fwupd/libfwupdplugin/fu-i2c-device.c

/*
 * Copyright (C) 2021 Richard Hughes <richard@hughsie.com>
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#define G_LOG_DOMAIN "FuI2cDevice"

#include "config.h"

#include <fcntl.h>
#include <glib/gstdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif

#include "fu-i2c-device.h"
#include "fu-string.h"

/**
 * FuI2cDevice
 *
 * A I²C device with an assigned bus number.
 *
 * See also: #FuUdevDevice
 */

typedef struct {
	guint bus_number;
} FuI2cDevicePrivate;

G_DEFINE_TYPE_WITH_PRIVATE(FuI2cDevice, fu_i2c_device, FU_TYPE_UDEV_DEVICE)

enum { PROP_0, PROP_BUS_NUMBER, PROP_LAST };

#define GET_PRIVATE(o) (fu_i2c_device_get_instance_private(o))

static void
fu_i2c_device_to_string(FuDevice *device, guint idt, GString *str)
{
	FuI2cDevice *self = FU_I2C_DEVICE(device);
	FuI2cDevicePrivate *priv = GET_PRIVATE(self);
	fu_string_append_kx(str, idt, "BusNumber", priv->bus_number);
}

static void
fu_i2c_device_get_property(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
	FuI2cDevice *self = FU_I2C_DEVICE(object);
	FuI2cDevicePrivate *priv = GET_PRIVATE(self);
	switch (prop_id) {
	case PROP_BUS_NUMBER:
		g_value_set_uint(value, priv->bus_number);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
		break;
	}
}

static void
fu_i2c_device_set_property(GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
{
	FuI2cDevice *self = FU_I2C_DEVICE(object);
	FuI2cDevicePrivate *priv = GET_PRIVATE(self);
	switch (prop_id) {
	case PROP_BUS_NUMBER:
		priv->bus_number = g_value_get_uint(value);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
		break;
	}
}

static gboolean
fu_i2c_device_open(FuDevice *device, GError **error)
{
#ifdef HAVE_GUDEV
	FuI2cDevice *self = FU_I2C_DEVICE(device);
	FuI2cDevicePrivate *priv = GET_PRIVATE(self);
	gint bus_fd;
	g_autofree gchar *bus_path = NULL;

	/* open the bus, not the device represented by self */
	bus_path = g_strdup_printf("/dev/i2c-%u", priv->bus_number);
	if ((bus_fd = g_open(bus_path, O_RDWR, 0)) == -1) {
		g_set_error(error,
			    G_IO_ERROR,
#ifdef HAVE_ERRNO_H
			    g_io_error_from_errno(errno),
#else
			    G_IO_ERROR_FAILED,
#endif
			    "failed to open %s read-write",
			    bus_path);
		return FALSE;
	}
	fu_udev_device_set_fd(FU_UDEV_DEVICE(self), bus_fd);
	fu_udev_device_set_flags(FU_UDEV_DEVICE(self), FU_UDEV_DEVICE_FLAG_NONE);
#endif

	/* FuUdevDevice->open */
	return FU_DEVICE_CLASS(fu_i2c_device_parent_class)->open(device, error);
}

static gboolean
fu_i2c_device_probe(FuDevice *device, GError **error)
{
#ifdef HAVE_GUDEV
	FuI2cDevice *self = FU_I2C_DEVICE(device);
	FuI2cDevicePrivate *priv = GET_PRIVATE(self);
	GUdevDevice *udev_device = fu_udev_device_get_dev(FU_UDEV_DEVICE(device));
	const gchar *tmp;
	g_autoptr(GMatchInfo) info = NULL;
	g_autoptr(GRegex) regex = NULL;
#endif

	/* set physical ID */
	if (!fu_udev_device_set_physical_id(FU_UDEV_DEVICE(device), "i2c", error))
		return FALSE;

#ifdef HAVE_GUDEV
	/* i2c devices all expose a name */
	tmp = g_udev_device_get_sysfs_attr(udev_device, "name");
	fu_device_add_instance_strsafe(device, "NAME", tmp);
	if (!fu_device_build_instance_id(device, error, "I2C", "NAME", NULL))
		return FALSE;

	/* get bus number out of sysfs path */
	regex = g_regex_new("/i2c-([0-9]+)/", 0, 0, error);
	if (regex == NULL)
		return FALSE;
	tmp = g_udev_device_get_sysfs_path(udev_device);
	if (!g_regex_match_full(regex, tmp, -1, 0, 0, &info, error))
		return FALSE;
	priv->bus_number = g_ascii_strtoll(g_match_info_fetch(info, 1), NULL, 10);
#endif

	/* success */
	return TRUE;
}

/**
 * fu_i2c_device_get_bus_number:
 * @self: a #FuI2cDevice
 *
 * Gets the I²C bus number.
 *
 * Returns: integer
 *
 * Since: 1.6.1
 **/
guint
fu_i2c_device_get_bus_number(FuI2cDevice *self)
{
	FuI2cDevicePrivate *priv = GET_PRIVATE(self);
	g_return_val_if_fail(FU_IS_I2C_DEVICE(self), G_MAXUINT);
	return priv->bus_number;
}

/**
 * fu_i2c_device_set_bus_number:
 * @self: a #FuI2cDevice
 * @bus_number: integer, typically the output of g_udev_device_get_number()
 *
 * Sets the I²C bus number.
 *
 * Since: 1.6.2
 **/
void
fu_i2c_device_set_bus_number(FuI2cDevice *self, guint bus_number)
{
	FuI2cDevicePrivate *priv = GET_PRIVATE(self);
	g_return_if_fail(FU_IS_I2C_DEVICE(self));
	priv->bus_number = bus_number;
}

/**
 * fu_i2c_device_write:
 * @self: a #FuI2cDevice
 * @buf: (out): data
 * @bufsz: size of @data
 * @error: (nullable): optional return location for an error
 *
 * Write multiple bytes to the I²C device.
 *
 * Returns: %TRUE for success
 *
 * Since: 1.8.2
 **/
gboolean
fu_i2c_device_write(FuI2cDevice *self, const guint8 *buf, gsize bufsz, GError **error)
{
	return fu_udev_device_pwrite(FU_UDEV_DEVICE(self), 0x0, buf, bufsz, error);
}

/**
 * fu_i2c_device_read:
 * @self: a #FuI2cDevice
 * @buf: (out): data
 * @bufsz: size of @data
 * @error: (nullable): optional return location for an error
 *
 * Read multiple bytes from the I²C device.
 *
 * Returns: %TRUE for success
 *
 * Since: 1.8.2
 **/
gboolean
fu_i2c_device_read(FuI2cDevice *self, guint8 *buf, gsize bufsz, GError **error)
{
	return fu_udev_device_pread(FU_UDEV_DEVICE(self), 0x0, buf, bufsz, error);
}

static void
fu_i2c_device_init(FuI2cDevice *self)
{
}

static void
fu_i2c_device_class_init(FuI2cDeviceClass *klass)
{
	FuDeviceClass *klass_device = FU_DEVICE_CLASS(klass);
	GObjectClass *object_class = G_OBJECT_CLASS(klass);
	GParamSpec *pspec;

	object_class->get_property = fu_i2c_device_get_property;
	object_class->set_property = fu_i2c_device_set_property;
	klass_device->open = fu_i2c_device_open;
	klass_device->probe = fu_i2c_device_probe;
	klass_device->to_string = fu_i2c_device_to_string;

	/**
	 * FuI2cDevice:bus-number:
	 *
	 * The I²C bus number.
	 *
	 * Since: 1.6.2
	 */
	pspec = g_param_spec_uint("bus-number",
				  NULL,
				  NULL,
				  0x0,
				  G_MAXUINT,
				  0x0,
				  G_PARAM_READWRITE | G_PARAM_STATIC_NAME);
	g_object_class_install_property(object_class, PROP_BUS_NUMBER, pspec);
}