xref: /openbmc/linux/drivers/leds/leds-ns2.c (revision 3ddc8b84)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * leds-ns2.c - Driver for the Network Space v2 (and parents) dual-GPIO LED
4  *
5  * Copyright (C) 2010 LaCie
6  *
7  * Author: Simon Guinot <sguinot@lacie.com>
8  *
9  * Based on leds-gpio.c by Raphael Assenat <raph@8d.com>
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/platform_device.h>
14 #include <linux/slab.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/leds.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include "leds.h"
20 
21 enum ns2_led_modes {
22 	NS_V2_LED_OFF,
23 	NS_V2_LED_ON,
24 	NS_V2_LED_SATA,
25 };
26 
27 /*
28  * If the size of this structure or types of its members is changed,
29  * the filling of array modval in function ns2_led_register must be changed
30  * accordingly.
31  */
32 struct ns2_led_modval {
33 	u32			mode;
34 	u32			cmd_level;
35 	u32			slow_level;
36 } __packed;
37 
38 /*
39  * The Network Space v2 dual-GPIO LED is wired to a CPLD. Three different LED
40  * modes are available: off, on and SATA activity blinking. The LED modes are
41  * controlled through two GPIOs (command and slow): each combination of values
42  * for the command/slow GPIOs corresponds to a LED mode.
43  */
44 
45 struct ns2_led {
46 	struct led_classdev	cdev;
47 	struct gpio_desc	*cmd;
48 	struct gpio_desc	*slow;
49 	bool			can_sleep;
50 	unsigned char		sata; /* True when SATA mode active. */
51 	rwlock_t		rw_lock; /* Lock GPIOs. */
52 	int			num_modes;
53 	struct ns2_led_modval	*modval;
54 };
55 
56 static int ns2_led_get_mode(struct ns2_led *led, enum ns2_led_modes *mode)
57 {
58 	int i;
59 	int cmd_level;
60 	int slow_level;
61 
62 	cmd_level = gpiod_get_value_cansleep(led->cmd);
63 	slow_level = gpiod_get_value_cansleep(led->slow);
64 
65 	for (i = 0; i < led->num_modes; i++) {
66 		if (cmd_level == led->modval[i].cmd_level &&
67 		    slow_level == led->modval[i].slow_level) {
68 			*mode = led->modval[i].mode;
69 			return 0;
70 		}
71 	}
72 
73 	return -EINVAL;
74 }
75 
76 static void ns2_led_set_mode(struct ns2_led *led, enum ns2_led_modes mode)
77 {
78 	int i;
79 	unsigned long flags;
80 
81 	for (i = 0; i < led->num_modes; i++)
82 		if (mode == led->modval[i].mode)
83 			break;
84 
85 	if (i == led->num_modes)
86 		return;
87 
88 	write_lock_irqsave(&led->rw_lock, flags);
89 
90 	if (!led->can_sleep) {
91 		gpiod_set_value(led->cmd, led->modval[i].cmd_level);
92 		gpiod_set_value(led->slow, led->modval[i].slow_level);
93 		goto exit_unlock;
94 	}
95 
96 	gpiod_set_value_cansleep(led->cmd, led->modval[i].cmd_level);
97 	gpiod_set_value_cansleep(led->slow, led->modval[i].slow_level);
98 
99 exit_unlock:
100 	write_unlock_irqrestore(&led->rw_lock, flags);
101 }
102 
103 static void ns2_led_set(struct led_classdev *led_cdev,
104 			enum led_brightness value)
105 {
106 	struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
107 	enum ns2_led_modes mode;
108 
109 	if (value == LED_OFF)
110 		mode = NS_V2_LED_OFF;
111 	else if (led->sata)
112 		mode = NS_V2_LED_SATA;
113 	else
114 		mode = NS_V2_LED_ON;
115 
116 	ns2_led_set_mode(led, mode);
117 }
118 
119 static int ns2_led_set_blocking(struct led_classdev *led_cdev,
120 			enum led_brightness value)
121 {
122 	ns2_led_set(led_cdev, value);
123 	return 0;
124 }
125 
126 static ssize_t ns2_led_sata_store(struct device *dev,
127 				  struct device_attribute *attr,
128 				  const char *buff, size_t count)
129 {
130 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
131 	struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
132 	int ret;
133 	unsigned long enable;
134 
135 	ret = kstrtoul(buff, 10, &enable);
136 	if (ret < 0)
137 		return ret;
138 
139 	enable = !!enable;
140 
141 	if (led->sata == enable)
142 		goto exit;
143 
144 	led->sata = enable;
145 
146 	if (!led_get_brightness(led_cdev))
147 		goto exit;
148 
149 	if (enable)
150 		ns2_led_set_mode(led, NS_V2_LED_SATA);
151 	else
152 		ns2_led_set_mode(led, NS_V2_LED_ON);
153 
154 exit:
155 	return count;
156 }
157 
158 static ssize_t ns2_led_sata_show(struct device *dev,
159 				 struct device_attribute *attr, char *buf)
160 {
161 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
162 	struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
163 
164 	return sprintf(buf, "%d\n", led->sata);
165 }
166 
167 static DEVICE_ATTR(sata, 0644, ns2_led_sata_show, ns2_led_sata_store);
168 
169 static struct attribute *ns2_led_attrs[] = {
170 	&dev_attr_sata.attr,
171 	NULL
172 };
173 ATTRIBUTE_GROUPS(ns2_led);
174 
175 static int ns2_led_register(struct device *dev, struct fwnode_handle *node,
176 			    struct ns2_led *led)
177 {
178 	struct led_init_data init_data = {};
179 	struct ns2_led_modval *modval;
180 	enum ns2_led_modes mode;
181 	int nmodes, ret;
182 
183 	led->cmd = devm_fwnode_gpiod_get_index(dev, node, "cmd", 0, GPIOD_ASIS,
184 					       fwnode_get_name(node));
185 	if (IS_ERR(led->cmd))
186 		return PTR_ERR(led->cmd);
187 
188 	led->slow = devm_fwnode_gpiod_get_index(dev, node, "slow", 0,
189 						GPIOD_ASIS,
190 						fwnode_get_name(node));
191 	if (IS_ERR(led->slow))
192 		return PTR_ERR(led->slow);
193 
194 	ret = fwnode_property_count_u32(node, "modes-map");
195 	if (ret < 0 || ret % 3) {
196 		dev_err(dev, "Missing or malformed modes-map for %pfw\n", node);
197 		return -EINVAL;
198 	}
199 
200 	nmodes = ret / 3;
201 	modval = devm_kcalloc(dev, nmodes, sizeof(*modval), GFP_KERNEL);
202 	if (!modval)
203 		return -ENOMEM;
204 
205 	fwnode_property_read_u32_array(node, "modes-map", (void *)modval,
206 				       nmodes * 3);
207 
208 	rwlock_init(&led->rw_lock);
209 
210 	led->cdev.blink_set = NULL;
211 	led->cdev.flags |= LED_CORE_SUSPENDRESUME;
212 	led->cdev.groups = ns2_led_groups;
213 	led->can_sleep = gpiod_cansleep(led->cmd) || gpiod_cansleep(led->slow);
214 	if (led->can_sleep)
215 		led->cdev.brightness_set_blocking = ns2_led_set_blocking;
216 	else
217 		led->cdev.brightness_set = ns2_led_set;
218 	led->num_modes = nmodes;
219 	led->modval = modval;
220 
221 	ret = ns2_led_get_mode(led, &mode);
222 	if (ret < 0)
223 		return ret;
224 
225 	/* Set LED initial state. */
226 	led->sata = (mode == NS_V2_LED_SATA) ? 1 : 0;
227 	led->cdev.brightness = (mode == NS_V2_LED_OFF) ? LED_OFF : LED_FULL;
228 
229 	init_data.fwnode = node;
230 
231 	ret = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
232 	if (ret)
233 		dev_err(dev, "Failed to register LED for node %pfw\n", node);
234 
235 	return ret;
236 }
237 
238 static int ns2_led_probe(struct platform_device *pdev)
239 {
240 	struct device *dev = &pdev->dev;
241 	struct fwnode_handle *child;
242 	struct ns2_led *leds;
243 	int count;
244 	int ret;
245 
246 	count = device_get_child_node_count(dev);
247 	if (!count)
248 		return -ENODEV;
249 
250 	leds = devm_kcalloc(dev, count, sizeof(*leds), GFP_KERNEL);
251 	if (!leds)
252 		return -ENOMEM;
253 
254 	device_for_each_child_node(dev, child) {
255 		ret = ns2_led_register(dev, child, leds++);
256 		if (ret) {
257 			fwnode_handle_put(child);
258 			return ret;
259 		}
260 	}
261 
262 	return 0;
263 }
264 
265 static const struct of_device_id of_ns2_leds_match[] = {
266 	{ .compatible = "lacie,ns2-leds", },
267 	{},
268 };
269 MODULE_DEVICE_TABLE(of, of_ns2_leds_match);
270 
271 static struct platform_driver ns2_led_driver = {
272 	.probe		= ns2_led_probe,
273 	.driver		= {
274 		.name		= "leds-ns2",
275 		.of_match_table	= of_ns2_leds_match,
276 	},
277 };
278 
279 module_platform_driver(ns2_led_driver);
280 
281 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
282 MODULE_DESCRIPTION("Network Space v2 LED driver");
283 MODULE_LICENSE("GPL");
284 MODULE_ALIAS("platform:leds-ns2");
285