1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2020 Luca Weiss <luca@z3ntu.xyz>
3 
4 #include <linux/gpio/consumer.h>
5 #include <linux/led-class-flash.h>
6 #include <linux/module.h>
7 #include <linux/regulator/consumer.h>
8 #include <linux/platform_device.h>
9 
10 #include <media/v4l2-flash-led-class.h>
11 
12 #define FLASH_TIMEOUT_DEFAULT		250000U /* 250ms */
13 #define FLASH_MAX_TIMEOUT_DEFAULT	300000U /* 300ms */
14 
15 struct sgm3140 {
16 	struct led_classdev_flash fled_cdev;
17 	struct v4l2_flash *v4l2_flash;
18 
19 	struct timer_list powerdown_timer;
20 
21 	struct gpio_desc *flash_gpio;
22 	struct gpio_desc *enable_gpio;
23 	struct regulator *vin_regulator;
24 
25 	bool enabled;
26 
27 	/* current timeout in us */
28 	u32 timeout;
29 	/* maximum timeout in us */
30 	u32 max_timeout;
31 };
32 
33 static struct sgm3140 *flcdev_to_sgm3140(struct led_classdev_flash *flcdev)
34 {
35 	return container_of(flcdev, struct sgm3140, fled_cdev);
36 }
37 
38 static int sgm3140_strobe_set(struct led_classdev_flash *fled_cdev, bool state)
39 {
40 	struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
41 	int ret;
42 
43 	if (priv->enabled == state)
44 		return 0;
45 
46 	if (state) {
47 		ret = regulator_enable(priv->vin_regulator);
48 		if (ret) {
49 			dev_err(fled_cdev->led_cdev.dev,
50 				"failed to enable regulator: %d\n", ret);
51 			return ret;
52 		}
53 		gpiod_set_value_cansleep(priv->flash_gpio, 1);
54 		gpiod_set_value_cansleep(priv->enable_gpio, 1);
55 		mod_timer(&priv->powerdown_timer,
56 			  jiffies + usecs_to_jiffies(priv->timeout));
57 	} else {
58 		del_timer_sync(&priv->powerdown_timer);
59 		gpiod_set_value_cansleep(priv->enable_gpio, 0);
60 		gpiod_set_value_cansleep(priv->flash_gpio, 0);
61 		ret = regulator_disable(priv->vin_regulator);
62 		if (ret) {
63 			dev_err(fled_cdev->led_cdev.dev,
64 				"failed to disable regulator: %d\n", ret);
65 			return ret;
66 		}
67 	}
68 
69 	priv->enabled = state;
70 
71 	return 0;
72 }
73 
74 static int sgm3140_strobe_get(struct led_classdev_flash *fled_cdev, bool *state)
75 {
76 	struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
77 
78 	*state = timer_pending(&priv->powerdown_timer);
79 
80 	return 0;
81 }
82 
83 static int sgm3140_timeout_set(struct led_classdev_flash *fled_cdev,
84 			       u32 timeout)
85 {
86 	struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
87 
88 	priv->timeout = timeout;
89 
90 	return 0;
91 }
92 
93 static const struct led_flash_ops sgm3140_flash_ops = {
94 	.strobe_set = sgm3140_strobe_set,
95 	.strobe_get = sgm3140_strobe_get,
96 	.timeout_set = sgm3140_timeout_set,
97 };
98 
99 static int sgm3140_brightness_set(struct led_classdev *led_cdev,
100 				  enum led_brightness brightness)
101 {
102 	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
103 	struct sgm3140 *priv = flcdev_to_sgm3140(fled_cdev);
104 	bool enable = brightness == LED_ON;
105 	int ret;
106 
107 	if (priv->enabled == enable)
108 		return 0;
109 
110 	if (enable) {
111 		ret = regulator_enable(priv->vin_regulator);
112 		if (ret) {
113 			dev_err(led_cdev->dev,
114 				"failed to enable regulator: %d\n", ret);
115 			return ret;
116 		}
117 		gpiod_set_value_cansleep(priv->enable_gpio, 1);
118 	} else {
119 		gpiod_set_value_cansleep(priv->enable_gpio, 0);
120 		ret = regulator_disable(priv->vin_regulator);
121 		if (ret) {
122 			dev_err(led_cdev->dev,
123 				"failed to disable regulator: %d\n", ret);
124 			return ret;
125 		}
126 	}
127 
128 	priv->enabled = enable;
129 
130 	return 0;
131 }
132 
133 static void sgm3140_powerdown_timer(struct timer_list *t)
134 {
135 	struct sgm3140 *priv = from_timer(priv, t, powerdown_timer);
136 
137 	gpiod_set_value(priv->enable_gpio, 0);
138 	gpiod_set_value(priv->flash_gpio, 0);
139 	regulator_disable(priv->vin_regulator);
140 
141 	priv->enabled = false;
142 }
143 
144 static void sgm3140_init_flash_timeout(struct sgm3140 *priv)
145 {
146 	struct led_classdev_flash *fled_cdev = &priv->fled_cdev;
147 	struct led_flash_setting *s;
148 
149 	/* Init flash timeout setting */
150 	s = &fled_cdev->timeout;
151 	s->min = 1;
152 	s->max = priv->max_timeout;
153 	s->step = 1;
154 	s->val = FLASH_TIMEOUT_DEFAULT;
155 }
156 
157 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
158 static void sgm3140_init_v4l2_flash_config(struct sgm3140 *priv,
159 					struct v4l2_flash_config *v4l2_sd_cfg)
160 {
161 	struct led_classdev *led_cdev = &priv->fled_cdev.led_cdev;
162 	struct led_flash_setting *s;
163 
164 	strscpy(v4l2_sd_cfg->dev_name, led_cdev->dev->kobj.name,
165 		sizeof(v4l2_sd_cfg->dev_name));
166 
167 	/* Init flash intensity setting */
168 	s = &v4l2_sd_cfg->intensity;
169 	s->min = 0;
170 	s->max = 1;
171 	s->step = 1;
172 	s->val = 1;
173 }
174 
175 #else
176 static void sgm3140_init_v4l2_flash_config(struct sgm3140 *priv,
177 					struct v4l2_flash_config *v4l2_sd_cfg)
178 {
179 }
180 #endif
181 
182 static int sgm3140_probe(struct platform_device *pdev)
183 {
184 	struct sgm3140 *priv;
185 	struct led_classdev *led_cdev;
186 	struct led_classdev_flash *fled_cdev;
187 	struct led_init_data init_data = {};
188 	struct fwnode_handle *child_node;
189 	struct v4l2_flash_config v4l2_sd_cfg = {};
190 	int ret;
191 
192 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
193 	if (!priv)
194 		return -ENOMEM;
195 
196 	priv->flash_gpio = devm_gpiod_get(&pdev->dev, "flash", GPIOD_OUT_LOW);
197 	ret = PTR_ERR_OR_ZERO(priv->flash_gpio);
198 	if (ret)
199 		return dev_err_probe(&pdev->dev, ret,
200 				     "Failed to request flash gpio\n");
201 
202 	priv->enable_gpio = devm_gpiod_get(&pdev->dev, "enable", GPIOD_OUT_LOW);
203 	ret = PTR_ERR_OR_ZERO(priv->enable_gpio);
204 	if (ret)
205 		return dev_err_probe(&pdev->dev, ret,
206 				     "Failed to request enable gpio\n");
207 
208 	priv->vin_regulator = devm_regulator_get(&pdev->dev, "vin");
209 	ret = PTR_ERR_OR_ZERO(priv->vin_regulator);
210 	if (ret)
211 		return dev_err_probe(&pdev->dev, ret,
212 				     "Failed to request regulator\n");
213 
214 	child_node = fwnode_get_next_available_child_node(pdev->dev.fwnode,
215 							  NULL);
216 	if (!child_node) {
217 		dev_err(&pdev->dev,
218 			"No fwnode child node found for connected LED.\n");
219 		return -EINVAL;
220 	}
221 
222 	ret = fwnode_property_read_u32(child_node, "flash-max-timeout-us",
223 				       &priv->max_timeout);
224 	if (ret) {
225 		priv->max_timeout = FLASH_MAX_TIMEOUT_DEFAULT;
226 		dev_warn(&pdev->dev,
227 			 "flash-max-timeout-us property missing\n");
228 	}
229 
230 	/*
231 	 * Set default timeout to FLASH_DEFAULT_TIMEOUT except if max_timeout
232 	 * from DT is lower.
233 	 */
234 	priv->timeout = min(priv->max_timeout, FLASH_TIMEOUT_DEFAULT);
235 
236 	timer_setup(&priv->powerdown_timer, sgm3140_powerdown_timer, 0);
237 
238 	fled_cdev = &priv->fled_cdev;
239 	led_cdev = &fled_cdev->led_cdev;
240 
241 	fled_cdev->ops = &sgm3140_flash_ops;
242 
243 	led_cdev->brightness_set_blocking = sgm3140_brightness_set;
244 	led_cdev->max_brightness = LED_ON;
245 	led_cdev->flags |= LED_DEV_CAP_FLASH;
246 
247 	sgm3140_init_flash_timeout(priv);
248 
249 	init_data.fwnode = child_node;
250 
251 	platform_set_drvdata(pdev, priv);
252 
253 	/* Register in the LED subsystem */
254 	ret = devm_led_classdev_flash_register_ext(&pdev->dev,
255 						   fled_cdev, &init_data);
256 	if (ret) {
257 		dev_err(&pdev->dev, "Failed to register flash device: %d\n",
258 			ret);
259 		goto err;
260 	}
261 
262 	sgm3140_init_v4l2_flash_config(priv, &v4l2_sd_cfg);
263 
264 	/* Create V4L2 Flash subdev */
265 	priv->v4l2_flash = v4l2_flash_init(&pdev->dev,
266 					   child_node,
267 					   fled_cdev, NULL,
268 					   &v4l2_sd_cfg);
269 	if (IS_ERR(priv->v4l2_flash)) {
270 		ret = PTR_ERR(priv->v4l2_flash);
271 		goto err;
272 	}
273 
274 	return ret;
275 
276 err:
277 	fwnode_handle_put(child_node);
278 	return ret;
279 }
280 
281 static int sgm3140_remove(struct platform_device *pdev)
282 {
283 	struct sgm3140 *priv = platform_get_drvdata(pdev);
284 
285 	del_timer_sync(&priv->powerdown_timer);
286 
287 	v4l2_flash_release(priv->v4l2_flash);
288 
289 	return 0;
290 }
291 
292 static const struct of_device_id sgm3140_dt_match[] = {
293 	{ .compatible = "sgmicro,sgm3140" },
294 	{ /* sentinel */ }
295 };
296 MODULE_DEVICE_TABLE(of, sgm3140_dt_match);
297 
298 static struct platform_driver sgm3140_driver = {
299 	.probe	= sgm3140_probe,
300 	.remove	= sgm3140_remove,
301 	.driver	= {
302 		.name	= "sgm3140",
303 		.of_match_table = sgm3140_dt_match,
304 	},
305 };
306 
307 module_platform_driver(sgm3140_driver);
308 
309 MODULE_AUTHOR("Luca Weiss <luca@z3ntu.xyz>");
310 MODULE_DESCRIPTION("SG Micro SGM3140 charge pump LED driver");
311 MODULE_LICENSE("GPL v2");
312