spi.c

/*
 * SPI init/core code
 *
 * Copyright (C) 2005 David Brownell
 * Copyright (C) 2008 Secret Lab Technologies Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/slab.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#include <linux/of_gpio.h>
#include <linux/pm_runtime.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/kthread.h>

static void spidev_release(struct device *dev)
{
	struct spi_device	*spi = to_spi_device(dev);

	/* spi masters may cleanup for released devices */
	if (spi->master->cleanup)
		spi->master->cleanup(spi);

	spi_master_put(spi->master);
	kfree(spi);
}

static ssize_t
modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
	const struct spi_device	*spi = to_spi_device(dev);

	return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
}

static struct device_attribute spi_dev_attrs[] = {
	__ATTR_RO(modalias),
	__ATTR_NULL,
};

/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 * and the sysfs version makes coldplug work too.
 */

static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
						const struct spi_device *sdev)
{
	while (id->name[0]) {
		if (!strcmp(sdev->modalias, id->name))
			return id;
		id++;
	}
	return NULL;
}

const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
{
	const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);

	return spi_match_id(sdrv->id_table, sdev);
}
EXPORT_SYMBOL_GPL(spi_get_device_id);

static int spi_match_device(struct device *dev, struct device_driver *drv)
{
	const struct spi_device	*spi = to_spi_device(dev);
	const struct spi_driver	*sdrv = to_spi_driver(drv);

	/* Attempt an OF style match */
	if (of_driver_match_device(dev, drv))
		return 1;

	if (sdrv->id_table)
		return !!spi_match_id(sdrv->id_table, spi);

	return strcmp(spi->modalias, drv->name) == 0;
}

static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	const struct spi_device		*spi = to_spi_device(dev);

	add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int spi_legacy_suspend(struct device *dev, pm_message_t message)
{
	int			value = 0;
	struct spi_driver	*drv = to_spi_driver(dev->driver);

	/* suspend will stop irqs and dma; no more i/o */
	if (drv) {
		if (drv->suspend)
			value = drv->suspend(to_spi_device(dev), message);
		else
			dev_dbg(dev, "... can't suspend\n");
	}
	return value;
}

static int spi_legacy_resume(struct device *dev)
{
	int			value = 0;
	struct spi_driver	*drv = to_spi_driver(dev->driver);

	/* resume may restart the i/o queue */
	if (drv) {
		if (drv->resume)
			value = drv->resume(to_spi_device(dev));
		else
			dev_dbg(dev, "... can't resume\n");
	}
	return value;
}

static int spi_pm_suspend(struct device *dev)
{
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pm)
		return pm_generic_suspend(dev);
	else
		return spi_legacy_suspend(dev, PMSG_SUSPEND);
}

static int spi_pm_resume(struct device *dev)
{
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pm)
		return pm_generic_resume(dev);
	else
		return spi_legacy_resume(dev);
}

static int spi_pm_freeze(struct device *dev)
{
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pm)
		return pm_generic_freeze(dev);
	else
		return spi_legacy_suspend(dev, PMSG_FREEZE);
}

static int spi_pm_thaw(struct device *dev)
{
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pm)
		return pm_generic_thaw(dev);
	else
		return spi_legacy_resume(dev);
}

static int spi_pm_poweroff(struct device *dev)
{
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pm)
		return pm_generic_poweroff(dev);
	else
		return spi_legacy_suspend(dev, PMSG_HIBERNATE);
}

static int spi_pm_restore(struct device *dev)
{
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pm)
		return pm_generic_restore(dev);
	else
		return spi_legacy_resume(dev);
}