1 /*
2  * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sub license,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the
12  * next paragraph) shall be included in all copies or substantial portions
13  * of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21  * DEALINGS IN THE SOFTWARE.
22  */
23 
24 #include <linux/backlight.h>
25 #include <linux/err.h>
26 #include <linux/module.h>
27 
28 #include <drm/drm_crtc.h>
29 #include <drm/drm_panel.h>
30 #include <drm/drm_print.h>
31 
32 static DEFINE_MUTEX(panel_lock);
33 static LIST_HEAD(panel_list);
34 
35 /**
36  * DOC: drm panel
37  *
38  * The DRM panel helpers allow drivers to register panel objects with a
39  * central registry and provide functions to retrieve those panels in display
40  * drivers.
41  *
42  * For easy integration into drivers using the &drm_bridge infrastructure please
43  * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
44  */
45 
46 /**
47  * drm_panel_init - initialize a panel
48  * @panel: DRM panel
49  * @dev: parent device of the panel
50  * @funcs: panel operations
51  * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
52  *	the panel interface
53  *
54  * Initialize the panel structure for subsequent registration with
55  * drm_panel_add().
56  */
drm_panel_init(struct drm_panel * panel,struct device * dev,const struct drm_panel_funcs * funcs,int connector_type)57 void drm_panel_init(struct drm_panel *panel, struct device *dev,
58 		    const struct drm_panel_funcs *funcs, int connector_type)
59 {
60 	INIT_LIST_HEAD(&panel->list);
61 	panel->dev = dev;
62 	panel->funcs = funcs;
63 	panel->connector_type = connector_type;
64 }
65 EXPORT_SYMBOL(drm_panel_init);
66 
67 /**
68  * drm_panel_add - add a panel to the global registry
69  * @panel: panel to add
70  *
71  * Add a panel to the global registry so that it can be looked up by display
72  * drivers.
73  */
drm_panel_add(struct drm_panel * panel)74 void drm_panel_add(struct drm_panel *panel)
75 {
76 	mutex_lock(&panel_lock);
77 	list_add_tail(&panel->list, &panel_list);
78 	mutex_unlock(&panel_lock);
79 }
80 EXPORT_SYMBOL(drm_panel_add);
81 
82 /**
83  * drm_panel_remove - remove a panel from the global registry
84  * @panel: DRM panel
85  *
86  * Removes a panel from the global registry.
87  */
drm_panel_remove(struct drm_panel * panel)88 void drm_panel_remove(struct drm_panel *panel)
89 {
90 	mutex_lock(&panel_lock);
91 	list_del_init(&panel->list);
92 	mutex_unlock(&panel_lock);
93 }
94 EXPORT_SYMBOL(drm_panel_remove);
95 
96 /**
97  * drm_panel_prepare - power on a panel
98  * @panel: DRM panel
99  *
100  * Calling this function will enable power and deassert any reset signals to
101  * the panel. After this has completed it is possible to communicate with any
102  * integrated circuitry via a command bus.
103  *
104  * Return: 0 on success or a negative error code on failure.
105  */
drm_panel_prepare(struct drm_panel * panel)106 int drm_panel_prepare(struct drm_panel *panel)
107 {
108 	if (!panel)
109 		return -EINVAL;
110 
111 	if (panel->funcs && panel->funcs->prepare)
112 		return panel->funcs->prepare(panel);
113 
114 	return 0;
115 }
116 EXPORT_SYMBOL(drm_panel_prepare);
117 
118 /**
119  * drm_panel_unprepare - power off a panel
120  * @panel: DRM panel
121  *
122  * Calling this function will completely power off a panel (assert the panel's
123  * reset, turn off power supplies, ...). After this function has completed, it
124  * is usually no longer possible to communicate with the panel until another
125  * call to drm_panel_prepare().
126  *
127  * Return: 0 on success or a negative error code on failure.
128  */
drm_panel_unprepare(struct drm_panel * panel)129 int drm_panel_unprepare(struct drm_panel *panel)
130 {
131 	if (!panel)
132 		return -EINVAL;
133 
134 	if (panel->funcs && panel->funcs->unprepare)
135 		return panel->funcs->unprepare(panel);
136 
137 	return 0;
138 }
139 EXPORT_SYMBOL(drm_panel_unprepare);
140 
141 /**
142  * drm_panel_enable - enable a panel
143  * @panel: DRM panel
144  *
145  * Calling this function will cause the panel display drivers to be turned on
146  * and the backlight to be enabled. Content will be visible on screen after
147  * this call completes.
148  *
149  * Return: 0 on success or a negative error code on failure.
150  */
drm_panel_enable(struct drm_panel * panel)151 int drm_panel_enable(struct drm_panel *panel)
152 {
153 	int ret;
154 
155 	if (!panel)
156 		return -EINVAL;
157 
158 	if (panel->funcs && panel->funcs->enable) {
159 		ret = panel->funcs->enable(panel);
160 		if (ret < 0)
161 			return ret;
162 	}
163 
164 	ret = backlight_enable(panel->backlight);
165 	if (ret < 0)
166 		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
167 			     ret);
168 
169 	return 0;
170 }
171 EXPORT_SYMBOL(drm_panel_enable);
172 
173 /**
174  * drm_panel_disable - disable a panel
175  * @panel: DRM panel
176  *
177  * This will typically turn off the panel's backlight or disable the display
178  * drivers. For smart panels it should still be possible to communicate with
179  * the integrated circuitry via any command bus after this call.
180  *
181  * Return: 0 on success or a negative error code on failure.
182  */
drm_panel_disable(struct drm_panel * panel)183 int drm_panel_disable(struct drm_panel *panel)
184 {
185 	int ret;
186 
187 	if (!panel)
188 		return -EINVAL;
189 
190 	ret = backlight_disable(panel->backlight);
191 	if (ret < 0)
192 		DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
193 			     ret);
194 
195 	if (panel->funcs && panel->funcs->disable)
196 		return panel->funcs->disable(panel);
197 
198 	return 0;
199 }
200 EXPORT_SYMBOL(drm_panel_disable);
201 
202 /**
203  * drm_panel_get_modes - probe the available display modes of a panel
204  * @panel: DRM panel
205  * @connector: DRM connector
206  *
207  * The modes probed from the panel are automatically added to the connector
208  * that the panel is attached to.
209  *
210  * Return: The number of modes available from the panel on success or a
211  * negative error code on failure.
212  */
drm_panel_get_modes(struct drm_panel * panel,struct drm_connector * connector)213 int drm_panel_get_modes(struct drm_panel *panel,
214 			struct drm_connector *connector)
215 {
216 	if (!panel)
217 		return -EINVAL;
218 
219 	if (panel->funcs && panel->funcs->get_modes)
220 		return panel->funcs->get_modes(panel, connector);
221 
222 	return -EOPNOTSUPP;
223 }
224 EXPORT_SYMBOL(drm_panel_get_modes);
225 
226 #ifdef CONFIG_OF
227 /**
228  * of_drm_find_panel - look up a panel using a device tree node
229  * @np: device tree node of the panel
230  *
231  * Searches the set of registered panels for one that matches the given device
232  * tree node. If a matching panel is found, return a pointer to it.
233  *
234  * Return: A pointer to the panel registered for the specified device tree
235  * node or an ERR_PTR() if no panel matching the device tree node can be found.
236  *
237  * Possible error codes returned by this function:
238  *
239  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
240  *   should retry later
241  * - ENODEV: the device is not available (status != "okay" or "ok")
242  */
of_drm_find_panel(const struct device_node * np)243 struct drm_panel *of_drm_find_panel(const struct device_node *np)
244 {
245 	struct drm_panel *panel;
246 
247 	if (!of_device_is_available(np))
248 		return ERR_PTR(-ENODEV);
249 
250 	mutex_lock(&panel_lock);
251 
252 	list_for_each_entry(panel, &panel_list, list) {
253 		if (panel->dev->of_node == np) {
254 			mutex_unlock(&panel_lock);
255 			return panel;
256 		}
257 	}
258 
259 	mutex_unlock(&panel_lock);
260 	return ERR_PTR(-EPROBE_DEFER);
261 }
262 EXPORT_SYMBOL(of_drm_find_panel);
263 
264 /**
265  * of_drm_get_panel_orientation - look up the orientation of the panel through
266  * the "rotation" binding from a device tree node
267  * @np: device tree node of the panel
268  * @orientation: orientation enum to be filled in
269  *
270  * Looks up the rotation of a panel in the device tree. The orientation of the
271  * panel is expressed as a property name "rotation" in the device tree. The
272  * rotation in the device tree is counter clockwise.
273  *
274  * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the
275  * rotation property doesn't exist. Return a negative error code on failure.
276  */
of_drm_get_panel_orientation(const struct device_node * np,enum drm_panel_orientation * orientation)277 int of_drm_get_panel_orientation(const struct device_node *np,
278 				 enum drm_panel_orientation *orientation)
279 {
280 	int rotation, ret;
281 
282 	ret = of_property_read_u32(np, "rotation", &rotation);
283 	if (ret == -EINVAL) {
284 		/* Don't return an error if there's no rotation property. */
285 		*orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
286 		return 0;
287 	}
288 
289 	if (ret < 0)
290 		return ret;
291 
292 	if (rotation == 0)
293 		*orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
294 	else if (rotation == 90)
295 		*orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
296 	else if (rotation == 180)
297 		*orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
298 	else if (rotation == 270)
299 		*orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
300 	else
301 		return -EINVAL;
302 
303 	return 0;
304 }
305 EXPORT_SYMBOL(of_drm_get_panel_orientation);
306 #endif
307 
308 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
309 /**
310  * drm_panel_of_backlight - use backlight device node for backlight
311  * @panel: DRM panel
312  *
313  * Use this function to enable backlight handling if your panel
314  * uses device tree and has a backlight phandle.
315  *
316  * When the panel is enabled backlight will be enabled after a
317  * successful call to &drm_panel_funcs.enable()
318  *
319  * When the panel is disabled backlight will be disabled before the
320  * call to &drm_panel_funcs.disable().
321  *
322  * A typical implementation for a panel driver supporting device tree
323  * will call this function at probe time. Backlight will then be handled
324  * transparently without requiring any intervention from the driver.
325  * drm_panel_of_backlight() must be called after the call to drm_panel_init().
326  *
327  * Return: 0 on success or a negative error code on failure.
328  */
drm_panel_of_backlight(struct drm_panel * panel)329 int drm_panel_of_backlight(struct drm_panel *panel)
330 {
331 	struct backlight_device *backlight;
332 
333 	if (!panel || !panel->dev)
334 		return -EINVAL;
335 
336 	backlight = devm_of_find_backlight(panel->dev);
337 
338 	if (IS_ERR(backlight))
339 		return PTR_ERR(backlight);
340 
341 	panel->backlight = backlight;
342 	return 0;
343 }
344 EXPORT_SYMBOL(drm_panel_of_backlight);
345 #endif
346 
347 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
348 MODULE_DESCRIPTION("DRM panel infrastructure");
349 MODULE_LICENSE("GPL and additional rights");
350