xref: /openbmc/linux/drivers/gpu/drm/msm/hdmi/hdmi_hpd.c (revision 77423a62)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2013 Red Hat
4  * Author: Rob Clark <robdclark@gmail.com>
5  */
6 
7 #include <linux/delay.h>
8 #include <linux/gpio/consumer.h>
9 #include <linux/pinctrl/consumer.h>
10 
11 #include "msm_kms.h"
12 #include "hdmi.h"
13 
14 static void msm_hdmi_phy_reset(struct hdmi *hdmi)
15 {
16 	unsigned int val;
17 
18 	val = hdmi_read(hdmi, REG_HDMI_PHY_CTRL);
19 
20 	if (val & HDMI_PHY_CTRL_SW_RESET_LOW) {
21 		/* pull low */
22 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
23 				val & ~HDMI_PHY_CTRL_SW_RESET);
24 	} else {
25 		/* pull high */
26 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
27 				val | HDMI_PHY_CTRL_SW_RESET);
28 	}
29 
30 	if (val & HDMI_PHY_CTRL_SW_RESET_PLL_LOW) {
31 		/* pull low */
32 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
33 				val & ~HDMI_PHY_CTRL_SW_RESET_PLL);
34 	} else {
35 		/* pull high */
36 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
37 				val | HDMI_PHY_CTRL_SW_RESET_PLL);
38 	}
39 
40 	msleep(100);
41 
42 	if (val & HDMI_PHY_CTRL_SW_RESET_LOW) {
43 		/* pull high */
44 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
45 				val | HDMI_PHY_CTRL_SW_RESET);
46 	} else {
47 		/* pull low */
48 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
49 				val & ~HDMI_PHY_CTRL_SW_RESET);
50 	}
51 
52 	if (val & HDMI_PHY_CTRL_SW_RESET_PLL_LOW) {
53 		/* pull high */
54 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
55 				val | HDMI_PHY_CTRL_SW_RESET_PLL);
56 	} else {
57 		/* pull low */
58 		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
59 				val & ~HDMI_PHY_CTRL_SW_RESET_PLL);
60 	}
61 }
62 
63 static void enable_hpd_clocks(struct hdmi *hdmi, bool enable)
64 {
65 	const struct hdmi_platform_config *config = hdmi->config;
66 	struct device *dev = &hdmi->pdev->dev;
67 	int i, ret;
68 
69 	if (enable) {
70 		for (i = 0; i < config->hpd_clk_cnt; i++) {
71 			if (config->hpd_freq && config->hpd_freq[i]) {
72 				ret = clk_set_rate(hdmi->hpd_clks[i],
73 						   config->hpd_freq[i]);
74 				if (ret)
75 					dev_warn(dev,
76 						 "failed to set clk %s (%d)\n",
77 						 config->hpd_clk_names[i], ret);
78 			}
79 
80 			ret = clk_prepare_enable(hdmi->hpd_clks[i]);
81 			if (ret) {
82 				DRM_DEV_ERROR(dev,
83 					"failed to enable hpd clk: %s (%d)\n",
84 					config->hpd_clk_names[i], ret);
85 			}
86 		}
87 	} else {
88 		for (i = config->hpd_clk_cnt - 1; i >= 0; i--)
89 			clk_disable_unprepare(hdmi->hpd_clks[i]);
90 	}
91 }
92 
93 int msm_hdmi_hpd_enable(struct drm_bridge *bridge)
94 {
95 	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
96 	struct hdmi *hdmi = hdmi_bridge->hdmi;
97 	const struct hdmi_platform_config *config = hdmi->config;
98 	struct device *dev = &hdmi->pdev->dev;
99 	uint32_t hpd_ctrl;
100 	int ret;
101 	unsigned long flags;
102 
103 	ret = regulator_bulk_enable(config->hpd_reg_cnt, hdmi->hpd_regs);
104 	if (ret) {
105 		DRM_DEV_ERROR(dev, "failed to enable hpd regulators: %d\n", ret);
106 		goto fail;
107 	}
108 
109 	ret = pinctrl_pm_select_default_state(dev);
110 	if (ret) {
111 		DRM_DEV_ERROR(dev, "pinctrl state chg failed: %d\n", ret);
112 		goto fail;
113 	}
114 
115 	if (hdmi->hpd_gpiod)
116 		gpiod_set_value_cansleep(hdmi->hpd_gpiod, 1);
117 
118 	pm_runtime_get_sync(dev);
119 	enable_hpd_clocks(hdmi, true);
120 
121 	msm_hdmi_set_mode(hdmi, false);
122 	msm_hdmi_phy_reset(hdmi);
123 	msm_hdmi_set_mode(hdmi, true);
124 
125 	hdmi_write(hdmi, REG_HDMI_USEC_REFTIMER, 0x0001001b);
126 
127 	/* enable HPD events: */
128 	hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL,
129 			HDMI_HPD_INT_CTRL_INT_CONNECT |
130 			HDMI_HPD_INT_CTRL_INT_EN);
131 
132 	/* set timeout to 4.1ms (max) for hardware debounce */
133 	spin_lock_irqsave(&hdmi->reg_lock, flags);
134 	hpd_ctrl = hdmi_read(hdmi, REG_HDMI_HPD_CTRL);
135 	hpd_ctrl |= HDMI_HPD_CTRL_TIMEOUT(0x1fff);
136 
137 	/* Toggle HPD circuit to trigger HPD sense */
138 	hdmi_write(hdmi, REG_HDMI_HPD_CTRL,
139 			~HDMI_HPD_CTRL_ENABLE & hpd_ctrl);
140 	hdmi_write(hdmi, REG_HDMI_HPD_CTRL,
141 			HDMI_HPD_CTRL_ENABLE | hpd_ctrl);
142 	spin_unlock_irqrestore(&hdmi->reg_lock, flags);
143 
144 	return 0;
145 
146 fail:
147 	return ret;
148 }
149 
150 void msm_hdmi_hpd_disable(struct hdmi_bridge *hdmi_bridge)
151 {
152 	struct hdmi *hdmi = hdmi_bridge->hdmi;
153 	const struct hdmi_platform_config *config = hdmi->config;
154 	struct device *dev = &hdmi->pdev->dev;
155 	int ret;
156 
157 	/* Disable HPD interrupt */
158 	hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL, 0);
159 
160 	msm_hdmi_set_mode(hdmi, false);
161 
162 	enable_hpd_clocks(hdmi, false);
163 	pm_runtime_put(dev);
164 
165 	ret = pinctrl_pm_select_sleep_state(dev);
166 	if (ret)
167 		dev_warn(dev, "pinctrl state chg failed: %d\n", ret);
168 
169 	ret = regulator_bulk_disable(config->hpd_reg_cnt, hdmi->hpd_regs);
170 	if (ret)
171 		dev_warn(dev, "failed to disable hpd regulator: %d\n", ret);
172 }
173 
174 void msm_hdmi_hpd_irq(struct drm_bridge *bridge)
175 {
176 	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
177 	struct hdmi *hdmi = hdmi_bridge->hdmi;
178 	uint32_t hpd_int_status, hpd_int_ctrl;
179 
180 	/* Process HPD: */
181 	hpd_int_status = hdmi_read(hdmi, REG_HDMI_HPD_INT_STATUS);
182 	hpd_int_ctrl   = hdmi_read(hdmi, REG_HDMI_HPD_INT_CTRL);
183 
184 	if ((hpd_int_ctrl & HDMI_HPD_INT_CTRL_INT_EN) &&
185 			(hpd_int_status & HDMI_HPD_INT_STATUS_INT)) {
186 		bool detected = !!(hpd_int_status & HDMI_HPD_INT_STATUS_CABLE_DETECTED);
187 
188 		/* ack & disable (temporarily) HPD events: */
189 		hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL,
190 			HDMI_HPD_INT_CTRL_INT_ACK);
191 
192 		DBG("status=%04x, ctrl=%04x", hpd_int_status, hpd_int_ctrl);
193 
194 		/* detect disconnect if we are connected or visa versa: */
195 		hpd_int_ctrl = HDMI_HPD_INT_CTRL_INT_EN;
196 		if (!detected)
197 			hpd_int_ctrl |= HDMI_HPD_INT_CTRL_INT_CONNECT;
198 		hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL, hpd_int_ctrl);
199 
200 		queue_work(hdmi->workq, &hdmi_bridge->hpd_work);
201 	}
202 }
203 
204 static enum drm_connector_status detect_reg(struct hdmi *hdmi)
205 {
206 	uint32_t hpd_int_status;
207 
208 	pm_runtime_get_sync(&hdmi->pdev->dev);
209 	enable_hpd_clocks(hdmi, true);
210 
211 	hpd_int_status = hdmi_read(hdmi, REG_HDMI_HPD_INT_STATUS);
212 
213 	enable_hpd_clocks(hdmi, false);
214 	pm_runtime_put(&hdmi->pdev->dev);
215 
216 	return (hpd_int_status & HDMI_HPD_INT_STATUS_CABLE_DETECTED) ?
217 			connector_status_connected : connector_status_disconnected;
218 }
219 
220 #define HPD_GPIO_INDEX	2
221 static enum drm_connector_status detect_gpio(struct hdmi *hdmi)
222 {
223 	return gpiod_get_value(hdmi->hpd_gpiod) ?
224 			connector_status_connected :
225 			connector_status_disconnected;
226 }
227 
228 enum drm_connector_status msm_hdmi_bridge_detect(
229 		struct drm_bridge *bridge)
230 {
231 	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
232 	struct hdmi *hdmi = hdmi_bridge->hdmi;
233 	enum drm_connector_status stat_gpio, stat_reg;
234 	int retry = 20;
235 
236 	/*
237 	 * some platforms may not have hpd gpio. Rely only on the status
238 	 * provided by REG_HDMI_HPD_INT_STATUS in this case.
239 	 */
240 	if (!hdmi->hpd_gpiod)
241 		return detect_reg(hdmi);
242 
243 	do {
244 		stat_gpio = detect_gpio(hdmi);
245 		stat_reg  = detect_reg(hdmi);
246 
247 		if (stat_gpio == stat_reg)
248 			break;
249 
250 		mdelay(10);
251 	} while (--retry);
252 
253 	/* the status we get from reading gpio seems to be more reliable,
254 	 * so trust that one the most if we didn't manage to get hdmi and
255 	 * gpio status to agree:
256 	 */
257 	if (stat_gpio != stat_reg) {
258 		DBG("HDMI_HPD_INT_STATUS tells us: %d", stat_reg);
259 		DBG("hpd gpio tells us: %d", stat_gpio);
260 	}
261 
262 	return stat_gpio;
263 }
264