1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * THC63LVD1024 LVDS to parallel data DRM bridge driver.
4  *
5  * Copyright (C) 2018 Jacopo Mondi <jacopo+renesas@jmondi.org>
6  */
7 
8 #include <linux/gpio/consumer.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/of_graph.h>
12 #include <linux/platform_device.h>
13 #include <linux/regulator/consumer.h>
14 #include <linux/slab.h>
15 
16 #include <drm/drm_bridge.h>
17 #include <drm/drm_panel.h>
18 
19 enum thc63_ports {
20 	THC63_LVDS_IN0,
21 	THC63_LVDS_IN1,
22 	THC63_RGB_OUT0,
23 	THC63_RGB_OUT1,
24 };
25 
26 struct thc63_dev {
27 	struct device *dev;
28 
29 	struct regulator *vcc;
30 
31 	struct gpio_desc *pdwn;
32 	struct gpio_desc *oe;
33 
34 	struct drm_bridge bridge;
35 	struct drm_bridge *next;
36 
37 	struct drm_bridge_timings timings;
38 };
39 
40 static inline struct thc63_dev *to_thc63(struct drm_bridge *bridge)
41 {
42 	return container_of(bridge, struct thc63_dev, bridge);
43 }
44 
45 static int thc63_attach(struct drm_bridge *bridge)
46 {
47 	struct thc63_dev *thc63 = to_thc63(bridge);
48 
49 	return drm_bridge_attach(bridge->encoder, thc63->next, bridge);
50 }
51 
52 static enum drm_mode_status thc63_mode_valid(struct drm_bridge *bridge,
53 					const struct drm_display_mode *mode)
54 {
55 	struct thc63_dev *thc63 = to_thc63(bridge);
56 	unsigned int min_freq;
57 	unsigned int max_freq;
58 
59 	/*
60 	 * The THC63LVD1024 pixel rate range is 8 to 135 MHz in all modes but
61 	 * dual-in, single-out where it is 40 to 150 MHz. As dual-in, dual-out
62 	 * isn't supported by the driver yet, simply derive the limits from the
63 	 * input mode.
64 	 */
65 	if (thc63->timings.dual_link) {
66 		min_freq = 40000;
67 		max_freq = 150000;
68 	} else {
69 		min_freq = 8000;
70 		max_freq = 135000;
71 	}
72 
73 	if (mode->clock < min_freq)
74 		return MODE_CLOCK_LOW;
75 
76 	if (mode->clock > max_freq)
77 		return MODE_CLOCK_HIGH;
78 
79 	return MODE_OK;
80 }
81 
82 static void thc63_enable(struct drm_bridge *bridge)
83 {
84 	struct thc63_dev *thc63 = to_thc63(bridge);
85 	int ret;
86 
87 	ret = regulator_enable(thc63->vcc);
88 	if (ret) {
89 		dev_err(thc63->dev,
90 			"Failed to enable regulator \"vcc\": %d\n", ret);
91 		return;
92 	}
93 
94 	gpiod_set_value(thc63->pdwn, 0);
95 	gpiod_set_value(thc63->oe, 1);
96 }
97 
98 static void thc63_disable(struct drm_bridge *bridge)
99 {
100 	struct thc63_dev *thc63 = to_thc63(bridge);
101 	int ret;
102 
103 	gpiod_set_value(thc63->oe, 0);
104 	gpiod_set_value(thc63->pdwn, 1);
105 
106 	ret = regulator_disable(thc63->vcc);
107 	if (ret)
108 		dev_err(thc63->dev,
109 			"Failed to disable regulator \"vcc\": %d\n", ret);
110 }
111 
112 static const struct drm_bridge_funcs thc63_bridge_func = {
113 	.attach	= thc63_attach,
114 	.mode_valid = thc63_mode_valid,
115 	.enable = thc63_enable,
116 	.disable = thc63_disable,
117 };
118 
119 static int thc63_parse_dt(struct thc63_dev *thc63)
120 {
121 	struct device_node *endpoint;
122 	struct device_node *remote;
123 
124 	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
125 						 THC63_RGB_OUT0, -1);
126 	if (!endpoint) {
127 		dev_err(thc63->dev, "Missing endpoint in port@%u\n",
128 			THC63_RGB_OUT0);
129 		return -ENODEV;
130 	}
131 
132 	remote = of_graph_get_remote_port_parent(endpoint);
133 	of_node_put(endpoint);
134 	if (!remote) {
135 		dev_err(thc63->dev, "Endpoint in port@%u unconnected\n",
136 			THC63_RGB_OUT0);
137 		return -ENODEV;
138 	}
139 
140 	if (!of_device_is_available(remote)) {
141 		dev_err(thc63->dev, "port@%u remote endpoint is disabled\n",
142 			THC63_RGB_OUT0);
143 		of_node_put(remote);
144 		return -ENODEV;
145 	}
146 
147 	thc63->next = of_drm_find_bridge(remote);
148 	of_node_put(remote);
149 	if (!thc63->next)
150 		return -EPROBE_DEFER;
151 
152 	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
153 						 THC63_LVDS_IN1, -1);
154 	if (endpoint) {
155 		remote = of_graph_get_remote_port_parent(endpoint);
156 		of_node_put(endpoint);
157 
158 		if (remote) {
159 			if (of_device_is_available(remote))
160 				thc63->timings.dual_link = true;
161 			of_node_put(remote);
162 		}
163 	}
164 
165 	dev_dbg(thc63->dev, "operating in %s-link mode\n",
166 		thc63->timings.dual_link ? "dual" : "single");
167 
168 	return 0;
169 }
170 
171 static int thc63_gpio_init(struct thc63_dev *thc63)
172 {
173 	thc63->oe = devm_gpiod_get_optional(thc63->dev, "oe", GPIOD_OUT_LOW);
174 	if (IS_ERR(thc63->oe)) {
175 		dev_err(thc63->dev, "Unable to get \"oe-gpios\": %ld\n",
176 			PTR_ERR(thc63->oe));
177 		return PTR_ERR(thc63->oe);
178 	}
179 
180 	thc63->pdwn = devm_gpiod_get_optional(thc63->dev, "powerdown",
181 					      GPIOD_OUT_HIGH);
182 	if (IS_ERR(thc63->pdwn)) {
183 		dev_err(thc63->dev, "Unable to get \"powerdown-gpios\": %ld\n",
184 			PTR_ERR(thc63->pdwn));
185 		return PTR_ERR(thc63->pdwn);
186 	}
187 
188 	return 0;
189 }
190 
191 static int thc63_probe(struct platform_device *pdev)
192 {
193 	struct thc63_dev *thc63;
194 	int ret;
195 
196 	thc63 = devm_kzalloc(&pdev->dev, sizeof(*thc63), GFP_KERNEL);
197 	if (!thc63)
198 		return -ENOMEM;
199 
200 	thc63->dev = &pdev->dev;
201 	platform_set_drvdata(pdev, thc63);
202 
203 	thc63->vcc = devm_regulator_get_optional(thc63->dev, "vcc");
204 	if (IS_ERR(thc63->vcc)) {
205 		if (PTR_ERR(thc63->vcc) == -EPROBE_DEFER)
206 			return -EPROBE_DEFER;
207 
208 		dev_err(thc63->dev, "Unable to get \"vcc\" supply: %ld\n",
209 			PTR_ERR(thc63->vcc));
210 		return PTR_ERR(thc63->vcc);
211 	}
212 
213 	ret = thc63_gpio_init(thc63);
214 	if (ret)
215 		return ret;
216 
217 	ret = thc63_parse_dt(thc63);
218 	if (ret)
219 		return ret;
220 
221 	thc63->bridge.driver_private = thc63;
222 	thc63->bridge.of_node = pdev->dev.of_node;
223 	thc63->bridge.funcs = &thc63_bridge_func;
224 	thc63->bridge.timings = &thc63->timings;
225 
226 	drm_bridge_add(&thc63->bridge);
227 
228 	return 0;
229 }
230 
231 static int thc63_remove(struct platform_device *pdev)
232 {
233 	struct thc63_dev *thc63 = platform_get_drvdata(pdev);
234 
235 	drm_bridge_remove(&thc63->bridge);
236 
237 	return 0;
238 }
239 
240 static const struct of_device_id thc63_match[] = {
241 	{ .compatible = "thine,thc63lvd1024", },
242 	{ },
243 };
244 MODULE_DEVICE_TABLE(of, thc63_match);
245 
246 static struct platform_driver thc63_driver = {
247 	.probe	= thc63_probe,
248 	.remove	= thc63_remove,
249 	.driver	= {
250 		.name		= "thc63lvd1024",
251 		.of_match_table	= thc63_match,
252 	},
253 };
254 module_platform_driver(thc63_driver);
255 
256 MODULE_AUTHOR("Jacopo Mondi <jacopo@jmondi.org>");
257 MODULE_DESCRIPTION("Thine THC63LVD1024 LVDS decoder DRM bridge driver");
258 MODULE_LICENSE("GPL v2");
259