path: root/drivers/staging/greybus/arche-platform.c

/*
 * Arche Platform driver to enable Unipro link.
 *
 * Copyright 2014-2015 Google Inc.
 * Copyright 2014-2015 Linaro Ltd.
 *
 * Released under the GPLv2 only.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/of_platform.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include "arche_platform.h"

#include <linux/usb/usb3613.h>

enum svc_wakedetect_state {
	WD_STATE_IDLE,			/* Default state = pulled high/low */
	WD_STATE_BOOT_INIT,		/* WD = falling edge (low) */
	WD_STATE_COLDBOOT_TRIG,		/* WD = rising edge (high), > 30msec */
	WD_STATE_STANDBYBOOT_TRIG,	/* As of now not used ?? */
	WD_STATE_COLDBOOT_START,	/* Cold boot process started */
	WD_STATE_STANDBYBOOT_START,	/* Not used */
};

struct arche_platform_drvdata {
	/* Control GPIO signals to and from AP <=> SVC */
	int svc_reset_gpio;
	bool is_reset_act_hi;
	int svc_sysboot_gpio;
	int wake_detect_gpio; /* bi-dir,maps to WAKE_MOD & WAKE_FRAME signals */

	enum arche_platform_state state;

	unsigned int svc_refclk_req;
	struct clk *svc_ref_clk;

	struct pinctrl *pinctrl;
	struct pinctrl_state *pin_default;

	int num_apbs;

	struct delayed_work delayed_work;
	enum svc_wakedetect_state wake_detect_state;

	struct device *dev;
};

static inline void svc_reset_onoff(unsigned int gpio, bool onoff)
{
	gpio_set_value(gpio, onoff);
}

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

	ret = apb_ctrl_fw_flashing(dev);
	if (ret)
		dev_warn(dev, "failed to switch to fw flashing state\n");

	/*Child nodes are independent, so do not exit coldboot operation */
	return 0;
}

static int apb_poweroff(struct device *dev, void *data)
{
	apb_ctrl_poweroff(dev);

	return 0;
}

/**
 * hub_conf_delayed_work - Configures USB3613 device to HUB mode
 *
 * The idea here is to split the APB coldboot operation with slow HUB configuration,
 * so that driver response to wake/detect event can be met.
 * So expectation is, once code reaches here, means initial unipro linkup
 * between APB<->Switch was successful, so now just take it to AP.
 */
static void hub_conf_delayed_work(struct work_struct *work)
{
	struct arche_platform_drvdata *arche_pdata =
		container_of(work, struct arche_platform_drvdata, delayed_work.work);

	/* Enable HUB3613 into HUB mode. */
	if (usb3613_hub_mode_ctrl(true))
		dev_warn(arche_pdata->dev, "failed to control hub device\n");
}

static int arche_platform_coldboot_seq(struct arche_platform_drvdata *arche_pdata)
{
	int ret;

	if (arche_pdata->state == ARCHE_PLATFORM_STATE_ACTIVE)
		return 0;

	dev_info(arche_pdata->dev, "Booting from cold boot state\n");

	svc_reset_onoff(arche_pdata->svc_reset_gpio,
			arche_pdata->is_reset_act_hi);

	gpio_set_value(arche_pdata->svc_sysboot_gpio, 0);
	usleep_range(100, 200);

	ret = clk_prepare_enable(arche_pdata->svc_ref_clk);
	if (ret) {
		dev_err(arche_pdata->dev, "failed to enable svc_ref_clk: %d\n",
				ret);
		return ret;
	}

	/* bring SVC out of reset */
	svc_reset_onoff(arche_pdata->svc_reset_gpio,
			!arche_pdata->is_reset_act_hi);

	arche_pdata->state = ARCHE_PLATFORM_STATE_ACTIVE;

	return 0;
}

static void arche_platform_fw_flashing_seq(struct arche_platform_drvdata *arche_pdata)
{
	if (arche_pdata->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
		return;

	dev_info(arche_pdata->dev, "Switching to FW flashing state\n");

	svc_reset_onoff(arche_pdata->svc_reset_gpio,
			arche_pdata->is_reset_act_hi);

	gpio_set_value(arche_pdata->svc_sysboot_gpio, 1);

	usleep_range(100, 200);
	svc_reset_onoff(arche_pdata->svc_reset_gpio,
			!arche_pdata->is_reset_act_hi);

	arche_pdata->state = ARCHE_PLATFORM_STATE_FW_FLASHING;

}

static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pdata)
{
	if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)
		return;

	/* If in fw_flashing mode, then no need to repeate things again */
	if (arche_pdata->state != ARCHE_PLATFORM_STATE_FW_FLASHING) {
		/* Send disconnect/detach event to SVC */
		gpio_set_value(arche_pdata->wake_detect_gpio, 0);
		usleep_range(100, 200);
		arche_pdata->wake_detect_state = WD_STATE_IDLE;

		clk_disable_unprepare(arche_pdata->svc_ref_clk);
	}

	/* As part of exit, put APB back in reset state */
	svc_reset_onoff(arche_pdata->svc_reset_gpio,
			arche_pdata->is_reset_act_hi);

	arche_pdata->state = ARCHE_PLATFORM_STATE_OFF;
}

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_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
	int ret = 0;

	if (sysfs_streq(buf, "off")) {
		if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)
			return count;

		/*  If SVC goes down, bring down APB's as well */
		device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);

		arche_platform_poweroff_seq(arche_pdata);

		ret = usb3613_hub_mode_ctrl(false);
		if (ret)
			dev_warn(arche_pdata->dev, "failed to control hub device\n");
			/* TODO: Should we do anything more here ?? */
	} else if (sysfs_streq(buf, "active")) {
		if (arche_pdata->state == ARCHE_PLATFORM_STATE_ACTIVE)
			return count;

		ret = arche_platform_coldboot_seq(arche_pdata);
	} else if (sysfs_streq(buf, "standby")) {
		if (arche_pdata->state == ARCHE_PLATFORM_STATE_STANDBY)
			return count;

		dev_warn(arche_pdata->dev, "standby state not supported\n");
	} else if (sysfs_streq(buf, "fw_flashing")) {
		if (arche_pdata->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
			return count;

		/* First we want to make sure we power off everything
		 * and then enter FW flashing state */
		device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);

		arche_platform_poweroff_seq(arche_pdata);

		ret = usb3613_hub_mode_ctrl(false);
		if (ret)
			dev_warn(arche_pdata->dev, "failed to control hub device\n");
			/* TODO: Should we do anything more here ?? */

		arche_platform_fw_flashing_seq(arche_pdata);

		device_for_each_child(arche_pdata->dev, NULL, apb_fw_flashing_state);
	} else {
		dev_err(arche_pdata->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_platform_drvdata *arche_pdata = dev_get_drvdata(dev);

	switch (arche_pdata->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 arche_platform_probe(struct platform_device *pdev)
{
	struct arche_platform_drvdata *arche_pdata;
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	int ret;

	arche_pdata = devm_kzalloc(&pdev->dev, sizeof(*arche_pdata), GFP_KERNEL);
	if (!arche_pdata)
		return -ENOMEM;

	/* setup svc reset gpio */
	arche_pdata->is_reset_act_hi = of_property_read_bool(np,
					"svc,reset-active-high");
	arche_pdata->svc_reset_gpio = of_get_named_gpio(np, "svc,reset-gpio", 0);
	if (arche_pdata->svc_reset_gpio < 0) {
		dev_err(dev, "failed to get reset-gpio\n");