLDBOOT_START) {

					arche_pdata->wake_detect_state =

						WD_STATE_COLDBOOT_TRIG;

					spin_unlock_irqrestore(&arche_pdata->lock, flags);

					return IRQ_WAKE_THREAD;

				}

			}

		}

	} else {

		/* wake/detect falling */

		if (arche_pdata->wake_detect_state == WD_STATE_IDLE) {

			arche_pdata->wake_detect_start = jiffies;

			/* No harm with cancellation even if it is not pending*/

			cancel_delayed_work(&arche_pdata->delayed_work);

			/*

			 * In the begining, when wake/detect goes low (first time), we assume

			 * it is meant for coldboot and set the flag. If wake/detect line stays low

			 * beyond 30msec, then it is coldboot else fallback to standby boot.

			 */

			arche_pdata->wake_detect_state = WD_STATE_BOOT_INIT;

		}

	}



	spin_unlock_irqrestore(&arche_pdata->lock, flags);



	return IRQ_HANDLED;

}



static int arche_platform_coldboot_seq(struct arche_platform_drvdata *arche_pdata)

{

	int ret;
@@ -148,6 +248,8 @@ static void arche_platform_fw_flashing_seq(struct arche_platform_drvdata *arche_ 


static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pdata)

{

	unsigned long flags;



	if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)

		return;
@@ -156,7 +258,9 @@ static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pda 
		/* Send disconnect/detach event to SVC */

		gpio_set_value(arche_pdata->wake_detect_gpio, 0);

		usleep_range(100, 200);

		spin_lock_irqsave(&arche_pdata->lock, flags);

		arche_pdata->wake_detect_state = WD_STATE_IDLE;

		spin_unlock_irqrestore(&arche_pdata->lock, flags);



		clk_disable_unprepare(arche_pdata->svc_ref_clk);

	}
@@ -344,6 +448,22 @@ static int arche_platform_probe(struct platform_device *pdev) 


	arche_pdata->dev = &pdev->dev;



	spin_lock_init(&arche_pdata->lock);

	arche_pdata->wake_detect_irq =

		gpio_to_irq(arche_pdata->wake_detect_gpio);



	ret = devm_request_threaded_irq(dev, arche_pdata->wake_detect_irq,

			arche_platform_wd_irq,

			arche_platform_wd_irq_thread,

			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING | IRQF_ONESHOT,

			dev_name(dev), arche_pdata);

	if (ret) {

		dev_err(dev, "failed to request wake detect IRQ %d\n", ret);

		return ret;

	}

	/* Enable it only after  sending wake/detect event */

	disable_irq(arche_pdata->wake_detect_irq);



	ret = device_create_file(dev, &dev_attr_state);

	if (ret) {

		dev_err(dev, "failed to create state file in sysfs\n");