drm/sun4i: tcon: fix check of tcon->panel null pointer
[sfrench/cifs-2.6.git] / drivers / gpu / drm / sun4i / sun4i_lvds.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2017 Free Electrons
4  * Maxime Ripard <maxime.ripard@free-electrons.com>
5  */
6
7 #include <linux/clk.h>
8
9 #include <drm/drmP.h>
10 #include <drm/drm_atomic_helper.h>
11 #include <drm/drm_crtc_helper.h>
12 #include <drm/drm_of.h>
13 #include <drm/drm_panel.h>
14
15 #include "sun4i_crtc.h"
16 #include "sun4i_tcon.h"
17 #include "sun4i_lvds.h"
18
19 struct sun4i_lvds {
20         struct drm_connector    connector;
21         struct drm_encoder      encoder;
22
23         struct sun4i_tcon       *tcon;
24 };
25
26 static inline struct sun4i_lvds *
27 drm_connector_to_sun4i_lvds(struct drm_connector *connector)
28 {
29         return container_of(connector, struct sun4i_lvds,
30                             connector);
31 }
32
33 static inline struct sun4i_lvds *
34 drm_encoder_to_sun4i_lvds(struct drm_encoder *encoder)
35 {
36         return container_of(encoder, struct sun4i_lvds,
37                             encoder);
38 }
39
40 static int sun4i_lvds_get_modes(struct drm_connector *connector)
41 {
42         struct sun4i_lvds *lvds =
43                 drm_connector_to_sun4i_lvds(connector);
44         struct sun4i_tcon *tcon = lvds->tcon;
45
46         return drm_panel_get_modes(tcon->panel);
47 }
48
49 static struct drm_connector_helper_funcs sun4i_lvds_con_helper_funcs = {
50         .get_modes      = sun4i_lvds_get_modes,
51 };
52
53 static void
54 sun4i_lvds_connector_destroy(struct drm_connector *connector)
55 {
56         struct sun4i_lvds *lvds = drm_connector_to_sun4i_lvds(connector);
57         struct sun4i_tcon *tcon = lvds->tcon;
58
59         drm_panel_detach(tcon->panel);
60         drm_connector_cleanup(connector);
61 }
62
63 static const struct drm_connector_funcs sun4i_lvds_con_funcs = {
64         .fill_modes             = drm_helper_probe_single_connector_modes,
65         .destroy                = sun4i_lvds_connector_destroy,
66         .reset                  = drm_atomic_helper_connector_reset,
67         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
68         .atomic_destroy_state   = drm_atomic_helper_connector_destroy_state,
69 };
70
71 static void sun4i_lvds_encoder_enable(struct drm_encoder *encoder)
72 {
73         struct sun4i_lvds *lvds = drm_encoder_to_sun4i_lvds(encoder);
74         struct sun4i_tcon *tcon = lvds->tcon;
75
76         DRM_DEBUG_DRIVER("Enabling LVDS output\n");
77
78         if (tcon->panel) {
79                 drm_panel_prepare(tcon->panel);
80                 drm_panel_enable(tcon->panel);
81         }
82 }
83
84 static void sun4i_lvds_encoder_disable(struct drm_encoder *encoder)
85 {
86         struct sun4i_lvds *lvds = drm_encoder_to_sun4i_lvds(encoder);
87         struct sun4i_tcon *tcon = lvds->tcon;
88
89         DRM_DEBUG_DRIVER("Disabling LVDS output\n");
90
91         if (tcon->panel) {
92                 drm_panel_disable(tcon->panel);
93                 drm_panel_unprepare(tcon->panel);
94         }
95 }
96
97 static const struct drm_encoder_helper_funcs sun4i_lvds_enc_helper_funcs = {
98         .disable        = sun4i_lvds_encoder_disable,
99         .enable         = sun4i_lvds_encoder_enable,
100 };
101
102 static const struct drm_encoder_funcs sun4i_lvds_enc_funcs = {
103         .destroy        = drm_encoder_cleanup,
104 };
105
106 int sun4i_lvds_init(struct drm_device *drm, struct sun4i_tcon *tcon)
107 {
108         struct drm_encoder *encoder;
109         struct drm_bridge *bridge;
110         struct sun4i_lvds *lvds;
111         int ret;
112
113         lvds = devm_kzalloc(drm->dev, sizeof(*lvds), GFP_KERNEL);
114         if (!lvds)
115                 return -ENOMEM;
116         lvds->tcon = tcon;
117         encoder = &lvds->encoder;
118
119         ret = drm_of_find_panel_or_bridge(tcon->dev->of_node, 1, 0,
120                                           &tcon->panel, &bridge);
121         if (ret) {
122                 dev_info(drm->dev, "No panel or bridge found... LVDS output disabled\n");
123                 return 0;
124         }
125
126         drm_encoder_helper_add(&lvds->encoder,
127                                &sun4i_lvds_enc_helper_funcs);
128         ret = drm_encoder_init(drm,
129                                &lvds->encoder,
130                                &sun4i_lvds_enc_funcs,
131                                DRM_MODE_ENCODER_LVDS,
132                                NULL);
133         if (ret) {
134                 dev_err(drm->dev, "Couldn't initialise the lvds encoder\n");
135                 goto err_out;
136         }
137
138         /* The LVDS encoder can only work with the TCON channel 0 */
139         lvds->encoder.possible_crtcs = drm_crtc_mask(&tcon->crtc->crtc);
140
141         if (tcon->panel) {
142                 drm_connector_helper_add(&lvds->connector,
143                                          &sun4i_lvds_con_helper_funcs);
144                 ret = drm_connector_init(drm, &lvds->connector,
145                                          &sun4i_lvds_con_funcs,
146                                          DRM_MODE_CONNECTOR_LVDS);
147                 if (ret) {
148                         dev_err(drm->dev, "Couldn't initialise the lvds connector\n");
149                         goto err_cleanup_connector;
150                 }
151
152                 drm_connector_attach_encoder(&lvds->connector,
153                                                   &lvds->encoder);
154
155                 ret = drm_panel_attach(tcon->panel, &lvds->connector);
156                 if (ret) {
157                         dev_err(drm->dev, "Couldn't attach our panel\n");
158                         goto err_cleanup_connector;
159                 }
160         }
161
162         if (bridge) {
163                 ret = drm_bridge_attach(encoder, bridge, NULL);
164                 if (ret) {
165                         dev_err(drm->dev, "Couldn't attach our bridge\n");
166                         goto err_cleanup_connector;
167                 }
168         }
169
170         return 0;
171
172 err_cleanup_connector:
173         drm_encoder_cleanup(&lvds->encoder);
174 err_out:
175         return ret;
176 }
177 EXPORT_SYMBOL(sun4i_lvds_init);