arch/powerpc/platforms/powernv/opal-sensor.c

   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(opal_get_async_rc(msg));
  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 int __init 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 }