input: Implemented touchpanel uclass for touchpanel devices

Touchapnel devices are useful in u-boot for implementation of boot
menu user interfaces on tablets and other touch based devices.

This uclass implements start, stop and get_touches interface methods.

Signed-off-by: Ondrej Jirman <megous@megous.com>

drivers/input/Kconfig

@@ -100,3 +100,12 @@ config TWL4030_INPUT
 	bool "Enable TWL4030 Input controller"
 	help
 	  Enable TWL4030 Input controller
+
+config DM_TOUCHPANEL
+	bool "Enable driver model for touchpanel support"
+	depends on DM
+	help
+	  This adds a uclass for touchpanel input and implements support
+	  using driver model. The API is implemented by touchpanel.h and
+	  includes methods to start/stop the device and check for available
+	  input.

drivers/input/Makefile

@@ -14,4 +14,6 @@ obj-$(CONFIG_APPLE_SPI_KEYB) += apple_spi_kbd.o
 obj-$(CONFIG_I8042_KEYB) += i8042.o
 obj-$(CONFIG_TEGRA_KEYBOARD) += input.o tegra-kbc.o
 obj-$(CONFIG_TWL4030_INPUT) += twl4030.o
+obj-$(CONFIG_DM_TOUCHPANEL) += touchpanel-uclass.o
+
 endif

drivers/input/touchpanel-uclass.c

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2018 Ondrej Jirman <megous@megous.com>
+ */
+
+#include <errno.h>
+#include <dm.h>
+#include <dm/uclass-internal.h>
+#include <touchpanel.h>
+
+int touchpanel_start(struct udevice *dev)
+{
+	const struct touchpanel_ops *ops = touchpanel_get_ops(dev);
+
+	if (!ops || !ops->start)
+		return -ENOSYS;
+
+	return ops->start(dev);
+}
+
+int touchpanel_stop(struct udevice *dev)
+{
+	const struct touchpanel_ops *ops = touchpanel_get_ops(dev);
+
+	if (!ops || !ops->stop)
+		return -ENOSYS;
+
+	return ops->stop(dev);
+}
+
+int touchpanel_get_touches(struct udevice *dev,
+			   struct touchpanel_touch* touches, int max_touches)
+{
+	const struct touchpanel_ops *ops = touchpanel_get_ops(dev);
+
+	if (!ops || !ops->get_touches)
+		return -ENOSYS;
+
+	return ops->get_touches(dev, touches, max_touches);
+}
+
+static int touchpanel_pre_probe(struct udevice *dev)
+{
+	struct touchpanel_priv *uc_priv;
+
+	uc_priv = dev_get_uclass_priv(dev);
+	if (!uc_priv)
+		return -ENXIO;
+
+	uc_priv->size_x = dev_read_u32_default(dev, "touchscreen-size-x",
+						-ENODATA);
+	uc_priv->size_y = dev_read_u32_default(dev, "touchscreen-size-y",
+						-ENODATA);
+
+	if (uc_priv->size_x == -ENODATA || uc_priv->size_y == -ENODATA)
+		uc_priv->size_x = uc_priv->size_y = -ENODATA;
+
+	return 0;
+}
+
+UCLASS_DRIVER(touchpanel) = {
+	.id		= UCLASS_TOUCHPANEL,
+	.name		= "touchpanel",
+	.pre_probe	= touchpanel_pre_probe,
+	.per_device_auto = sizeof(struct touchpanel_priv),
+};

include/dm/uclass-id.h

@@ -142,6 +142,7 @@ enum uclass_id {
 	UCLASS_TEE,		/* Trusted Execution Environment device */
 	UCLASS_THERMAL,		/* Thermal sensor */
 	UCLASS_TIMER,		/* Timer device */
+	UCLASS_TOUCHPANEL,	/* Touch panel driver */
 	UCLASS_TPM,		/* Trusted Platform Module TIS interface */
 	UCLASS_UFS,		/* Universal Flash Storage */
 	UCLASS_USB,		/* USB bus */

include/touchpanel.h

@@ -0,0 +1,61 @@
+#ifndef __TOUCHPANEL_H
+#define __TOUCHPANEL_H
+
+/**
+ * struct touchpanel_priv - information about a touchpanel, for the uclass
+ *
+ * @sdev:	stdio device
+ */
+struct touchpanel_priv {
+	int size_x;
+	int size_y;
+};
+
+struct touchpanel_touch {
+	int id;
+	int x;
+	int y;
+};
+
+/**
+ * struct touchpanel_ops - touchpanel device operations
+ */
+struct touchpanel_ops {
+	/**
+	 * start() - enable the touchpanel to be ready for use
+	 *
+	 * @dev:	Device to enable
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*start)(struct udevice *dev);
+
+	/**
+	 * stop() - disable the touchpanel when no-longer needed
+	 *
+	 * @dev:	Device to disable
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*stop)(struct udevice *dev);
+
+	/**
+	 * get_touches() - get list of active touches
+	 *
+	 * @dev:	Device to read from
+	 * @touches:	Array where to store touches. If NULL, the driver will
+	 *              only return number of touches available.
+	 * @max_touches:	Size of an touches array
+	 * @return -EAGAIN if no touch is available, otherwise number of touches
+	 * available.
+	 */
+	int (*get_touches)(struct udevice *dev,
+			   struct touchpanel_touch* touches, int max_touches);
+};
+
+#define touchpanel_get_ops(dev)	((struct touchpanel_ops *)(dev)->driver->ops)
+
+int touchpanel_start(struct udevice *dev);
+int touchpanel_stop(struct udevice *dev);
+int touchpanel_get_touches(struct udevice *dev,
+			   struct touchpanel_touch* touches, int max_touches);
+
+#endif /* __TOUCHPANEL_H */