1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2019 Renesas Electronics Corporation
4  * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
5  */
6 
7 #include <linux/gpio/consumer.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/of_device.h>
11 #include <linux/of_graph.h>
12 #include <linux/platform_device.h>
13 #include <linux/regulator/consumer.h>
14 
15 #include <drm/drm_atomic_helper.h>
16 #include <drm/drm_bridge.h>
17 #include <drm/drm_of.h>
18 #include <drm/drm_panel.h>
19 
20 struct lvds_codec {
21 	struct device *dev;
22 	struct drm_bridge bridge;
23 	struct drm_bridge *panel_bridge;
24 	struct drm_bridge_timings timings;
25 	struct regulator *vcc;
26 	struct gpio_desc *powerdown_gpio;
27 	u32 connector_type;
28 	unsigned int bus_format;
29 };
30 
31 static inline struct lvds_codec *to_lvds_codec(struct drm_bridge *bridge)
32 {
33 	return container_of(bridge, struct lvds_codec, bridge);
34 }
35 
36 static int lvds_codec_attach(struct drm_bridge *bridge,
37 			     enum drm_bridge_attach_flags flags)
38 {
39 	struct lvds_codec *lvds_codec = to_lvds_codec(bridge);
40 
41 	return drm_bridge_attach(bridge->encoder, lvds_codec->panel_bridge,
42 				 bridge, flags);
43 }
44 
45 static void lvds_codec_enable(struct drm_bridge *bridge)
46 {
47 	struct lvds_codec *lvds_codec = to_lvds_codec(bridge);
48 	int ret;
49 
50 	ret = regulator_enable(lvds_codec->vcc);
51 	if (ret) {
52 		dev_err(lvds_codec->dev,
53 			"Failed to enable regulator \"vcc\": %d\n", ret);
54 		return;
55 	}
56 
57 	if (lvds_codec->powerdown_gpio)
58 		gpiod_set_value_cansleep(lvds_codec->powerdown_gpio, 0);
59 }
60 
61 static void lvds_codec_disable(struct drm_bridge *bridge)
62 {
63 	struct lvds_codec *lvds_codec = to_lvds_codec(bridge);
64 	int ret;
65 
66 	if (lvds_codec->powerdown_gpio)
67 		gpiod_set_value_cansleep(lvds_codec->powerdown_gpio, 1);
68 
69 	ret = regulator_disable(lvds_codec->vcc);
70 	if (ret)
71 		dev_err(lvds_codec->dev,
72 			"Failed to disable regulator \"vcc\": %d\n", ret);
73 }
74 
75 static const struct drm_bridge_funcs funcs = {
76 	.attach = lvds_codec_attach,
77 	.enable = lvds_codec_enable,
78 	.disable = lvds_codec_disable,
79 };
80 
81 #define MAX_INPUT_SEL_FORMATS 1
82 static u32 *
83 lvds_codec_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
84 				     struct drm_bridge_state *bridge_state,
85 				     struct drm_crtc_state *crtc_state,
86 				     struct drm_connector_state *conn_state,
87 				     u32 output_fmt,
88 				     unsigned int *num_input_fmts)
89 {
90 	struct lvds_codec *lvds_codec = to_lvds_codec(bridge);
91 	u32 *input_fmts;
92 
93 	*num_input_fmts = 0;
94 
95 	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
96 			     GFP_KERNEL);
97 	if (!input_fmts)
98 		return NULL;
99 
100 	input_fmts[0] = lvds_codec->bus_format;
101 	*num_input_fmts = MAX_INPUT_SEL_FORMATS;
102 
103 	return input_fmts;
104 }
105 
106 static const struct drm_bridge_funcs funcs_decoder = {
107 	.attach = lvds_codec_attach,
108 	.enable = lvds_codec_enable,
109 	.disable = lvds_codec_disable,
110 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
111 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
112 	.atomic_reset = drm_atomic_helper_bridge_reset,
113 	.atomic_get_input_bus_fmts = lvds_codec_atomic_get_input_bus_fmts,
114 };
115 
116 static int lvds_codec_probe(struct platform_device *pdev)
117 {
118 	struct device *dev = &pdev->dev;
119 	struct device_node *panel_node;
120 	struct device_node *bus_node;
121 	struct drm_panel *panel;
122 	struct lvds_codec *lvds_codec;
123 	u32 val;
124 	int ret;
125 
126 	lvds_codec = devm_kzalloc(dev, sizeof(*lvds_codec), GFP_KERNEL);
127 	if (!lvds_codec)
128 		return -ENOMEM;
129 
130 	lvds_codec->dev = &pdev->dev;
131 	lvds_codec->connector_type = (uintptr_t)of_device_get_match_data(dev);
132 
133 	lvds_codec->vcc = devm_regulator_get(lvds_codec->dev, "power");
134 	if (IS_ERR(lvds_codec->vcc))
135 		return dev_err_probe(dev, PTR_ERR(lvds_codec->vcc),
136 				     "Unable to get \"vcc\" supply\n");
137 
138 	lvds_codec->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
139 							     GPIOD_OUT_HIGH);
140 	if (IS_ERR(lvds_codec->powerdown_gpio))
141 		return dev_err_probe(dev, PTR_ERR(lvds_codec->powerdown_gpio),
142 				     "powerdown GPIO failure\n");
143 
144 	/* Locate the panel DT node. */
145 	panel_node = of_graph_get_remote_node(dev->of_node, 1, 0);
146 	if (!panel_node) {
147 		dev_dbg(dev, "panel DT node not found\n");
148 		return -ENXIO;
149 	}
150 
151 	panel = of_drm_find_panel(panel_node);
152 	of_node_put(panel_node);
153 	if (IS_ERR(panel)) {
154 		dev_dbg(dev, "panel not found, deferring probe\n");
155 		return PTR_ERR(panel);
156 	}
157 
158 	lvds_codec->panel_bridge =
159 		devm_drm_panel_bridge_add_typed(dev, panel,
160 						lvds_codec->connector_type);
161 	if (IS_ERR(lvds_codec->panel_bridge))
162 		return PTR_ERR(lvds_codec->panel_bridge);
163 
164 	lvds_codec->bridge.funcs = &funcs;
165 
166 	/*
167 	 * Decoder input LVDS format is a property of the decoder chip or even
168 	 * its strapping. Handle data-mapping the same way lvds-panel does. In
169 	 * case data-mapping is not present, do nothing, since there are still
170 	 * legacy bindings which do not specify this property.
171 	 */
172 	if (lvds_codec->connector_type != DRM_MODE_CONNECTOR_LVDS) {
173 		bus_node = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
174 		if (!bus_node) {
175 			dev_dbg(dev, "bus DT node not found\n");
176 			return -ENXIO;
177 		}
178 
179 		ret = drm_of_lvds_get_data_mapping(bus_node);
180 		of_node_put(bus_node);
181 		if (ret == -ENODEV) {
182 			dev_warn(dev, "missing 'data-mapping' DT property\n");
183 		} else if (ret) {
184 			dev_err(dev, "invalid 'data-mapping' DT property\n");
185 			return ret;
186 		} else {
187 			lvds_codec->bus_format = ret;
188 			lvds_codec->bridge.funcs = &funcs_decoder;
189 		}
190 	}
191 
192 	/*
193 	 * Encoder might sample data on different clock edge than the display,
194 	 * for example OnSemi FIN3385 has a dedicated strapping pin to select
195 	 * the sampling edge.
196 	 */
197 	if (lvds_codec->connector_type == DRM_MODE_CONNECTOR_LVDS &&
198 	    !of_property_read_u32(dev->of_node, "pclk-sample", &val)) {
199 		lvds_codec->timings.input_bus_flags = val ?
200 			DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE :
201 			DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE;
202 	}
203 
204 	/*
205 	 * The panel_bridge bridge is attached to the panel's of_node,
206 	 * but we need a bridge attached to our of_node for our user
207 	 * to look up.
208 	 */
209 	lvds_codec->bridge.of_node = dev->of_node;
210 	lvds_codec->bridge.timings = &lvds_codec->timings;
211 	drm_bridge_add(&lvds_codec->bridge);
212 
213 	platform_set_drvdata(pdev, lvds_codec);
214 
215 	return 0;
216 }
217 
218 static int lvds_codec_remove(struct platform_device *pdev)
219 {
220 	struct lvds_codec *lvds_codec = platform_get_drvdata(pdev);
221 
222 	drm_bridge_remove(&lvds_codec->bridge);
223 
224 	return 0;
225 }
226 
227 static const struct of_device_id lvds_codec_match[] = {
228 	{
229 		.compatible = "lvds-decoder",
230 		.data = (void *)DRM_MODE_CONNECTOR_DPI,
231 	},
232 	{
233 		.compatible = "lvds-encoder",
234 		.data = (void *)DRM_MODE_CONNECTOR_LVDS,
235 	},
236 	{
237 		.compatible = "thine,thc63lvdm83d",
238 		.data = (void *)DRM_MODE_CONNECTOR_LVDS,
239 	},
240 	{},
241 };
242 MODULE_DEVICE_TABLE(of, lvds_codec_match);
243 
244 static struct platform_driver lvds_codec_driver = {
245 	.probe	= lvds_codec_probe,
246 	.remove	= lvds_codec_remove,
247 	.driver		= {
248 		.name		= "lvds-codec",
249 		.of_match_table	= lvds_codec_match,
250 	},
251 };
252 module_platform_driver(lvds_codec_driver);
253 
254 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
255 MODULE_DESCRIPTION("LVDS encoders and decoders");
256 MODULE_LICENSE("GPL");
257