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Vasant Hegde84ad6e52015-08-19 22:19:54 +05301/*
2 * PowerNV LED Driver
3 *
4 * Copyright IBM Corp. 2015
5 *
6 * Author: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
7 * Author: Anshuman Khandual <khandual@linux.vnet.ibm.com>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14
15#include <linux/leds.h>
16#include <linux/module.h>
17#include <linux/of.h>
18#include <linux/platform_device.h>
19#include <linux/slab.h>
20#include <linux/types.h>
21
22#include <asm/opal.h>
23
24/* Map LED type to description. */
25struct led_type_map {
26 const int type;
27 const char *desc;
28};
29static const struct led_type_map led_type_map[] = {
Michael Ellerman5d53be72015-08-22 09:33:55 +100030 {OPAL_SLOT_LED_TYPE_ID, "identify"},
31 {OPAL_SLOT_LED_TYPE_FAULT, "fault"},
32 {OPAL_SLOT_LED_TYPE_ATTN, "attention"},
Vasant Hegde84ad6e52015-08-19 22:19:54 +053033 {-1, NULL},
34};
35
36struct powernv_led_common {
37 /*
38 * By default unload path resets all the LEDs. But on PowerNV
39 * platform we want to retain LED state across reboot as these
40 * are controlled by firmware. Also service processor can modify
41 * the LEDs independent of OS. Hence avoid resetting LEDs in
42 * unload path.
43 */
44 bool led_disabled;
45
46 /* Max supported LED type */
47 __be64 max_led_type;
48
49 /* glabal lock */
50 struct mutex lock;
51};
52
53/* PowerNV LED data */
54struct powernv_led_data {
55 struct led_classdev cdev;
56 char *loc_code; /* LED location code */
57 int led_type; /* OPAL_SLOT_LED_TYPE_* */
58
59 struct powernv_led_common *common;
60};
61
62
63/* Returns OPAL_SLOT_LED_TYPE_* for given led type string */
64static int powernv_get_led_type(const char *led_type_desc)
65{
66 int i;
67
68 for (i = 0; i < ARRAY_SIZE(led_type_map); i++)
69 if (!strcmp(led_type_map[i].desc, led_type_desc))
70 return led_type_map[i].type;
71
72 return -1;
73}
74
75/*
76 * This commits the state change of the requested LED through an OPAL call.
77 * This function is called from work queue task context when ever it gets
78 * scheduled. This function can sleep at opal_async_wait_response call.
79 */
80static void powernv_led_set(struct powernv_led_data *powernv_led,
81 enum led_brightness value)
82{
83 int rc, token;
84 u64 led_mask, led_value = 0;
85 __be64 max_type;
86 struct opal_msg msg;
87 struct device *dev = powernv_led->cdev.dev;
88 struct powernv_led_common *powernv_led_common = powernv_led->common;
89
90 /* Prepare for the OPAL call */
91 max_type = powernv_led_common->max_led_type;
92 led_mask = OPAL_SLOT_LED_STATE_ON << powernv_led->led_type;
93 if (value)
94 led_value = led_mask;
95
96 /* OPAL async call */
97 token = opal_async_get_token_interruptible();
98 if (token < 0) {
99 if (token != -ERESTARTSYS)
100 dev_err(dev, "%s: Couldn't get OPAL async token\n",
101 __func__);
102 return;
103 }
104
105 rc = opal_leds_set_ind(token, powernv_led->loc_code,
106 led_mask, led_value, &max_type);
107 if (rc != OPAL_ASYNC_COMPLETION) {
108 dev_err(dev, "%s: OPAL set LED call failed for %s [rc=%d]\n",
109 __func__, powernv_led->loc_code, rc);
110 goto out_token;
111 }
112
113 rc = opal_async_wait_response(token, &msg);
114 if (rc) {
115 dev_err(dev,
116 "%s: Failed to wait for the async response [rc=%d]\n",
117 __func__, rc);
118 goto out_token;
119 }
120
121 rc = be64_to_cpu(msg.params[1]);
122 if (rc != OPAL_SUCCESS)
123 dev_err(dev, "%s : OAPL async call returned failed [rc=%d]\n",
124 __func__, rc);
125
126out_token:
127 opal_async_release_token(token);
128}
129
130/*
131 * This function fetches the LED state for a given LED type for
132 * mentioned LED classdev structure.
133 */
134static enum led_brightness powernv_led_get(struct powernv_led_data *powernv_led)
135{
136 int rc;
137 __be64 mask, value, max_type;
138 u64 led_mask, led_value;
139 struct device *dev = powernv_led->cdev.dev;
140 struct powernv_led_common *powernv_led_common = powernv_led->common;
141
142 /* Fetch all LED status */
143 mask = cpu_to_be64(0);
144 value = cpu_to_be64(0);
145 max_type = powernv_led_common->max_led_type;
146
147 rc = opal_leds_get_ind(powernv_led->loc_code,
148 &mask, &value, &max_type);
149 if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
150 dev_err(dev, "%s: OPAL get led call failed [rc=%d]\n",
151 __func__, rc);
152 return LED_OFF;
153 }
154
155 led_mask = be64_to_cpu(mask);
156 led_value = be64_to_cpu(value);
157
158 /* LED status available */
159 if (!((led_mask >> powernv_led->led_type) & OPAL_SLOT_LED_STATE_ON)) {
160 dev_err(dev, "%s: LED status not available for %s\n",
161 __func__, powernv_led->cdev.name);
162 return LED_OFF;
163 }
164
165 /* LED status value */
166 if ((led_value >> powernv_led->led_type) & OPAL_SLOT_LED_STATE_ON)
167 return LED_FULL;
168
169 return LED_OFF;
170}
171
172/*
173 * LED classdev 'brightness_get' function. This schedules work
174 * to update LED state.
175 */
176static void powernv_brightness_set(struct led_classdev *led_cdev,
177 enum led_brightness value)
178{
179 struct powernv_led_data *powernv_led =
180 container_of(led_cdev, struct powernv_led_data, cdev);
181 struct powernv_led_common *powernv_led_common = powernv_led->common;
182
183 /* Do not modify LED in unload path */
184 if (powernv_led_common->led_disabled)
185 return;
186
187 mutex_lock(&powernv_led_common->lock);
188 powernv_led_set(powernv_led, value);
189 mutex_unlock(&powernv_led_common->lock);
190}
191
192/* LED classdev 'brightness_get' function */
193static enum led_brightness powernv_brightness_get(struct led_classdev *led_cdev)
194{
195 struct powernv_led_data *powernv_led =
196 container_of(led_cdev, struct powernv_led_data, cdev);
197
198 return powernv_led_get(powernv_led);
199}
200
201/*
202 * This function registers classdev structure for any given type of LED on
203 * a given child LED device node.
204 */
205static int powernv_led_create(struct device *dev,
206 struct powernv_led_data *powernv_led,
207 const char *led_type_desc)
208{
209 int rc;
210
211 /* Make sure LED type is supported */
212 powernv_led->led_type = powernv_get_led_type(led_type_desc);
213 if (powernv_led->led_type == -1) {
214 dev_warn(dev, "%s: No support for led type : %s\n",
215 __func__, led_type_desc);
216 return -EINVAL;
217 }
218
219 /* Create the name for classdev */
220 powernv_led->cdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s:%s",
221 powernv_led->loc_code,
222 led_type_desc);
223 if (!powernv_led->cdev.name) {
224 dev_err(dev,
225 "%s: Memory allocation failed for classdev name\n",
226 __func__);
227 return -ENOMEM;
228 }
229
230 powernv_led->cdev.brightness_set = powernv_brightness_set;
231 powernv_led->cdev.brightness_get = powernv_brightness_get;
232 powernv_led->cdev.brightness = LED_OFF;
233 powernv_led->cdev.max_brightness = LED_FULL;
234
235 /* Register the classdev */
236 rc = devm_led_classdev_register(dev, &powernv_led->cdev);
237 if (rc) {
238 dev_err(dev, "%s: Classdev registration failed for %s\n",
239 __func__, powernv_led->cdev.name);
240 }
241
242 return rc;
243}
244
245/* Go through LED device tree node and register LED classdev structure */
246static int powernv_led_classdev(struct platform_device *pdev,
247 struct device_node *led_node,
248 struct powernv_led_common *powernv_led_common)
249{
250 const char *cur = NULL;
251 int rc = -1;
252 struct property *p;
253 struct device_node *np;
254 struct powernv_led_data *powernv_led;
255 struct device *dev = &pdev->dev;
256
257 for_each_child_of_node(led_node, np) {
258 p = of_find_property(np, "led-types", NULL);
259 if (!p)
260 continue;
261
262 while ((cur = of_prop_next_string(p, cur)) != NULL) {
263 powernv_led = devm_kzalloc(dev, sizeof(*powernv_led),
264 GFP_KERNEL);
Julia Lawalldde4afe2015-10-24 16:42:27 +0200265 if (!powernv_led) {
266 of_node_put(np);
Vasant Hegde84ad6e52015-08-19 22:19:54 +0530267 return -ENOMEM;
Julia Lawalldde4afe2015-10-24 16:42:27 +0200268 }
Vasant Hegde84ad6e52015-08-19 22:19:54 +0530269
270 powernv_led->common = powernv_led_common;
271 powernv_led->loc_code = (char *)np->name;
272
273 rc = powernv_led_create(dev, powernv_led, cur);
Julia Lawalldde4afe2015-10-24 16:42:27 +0200274 if (rc) {
275 of_node_put(np);
Vasant Hegde84ad6e52015-08-19 22:19:54 +0530276 return rc;
Julia Lawalldde4afe2015-10-24 16:42:27 +0200277 }
Vasant Hegde84ad6e52015-08-19 22:19:54 +0530278 } /* while end */
279 }
280
281 return rc;
282}
283
284/* Platform driver probe */
285static int powernv_led_probe(struct platform_device *pdev)
286{
287 struct device_node *led_node;
288 struct powernv_led_common *powernv_led_common;
289 struct device *dev = &pdev->dev;
290
291 led_node = of_find_node_by_path("/ibm,opal/leds");
292 if (!led_node) {
293 dev_err(dev, "%s: LED parent device node not found\n",
294 __func__);
295 return -EINVAL;
296 }
297
298 powernv_led_common = devm_kzalloc(dev, sizeof(*powernv_led_common),
299 GFP_KERNEL);
300 if (!powernv_led_common)
301 return -ENOMEM;
302
303 mutex_init(&powernv_led_common->lock);
304 powernv_led_common->max_led_type = cpu_to_be64(OPAL_SLOT_LED_TYPE_MAX);
305
306 platform_set_drvdata(pdev, powernv_led_common);
307
308 return powernv_led_classdev(pdev, led_node, powernv_led_common);
309}
310
311/* Platform driver remove */
312static int powernv_led_remove(struct platform_device *pdev)
313{
314 struct powernv_led_common *powernv_led_common;
315
316 /* Disable LED operation */
317 powernv_led_common = platform_get_drvdata(pdev);
318 powernv_led_common->led_disabled = true;
319
320 /* Destroy lock */
321 mutex_destroy(&powernv_led_common->lock);
322
323 dev_info(&pdev->dev, "PowerNV led module unregistered\n");
324 return 0;
325}
326
327/* Platform driver property match */
328static const struct of_device_id powernv_led_match[] = {
329 {
330 .compatible = "ibm,opal-v3-led",
331 },
332 {},
333};
334MODULE_DEVICE_TABLE(of, powernv_led_match);
335
336static struct platform_driver powernv_led_driver = {
337 .probe = powernv_led_probe,
338 .remove = powernv_led_remove,
339 .driver = {
340 .name = "powernv-led-driver",
341 .of_match_table = powernv_led_match,
342 },
343};
344
345module_platform_driver(powernv_led_driver);
346
347MODULE_LICENSE("GPL v2");
348MODULE_DESCRIPTION("PowerNV LED driver");
349MODULE_AUTHOR("Vasant Hegde <hegdevasant@linux.vnet.ibm.com>");