media: uvcvideo: Implement mask for V4L2_CTRL_TYPE_MENU

Replace the count with a mask field that lets us choose not only the max
value, but also the minimum value and what values are valid in between.
Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/media/usb/uvc/uvc_ctrl.c

@@ -6,6 +6,7 @@
  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
  */
 
+#include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
@@ -525,7 +526,8 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
 		.v4l2_type	= V4L2_CTRL_TYPE_MENU,
 		.data_type	= UVC_CTRL_DATA_TYPE_BITMASK,
 		.menu_info	= exposure_auto_controls,
-		.menu_count	= ARRAY_SIZE(exposure_auto_controls),
+		.menu_mask	= GENMASK(V4L2_EXPOSURE_APERTURE_PRIORITY,
+					  V4L2_EXPOSURE_AUTO),
 		.slave_ids	= { V4L2_CID_EXPOSURE_ABSOLUTE, },
 	},
 	{
@@ -731,7 +733,8 @@ static const struct uvc_control_mapping uvc_ctrl_mappings_uvc11[] = {
 		.v4l2_type	= V4L2_CTRL_TYPE_MENU,
 		.data_type	= UVC_CTRL_DATA_TYPE_ENUM,
 		.menu_info	= power_line_frequency_controls,
-		.menu_count	= ARRAY_SIZE(power_line_frequency_controls) - 1,
+		.menu_mask	= GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_60HZ,
+					  V4L2_CID_POWER_LINE_FREQUENCY_DISABLED),
 	},
 };
 
@@ -745,7 +748,8 @@ static const struct uvc_control_mapping uvc_ctrl_mappings_uvc15[] = {
 		.v4l2_type	= V4L2_CTRL_TYPE_MENU,
 		.data_type	= UVC_CTRL_DATA_TYPE_ENUM,
 		.menu_info	= power_line_frequency_controls,
-		.menu_count	= ARRAY_SIZE(power_line_frequency_controls),
+		.menu_mask	= GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_AUTO,
+					  V4L2_CID_POWER_LINE_FREQUENCY_DISABLED),
 	},
 };
 
@@ -975,7 +979,9 @@ static s32 __uvc_ctrl_get_value(struct uvc_control_mapping *mapping,
 		const struct uvc_menu_info *menu = mapping->menu_info;
 		unsigned int i;
 
-		for (i = 0; i < mapping->menu_count; ++i, ++menu) {
+		for (i = 0; BIT(i) <= mapping->menu_mask; ++i, ++menu) {
+			if (!test_bit(i, &mapping->menu_mask))
+				continue;
 			if (menu->value == value) {
 				value = i;
 				break;
@@ -1228,12 +1234,14 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
 
 	switch (mapping->v4l2_type) {
 	case V4L2_CTRL_TYPE_MENU:
-		v4l2_ctrl->minimum = 0;
-		v4l2_ctrl->maximum = mapping->menu_count - 1;
+		v4l2_ctrl->minimum = ffs(mapping->menu_mask) - 1;
+		v4l2_ctrl->maximum = fls(mapping->menu_mask) - 1;
 		v4l2_ctrl->step = 1;
 
 		menu = mapping->menu_info;
-		for (i = 0; i < mapping->menu_count; ++i, ++menu) {
+		for (i = 0; BIT(i) <= mapping->menu_mask; ++i, ++menu) {
+			if (!test_bit(i, &mapping->menu_mask))
+				continue;
 			if (menu->value == v4l2_ctrl->default_value) {
 				v4l2_ctrl->default_value = i;
 				break;
@@ -1354,7 +1362,7 @@ int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
 		goto done;
 	}
 
-	if (query_menu->index >= mapping->menu_count) {
+	if (!test_bit(query_menu->index, &mapping->menu_mask)) {
 		ret = -EINVAL;
 		goto done;
 	}
@@ -1868,8 +1876,13 @@ int uvc_ctrl_set(struct uvc_fh *handle,
 		break;
 
 	case V4L2_CTRL_TYPE_MENU:
-		if (xctrl->value < 0 || xctrl->value >= mapping->menu_count)
+		if (xctrl->value < (ffs(mapping->menu_mask) - 1) ||
+		    xctrl->value > (fls(mapping->menu_mask) - 1))
 			return -ERANGE;
+
+		if (!test_bit(xctrl->value, &mapping->menu_mask))
+			return -EINVAL;
+
 		value = mapping->menu_info[xctrl->value].value;
 
 		/*
@@ -2306,7 +2319,7 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
 
 	INIT_LIST_HEAD(&map->ev_subs);
 
-	size = sizeof(*mapping->menu_info) * mapping->menu_count;
+	size = sizeof(*mapping->menu_info) * fls(mapping->menu_mask);
 	map->menu_info = kmemdup(mapping->menu_info, size, GFP_KERNEL);
 	if (!map->menu_info)
 		goto err_nomem;

drivers/media/usb/uvc/uvc_driver.c

@@ -7,6 +7,7 @@
  */
 
 #include <linux/atomic.h>
+#include <linux/bits.h>
 #include <linux/gpio/consumer.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
@@ -2371,7 +2372,8 @@ static const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited = {
 	.v4l2_type	= V4L2_CTRL_TYPE_MENU,
 	.data_type	= UVC_CTRL_DATA_TYPE_ENUM,
 	.menu_info	= power_line_frequency_controls_limited,
-	.menu_count	= ARRAY_SIZE(power_line_frequency_controls_limited),
+	.menu_mask	=
+		GENMASK(ARRAY_SIZE(power_line_frequency_controls_limited) - 1, 0),
 };
 
 static const struct uvc_device_info uvc_ctrl_power_line_limited = {

drivers/media/usb/uvc/uvc_v4l2.c

@@ -6,6 +6,7 @@
  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
  */
 
+#include <linux/bits.h>
 #include <linux/compat.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
@@ -80,7 +81,7 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
 			goto free_map;
 		}
 
-		map->menu_count = xmap->menu_count;
+		map->menu_mask = GENMASK(xmap->menu_count - 1, 0);
 		break;
 
 	default:

drivers/media/usb/uvc/uvcvideo.h

@@ -115,7 +115,7 @@ struct uvc_control_mapping {
 	u32 data_type;
 
 	const struct uvc_menu_info *menu_info;
-	u32 menu_count;
+	unsigned long menu_mask;
 
 	u32 master_id;
 	s32 master_manual;