1/*	$NetBSD: drm_panel.c,v 1.5 2021/12/18 23:44:57 riastradh Exp $	*/
2
3/*
4 * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sub license,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the
14 * next paragraph) shall be included in all copies or substantial portions
15 * of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23 * DEALINGS IN THE SOFTWARE.
24 */
25
26#include <sys/cdefs.h>
27__KERNEL_RCSID(0, "$NetBSD: drm_panel.c,v 1.5 2021/12/18 23:44:57 riastradh Exp $");
28
29#include <linux/backlight.h>
30#include <linux/err.h>
31#include <linux/module.h>
32
33#include <drm/drm_crtc.h>
34#include <drm/drm_panel.h>
35#include <drm/drm_print.h>
36
37#ifdef __NetBSD__
38static struct mutex panel_lock;
39static struct list_head panel_list = LIST_HEAD_INIT(panel_list);
40#else
41static DEFINE_MUTEX(panel_lock);
42static LIST_HEAD(panel_list);
43#endif
44
45#ifdef __NetBSD__
46void drm_panel_init_lock(void)
47{
48	linux_mutex_init(&panel_lock);
49}
50void drm_panel_fini_lock(void)
51{
52	linux_mutex_destroy(&panel_lock);
53}
54#endif
55
56/**
57 * DOC: drm panel
58 *
59 * The DRM panel helpers allow drivers to register panel objects with a
60 * central registry and provide functions to retrieve those panels in display
61 * drivers.
62 *
63 * For easy integration into drivers using the &drm_bridge infrastructure please
64 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
65 */
66
67/**
68 * drm_panel_init - initialize a panel
69 * @panel: DRM panel
70 * @dev: parent device of the panel
71 * @funcs: panel operations
72 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
73 *	the panel interface
74 *
75 * Initialize the panel structure for subsequent registration with
76 * drm_panel_add().
77 */
78void drm_panel_init(struct drm_panel *panel, struct device *dev,
79		    const struct drm_panel_funcs *funcs, int connector_type)
80{
81	INIT_LIST_HEAD(&panel->list);
82	panel->dev = dev;
83	panel->funcs = funcs;
84	panel->connector_type = connector_type;
85}
86EXPORT_SYMBOL(drm_panel_init);
87
88/**
89 * drm_panel_add - add a panel to the global registry
90 * @panel: panel to add
91 *
92 * Add a panel to the global registry so that it can be looked up by display
93 * drivers.
94 *
95 * Return: 0 on success or a negative error code on failure.
96 */
97int drm_panel_add(struct drm_panel *panel)
98{
99	mutex_lock(&panel_lock);
100	list_add_tail(&panel->list, &panel_list);
101	mutex_unlock(&panel_lock);
102
103	return 0;
104}
105EXPORT_SYMBOL(drm_panel_add);
106
107/**
108 * drm_panel_remove - remove a panel from the global registry
109 * @panel: DRM panel
110 *
111 * Removes a panel from the global registry.
112 */
113void drm_panel_remove(struct drm_panel *panel)
114{
115	mutex_lock(&panel_lock);
116	list_del_init(&panel->list);
117	mutex_unlock(&panel_lock);
118}
119EXPORT_SYMBOL(drm_panel_remove);
120
121/**
122 * drm_panel_attach - attach a panel to a connector
123 * @panel: DRM panel
124 * @connector: DRM connector
125 *
126 * After obtaining a pointer to a DRM panel a display driver calls this
127 * function to attach a panel to a connector.
128 *
129 * An error is returned if the panel is already attached to another connector.
130 *
131 * When unloading, the driver should detach from the panel by calling
132 * drm_panel_detach().
133 *
134 * Return: 0 on success or a negative error code on failure.
135 */
136int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
137{
138	return 0;
139}
140EXPORT_SYMBOL(drm_panel_attach);
141
142/**
143 * drm_panel_detach - detach a panel from a connector
144 * @panel: DRM panel
145 *
146 * Detaches a panel from the connector it is attached to. If a panel is not
147 * attached to any connector this is effectively a no-op.
148 *
149 * This function should not be called by the panel device itself. It
150 * is only for the drm device that called drm_panel_attach().
151 */
152void drm_panel_detach(struct drm_panel *panel)
153{
154}
155EXPORT_SYMBOL(drm_panel_detach);
156
157/**
158 * drm_panel_prepare - power on a panel
159 * @panel: DRM panel
160 *
161 * Calling this function will enable power and deassert any reset signals to
162 * the panel. After this has completed it is possible to communicate with any
163 * integrated circuitry via a command bus.
164 *
165 * Return: 0 on success or a negative error code on failure.
166 */
167int drm_panel_prepare(struct drm_panel *panel)
168{
169	if (!panel)
170		return -EINVAL;
171
172	if (panel->funcs && panel->funcs->prepare)
173		return panel->funcs->prepare(panel);
174
175	return 0;
176}
177EXPORT_SYMBOL(drm_panel_prepare);
178
179/**
180 * drm_panel_unprepare - power off a panel
181 * @panel: DRM panel
182 *
183 * Calling this function will completely power off a panel (assert the panel's
184 * reset, turn off power supplies, ...). After this function has completed, it
185 * is usually no longer possible to communicate with the panel until another
186 * call to drm_panel_prepare().
187 *
188 * Return: 0 on success or a negative error code on failure.
189 */
190int drm_panel_unprepare(struct drm_panel *panel)
191{
192	if (!panel)
193		return -EINVAL;
194
195	if (panel->funcs && panel->funcs->unprepare)
196		return panel->funcs->unprepare(panel);
197
198	return 0;
199}
200EXPORT_SYMBOL(drm_panel_unprepare);
201
202/**
203 * drm_panel_enable - enable a panel
204 * @panel: DRM panel
205 *
206 * Calling this function will cause the panel display drivers to be turned on
207 * and the backlight to be enabled. Content will be visible on screen after
208 * this call completes.
209 *
210 * Return: 0 on success or a negative error code on failure.
211 */
212int drm_panel_enable(struct drm_panel *panel)
213{
214	int ret;
215
216	if (!panel)
217		return -EINVAL;
218
219	if (panel->funcs && panel->funcs->enable) {
220		ret = panel->funcs->enable(panel);
221		if (ret < 0)
222			return ret;
223	}
224
225	ret = backlight_enable(panel->backlight);
226	if (ret < 0)
227		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
228			     ret);
229
230	return 0;
231}
232EXPORT_SYMBOL(drm_panel_enable);
233
234/**
235 * drm_panel_disable - disable a panel
236 * @panel: DRM panel
237 *
238 * This will typically turn off the panel's backlight or disable the display
239 * drivers. For smart panels it should still be possible to communicate with
240 * the integrated circuitry via any command bus after this call.
241 *
242 * Return: 0 on success or a negative error code on failure.
243 */
244int drm_panel_disable(struct drm_panel *panel)
245{
246	int ret;
247
248	if (!panel)
249		return -EINVAL;
250
251	ret = backlight_disable(panel->backlight);
252	if (ret < 0)
253		DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
254			     ret);
255
256	if (panel->funcs && panel->funcs->disable)
257		return panel->funcs->disable(panel);
258
259	return 0;
260}
261EXPORT_SYMBOL(drm_panel_disable);
262
263/**
264 * drm_panel_get_modes - probe the available display modes of a panel
265 * @panel: DRM panel
266 * @connector: DRM connector
267 *
268 * The modes probed from the panel are automatically added to the connector
269 * that the panel is attached to.
270 *
271 * Return: The number of modes available from the panel on success or a
272 * negative error code on failure.
273 */
274int drm_panel_get_modes(struct drm_panel *panel,
275			struct drm_connector *connector)
276{
277	if (!panel)
278		return -EINVAL;
279
280	if (panel->funcs && panel->funcs->get_modes)
281		return panel->funcs->get_modes(panel, connector);
282
283	return -EOPNOTSUPP;
284}
285EXPORT_SYMBOL(drm_panel_get_modes);
286
287#ifdef CONFIG_OF
288/**
289 * of_drm_find_panel - look up a panel using a device tree node
290 * @np: device tree node of the panel
291 *
292 * Searches the set of registered panels for one that matches the given device
293 * tree node. If a matching panel is found, return a pointer to it.
294 *
295 * Return: A pointer to the panel registered for the specified device tree
296 * node or an ERR_PTR() if no panel matching the device tree node can be found.
297 *
298 * Possible error codes returned by this function:
299 *
300 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
301 *   should retry later
302 * - ENODEV: the device is not available (status != "okay" or "ok")
303 */
304struct drm_panel *of_drm_find_panel(const struct device_node *np)
305{
306	struct drm_panel *panel;
307
308	if (!of_device_is_available(np))
309		return ERR_PTR(-ENODEV);
310
311	mutex_lock(&panel_lock);
312
313	list_for_each_entry(panel, &panel_list, list) {
314		if (panel->dev->of_node == np) {
315			mutex_unlock(&panel_lock);
316			return panel;
317		}
318	}
319
320	mutex_unlock(&panel_lock);
321	return ERR_PTR(-EPROBE_DEFER);
322}
323EXPORT_SYMBOL(of_drm_find_panel);
324#endif
325
326#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
327/**
328 * drm_panel_of_backlight - use backlight device node for backlight
329 * @panel: DRM panel
330 *
331 * Use this function to enable backlight handling if your panel
332 * uses device tree and has a backlight phandle.
333 *
334 * When the panel is enabled backlight will be enabled after a
335 * successful call to &drm_panel_funcs.enable()
336 *
337 * When the panel is disabled backlight will be disabled before the
338 * call to &drm_panel_funcs.disable().
339 *
340 * A typical implementation for a panel driver supporting device tree
341 * will call this function at probe time. Backlight will then be handled
342 * transparently without requiring any intervention from the driver.
343 * drm_panel_of_backlight() must be called after the call to drm_panel_init().
344 *
345 * Return: 0 on success or a negative error code on failure.
346 */
347int drm_panel_of_backlight(struct drm_panel *panel)
348{
349	struct backlight_device *backlight;
350
351	if (!panel || !panel->dev)
352		return -EINVAL;
353
354	backlight = devm_of_find_backlight(panel->dev);
355
356	if (IS_ERR(backlight))
357		return PTR_ERR(backlight);
358
359	panel->backlight = backlight;
360	return 0;
361}
362EXPORT_SYMBOL(drm_panel_of_backlight);
363#endif
364
365MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
366MODULE_DESCRIPTION("DRM panel infrastructure");
367MODULE_LICENSE("GPL and additional rights");
368