1 /*
2  * PowerNV sensor code
3  *
4  * Copyright (C) 2013 IBM
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 
21 #include <linux/delay.h>
22 #include <linux/mutex.h>
23 #include <linux/of_platform.h>
24 #include <asm/opal.h>
25 #include <asm/machdep.h>
26 
27 static DEFINE_MUTEX(opal_sensor_mutex);
28 
29 /*
30  * This will return sensor information to driver based on the requested sensor
31  * handle. A handle is an opaque id for the powernv, read by the driver from the
32  * device tree..
33  */
34 int opal_get_sensor_data(u32 sensor_hndl, u32 *sensor_data)
35 {
36 	int ret, token;
37 	struct opal_msg msg;
38 	__be32 data;
39 
40 	token = opal_async_get_token_interruptible();
41 	if (token < 0) {
42 		pr_err("%s: Couldn't get the token, returning\n", __func__);
43 		ret = token;
44 		goto out;
45 	}
46 
47 	mutex_lock(&opal_sensor_mutex);
48 	ret = opal_sensor_read(sensor_hndl, token, &data);
49 	switch (ret) {
50 	case OPAL_ASYNC_COMPLETION:
51 		ret = opal_async_wait_response(token, &msg);
52 		if (ret) {
53 			pr_err("%s: Failed to wait for the async response, %d\n",
54 			       __func__, ret);
55 			goto out_token;
56 		}
57 
58 		ret = opal_error_code(be64_to_cpu(msg.params[1]));
59 		*sensor_data = be32_to_cpu(data);
60 		break;
61 
62 	case OPAL_SUCCESS:
63 		ret = 0;
64 		*sensor_data = be32_to_cpu(data);
65 		break;
66 
67 	default:
68 		ret = opal_error_code(ret);
69 		break;
70 	}
71 
72 out_token:
73 	mutex_unlock(&opal_sensor_mutex);
74 	opal_async_release_token(token);
75 out:
76 	return ret;
77 }
78 EXPORT_SYMBOL_GPL(opal_get_sensor_data);
79 
80 static __init int opal_sensor_init(void)
81 {
82 	struct platform_device *pdev;
83 	struct device_node *sensor;
84 
85 	sensor = of_find_node_by_path("/ibm,opal/sensors");
86 	if (!sensor) {
87 		pr_err("Opal node 'sensors' not found\n");
88 		return -ENODEV;
89 	}
90 
91 	pdev = of_platform_device_create(sensor, "opal-sensor", NULL);
92 	of_node_put(sensor);
93 
94 	return PTR_ERR_OR_ZERO(pdev);
95 }
96 machine_subsys_initcall(powernv, opal_sensor_init);
97