toshiba_acpi: Add IIO interface for accelerometer axis data

This patch adds the accelerometer axis data to the IIO subsystem.

Currently reporting the X, Y and Z values, as no other data can be
queried given the fact that the accelerometer chip itself is hidden
behind the Toshiba proprietary interface.
Signed-off-by: Azael Avalos <coproscefalo@gmail.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

drivers/platform/x86/Kconfig

@@ -669,6 +669,7 @@ config ACPI_TOSHIBA
 	depends on SERIO_I8042 || SERIO_I8042 = n
 	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on RFKILL || RFKILL = n
+	depends on IIO
 	select INPUT_POLLDEV
 	select INPUT_SPARSEKMAP
 	---help---

drivers/platform/x86/toshiba_acpi.c

@@ -53,6 +53,7 @@
 #include <linux/uaccess.h>
 #include <linux/miscdevice.h>
 #include <linux/rfkill.h>
+#include <linux/iio/iio.h>
 #include <linux/toshiba.h>
 #include <acpi/video.h>
 
@@ -134,6 +135,7 @@ MODULE_LICENSE("GPL");
 
 /* Field definitions */
 #define HCI_ACCEL_MASK			0x7fff
+#define HCI_ACCEL_DIRECTION_MASK	0x8000
 #define HCI_HOTKEY_DISABLE		0x0b
 #define HCI_HOTKEY_ENABLE		0x09
 #define HCI_HOTKEY_SPECIAL_FUNCTIONS	0x10
@@ -178,6 +180,7 @@ struct toshiba_acpi_dev {
 	struct led_classdev eco_led;
 	struct miscdevice miscdev;
 	struct rfkill *wwan_rfk;
+	struct iio_dev *indio_dev;
 
 	int force_fan;
 	int last_key_event;
@@ -2419,6 +2422,81 @@ static void toshiba_acpi_kbd_bl_work(struct work_struct *work)
 					0x92, 0);
 }
 
+/*
+ * IIO device
+ */
+
+enum toshiba_iio_accel_chan {
+	AXIS_X,
+	AXIS_Y,
+	AXIS_Z
+};
+
+static int toshiba_iio_accel_get_axis(enum toshiba_iio_accel_chan chan)
+{
+	u32 xyval, zval;
+	int ret;
+
+	ret = toshiba_accelerometer_get(toshiba_acpi, &xyval, &zval);
+	if (ret < 0)
+		return ret;
+
+	switch (chan) {
+	case AXIS_X:
+		return xyval & HCI_ACCEL_DIRECTION_MASK ?
+			-(xyval & HCI_ACCEL_MASK) : xyval & HCI_ACCEL_MASK;
+	case AXIS_Y:
+		return (xyval >> HCI_MISC_SHIFT) & HCI_ACCEL_DIRECTION_MASK ?
+			-((xyval >> HCI_MISC_SHIFT) & HCI_ACCEL_MASK) :
+			(xyval >> HCI_MISC_SHIFT) & HCI_ACCEL_MASK;
+	case AXIS_Z:
+		return zval & HCI_ACCEL_DIRECTION_MASK ?
+			-(zval & HCI_ACCEL_MASK) : zval & HCI_ACCEL_MASK;
+	}
+
+	return ret;
+}
+
+static int toshiba_iio_accel_read_raw(struct iio_dev *indio_dev,
+				      struct iio_chan_spec const *chan,
+				      int *val, int *val2, long mask)
+{
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = toshiba_iio_accel_get_axis(chan->channel);
+		if (ret == -EIO || ret == -ENODEV)
+			return ret;
+
+		*val = ret;
+
+		return IIO_VAL_INT;
+	}
+
+	return -EINVAL;
+}
+
+#define TOSHIBA_IIO_ACCEL_CHANNEL(axis, chan) { \
+	.type = IIO_ACCEL, \
+	.modified = 1, \
+	.channel = chan, \
+	.channel2 = IIO_MOD_##axis, \
+	.output = 1, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+}
+
+static const struct iio_chan_spec toshiba_iio_accel_channels[] = {
+	TOSHIBA_IIO_ACCEL_CHANNEL(X, AXIS_X),
+	TOSHIBA_IIO_ACCEL_CHANNEL(Y, AXIS_Y),
+	TOSHIBA_IIO_ACCEL_CHANNEL(Z, AXIS_Z),
+};
+
+static const struct iio_info toshiba_iio_accel_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw = &toshiba_iio_accel_read_raw,
+};
+
 /*
  * Misc device
  */
@@ -2904,6 +2982,11 @@ static int toshiba_acpi_remove(struct acpi_device *acpi_dev)
 
 	remove_toshiba_proc_entries(dev);
 
+	if (dev->accelerometer_supported && dev->indio_dev) {
+		iio_device_unregister(dev->indio_dev);
+		iio_device_free(dev->indio_dev);
+	}
+
 	if (dev->sysfs_created)
 		sysfs_remove_group(&dev->acpi_dev->dev.kobj,
 				   &toshiba_attr_group);
@@ -3051,6 +3134,30 @@ static int toshiba_acpi_add(struct acpi_device *acpi_dev)
 	dev->touchpad_supported = !ret;
 
 	toshiba_accelerometer_available(dev);
+	if (dev->accelerometer_supported) {
+		dev->indio_dev = iio_device_alloc(sizeof(*dev));
+		if (!dev->indio_dev) {
+			pr_err("Unable to allocate iio device\n");
+			goto iio_error;
+		}
+
+		pr_info("Registering Toshiba accelerometer iio device\n");
+
+		dev->indio_dev->info = &toshiba_iio_accel_info;
+		dev->indio_dev->name = "Toshiba accelerometer";
+		dev->indio_dev->dev.parent = &acpi_dev->dev;
+		dev->indio_dev->modes = INDIO_DIRECT_MODE;
+		dev->indio_dev->channels = toshiba_iio_accel_channels;
+		dev->indio_dev->num_channels =
+					ARRAY_SIZE(toshiba_iio_accel_channels);
+
+		ret = iio_device_register(dev->indio_dev);
+		if (ret < 0) {
+			pr_err("Unable to register iio device\n");
+			iio_device_free(dev->indio_dev);
+		}
+	}
+iio_error:
 
 	toshiba_usb_sleep_charge_available(dev);