Commit 33d76291 authored by Vaibhav Hiremath's avatar Vaibhav Hiremath Committed by Greg Kroah-Hartman
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greybus: arche-apb-ctrl: Add sysfs to allow user to change state 



This patch introduces sysfs interface for the user space to enable
state change of the driver. Driver supports below operational
states,

 - off
 - active
 - standby
 - fw_flashing

To see the current state

i # cat /sys/devices/arche_platform.*/apb*/state

And to change the state
 # echo [off/active/standby/fw_flashing] > /sys/devices/arche_platform.*/apb*/state

Testing Done: Tested on EVT1.2 and DB3.5 platform

Signed-off-by: default avatarVaibhav Hiremath <vaibhav.hiremath@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 6961e046

drivers/staging/greybus/arche-apb-ctrl.c

+115 −0
Original line number Diff line number Diff line
@@ -113,6 +113,52 @@ static int apb_ctrl_coldboot_seq(struct platform_device *pdev) 
	return 0;

}



static int apb_ctrl_fw_flashing_seq(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);

	int ret;



	ret = regulator_enable(apb->vcore);

	if (ret) {

		dev_err(dev, "failed to enable core regulator\n");

		return ret;

	}



	ret = regulator_enable(apb->vio);

	if (ret) {

		dev_err(dev, "failed to enable IO regulator\n");

		return ret;

	}



	/* for flashing device should be in reset state */

	assert_reset(apb->resetn_gpio);

	apb->state = ARCHE_PLATFORM_STATE_FW_FLASHING;



	return 0;

}



static int apb_ctrl_standby_boot_seq(struct platform_device *pdev)

{

	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);



	/* If it is in OFF state, then we do not want to change the state */

	if (apb->state == ARCHE_PLATFORM_STATE_OFF)

		return 0;



	/*

	 * As per WDM spec, do nothing

	 *

	 * Pasted from WDM spec,

	 *  - A falling edge on POWEROFF_L is detected (a)

	 *  - WDM enters standby mode, but no output signals are changed

	 * */



	/* TODO: POWEROFF_L is input to WDM module  */

	apb->state = ARCHE_PLATFORM_STATE_STANDBY;

	return 0;

}



static void apb_ctrl_poweroff_seq(struct platform_device *pdev)

{

	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
@@ -134,6 +180,66 @@ static void apb_ctrl_poweroff_seq(struct platform_device *pdev) 
	/* TODO: May have to send an event to SVC about this exit */

}



static ssize_t state_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t count)

{

	struct platform_device *pdev = to_platform_device(dev);

	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);

	int ret = 0;



	if (sysfs_streq(buf, "off")) {

		if (apb->state == ARCHE_PLATFORM_STATE_OFF)

			return count;



		apb_ctrl_poweroff_seq(pdev);

	} else if (sysfs_streq(buf, "active")) {

		if (apb->state == ARCHE_PLATFORM_STATE_ACTIVE)

			return count;



		apb_ctrl_poweroff_seq(pdev);

		ret = apb_ctrl_coldboot_seq(pdev);

	} else if (sysfs_streq(buf, "standby")) {

		if (apb->state == ARCHE_PLATFORM_STATE_STANDBY)

			return count;



		ret = apb_ctrl_standby_boot_seq(pdev);

	} else if (sysfs_streq(buf, "fw_flashing")) {

		if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)

			return count;



		/* First we want to make sure we power off everything

		 * and then enter FW flashing state */

		apb_ctrl_poweroff_seq(pdev);

		ret = apb_ctrl_fw_flashing_seq(pdev);

	} else {

		dev_err(dev, "unknown state\n");

		ret = -EINVAL;

	}



	return ret ? ret : count;

}



static ssize_t state_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);



	switch (apb->state) {

	case ARCHE_PLATFORM_STATE_OFF:

		return sprintf(buf, "off\n");

	case ARCHE_PLATFORM_STATE_ACTIVE:

		return sprintf(buf, "active\n");

	case ARCHE_PLATFORM_STATE_STANDBY:

		return sprintf(buf, "standby\n");

	case ARCHE_PLATFORM_STATE_FW_FLASHING:

		return sprintf(buf, "fw_flashing\n");

	default:

		return sprintf(buf, "unknown state\n");

	}

}



static DEVICE_ATTR_RW(state);



static int apb_ctrl_get_devtree_data(struct platform_device *pdev,

		struct arche_apb_ctrl_drvdata *apb)

{
@@ -243,10 +349,18 @@ int arche_apb_ctrl_probe(struct platform_device *pdev) 


	platform_set_drvdata(pdev, apb);



	/* Create sysfs interface to allow user to change state dynamically */

	ret = device_create_file(dev, &dev_attr_state);

	if (ret) {

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

		return ret;

	}



	ret = apb_ctrl_coldboot_seq(pdev);

	if (ret) {

		dev_err(dev, "failed to set init state of control signal %d\n",

				ret);

		device_remove_file(dev, &dev_attr_state);

		platform_set_drvdata(pdev, NULL);

		return ret;

	}
@@ -261,6 +375,7 @@ int arche_apb_ctrl_remove(struct platform_device *pdev) 
{

	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);



	device_remove_file(&pdev->dev, &dev_attr_state);

	apb_ctrl_poweroff_seq(pdev);

	platform_set_drvdata(pdev, NULL);

	unexport_gpios(apb);