Merge branch 'mfd/wm8994' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie...
[linux-2.6.git] / drivers / power / wm831x_backup.c
1 /*
2  * Backup battery driver for Wolfson Microelectronics wm831x PMICs
3  *
4  * Copyright 2009 Wolfson Microelectronics PLC.
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 version 2 as
8  * published by the Free Software Foundation.
9  */
10
11 #include <linux/module.h>
12 #include <linux/err.h>
13 #include <linux/platform_device.h>
14 #include <linux/power_supply.h>
15 #include <linux/slab.h>
16
17 #include <linux/mfd/wm831x/core.h>
18 #include <linux/mfd/wm831x/auxadc.h>
19 #include <linux/mfd/wm831x/pmu.h>
20 #include <linux/mfd/wm831x/pdata.h>
21
22 struct wm831x_backup {
23         struct wm831x *wm831x;
24         struct power_supply backup;
25         char name[20];
26 };
27
28 static int wm831x_backup_read_voltage(struct wm831x *wm831x,
29                                      enum wm831x_auxadc src,
30                                      union power_supply_propval *val)
31 {
32         int ret;
33
34         ret = wm831x_auxadc_read_uv(wm831x, src);
35         if (ret >= 0)
36                 val->intval = ret;
37
38         return ret;
39 }
40
41 /*********************************************************************
42  *              Backup supply properties
43  *********************************************************************/
44
45 static void wm831x_config_backup(struct wm831x *wm831x)
46 {
47         struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
48         struct wm831x_backup_pdata *pdata;
49         int ret, reg;
50
51         if (!wm831x_pdata || !wm831x_pdata->backup) {
52                 dev_warn(wm831x->dev,
53                          "No backup battery charger configuration\n");
54                 return;
55         }
56
57         pdata = wm831x_pdata->backup;
58
59         reg = 0;
60
61         if (pdata->charger_enable)
62                 reg |= WM831X_BKUP_CHG_ENA | WM831X_BKUP_BATT_DET_ENA;
63         if (pdata->no_constant_voltage)
64                 reg |= WM831X_BKUP_CHG_MODE;
65
66         switch (pdata->vlim) {
67         case 2500:
68                 break;
69         case 3100:
70                 reg |= WM831X_BKUP_CHG_VLIM;
71                 break;
72         default:
73                 dev_err(wm831x->dev, "Invalid backup voltage limit %dmV\n",
74                         pdata->vlim);
75         }
76
77         switch (pdata->ilim) {
78         case 100:
79                 break;
80         case 200:
81                 reg |= 1;
82                 break;
83         case 300:
84                 reg |= 2;
85                 break;
86         case 400:
87                 reg |= 3;
88                 break;
89         default:
90                 dev_err(wm831x->dev, "Invalid backup current limit %duA\n",
91                         pdata->ilim);
92         }
93
94         ret = wm831x_reg_unlock(wm831x);
95         if (ret != 0) {
96                 dev_err(wm831x->dev, "Failed to unlock registers: %d\n", ret);
97                 return;
98         }
99
100         ret = wm831x_set_bits(wm831x, WM831X_BACKUP_CHARGER_CONTROL,
101                               WM831X_BKUP_CHG_ENA_MASK |
102                               WM831X_BKUP_CHG_MODE_MASK |
103                               WM831X_BKUP_BATT_DET_ENA_MASK |
104                               WM831X_BKUP_CHG_VLIM_MASK |
105                               WM831X_BKUP_CHG_ILIM_MASK,
106                               reg);
107         if (ret != 0)
108                 dev_err(wm831x->dev,
109                         "Failed to set backup charger config: %d\n", ret);
110
111         wm831x_reg_lock(wm831x);
112 }
113
114 static int wm831x_backup_get_prop(struct power_supply *psy,
115                                   enum power_supply_property psp,
116                                   union power_supply_propval *val)
117 {
118         struct wm831x_backup *devdata = dev_get_drvdata(psy->dev->parent);
119         struct wm831x *wm831x = devdata->wm831x;
120         int ret = 0;
121
122         ret = wm831x_reg_read(wm831x, WM831X_BACKUP_CHARGER_CONTROL);
123         if (ret < 0)
124                 return ret;
125
126         switch (psp) {
127         case POWER_SUPPLY_PROP_STATUS:
128                 if (ret & WM831X_BKUP_CHG_STS)
129                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
130                 else
131                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
132                 break;
133
134         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
135                 ret = wm831x_backup_read_voltage(wm831x, WM831X_AUX_BKUP_BATT,
136                                                 val);
137                 break;
138
139         case POWER_SUPPLY_PROP_PRESENT:
140                 if (ret & WM831X_BKUP_CHG_STS)
141                         val->intval = 1;
142                 else
143                         val->intval = 0;
144                 break;
145
146         default:
147                 ret = -EINVAL;
148                 break;
149         }
150
151         return ret;
152 }
153
154 static enum power_supply_property wm831x_backup_props[] = {
155         POWER_SUPPLY_PROP_STATUS,
156         POWER_SUPPLY_PROP_VOLTAGE_NOW,
157         POWER_SUPPLY_PROP_PRESENT,
158 };
159
160 /*********************************************************************
161  *              Initialisation
162  *********************************************************************/
163
164 static __devinit int wm831x_backup_probe(struct platform_device *pdev)
165 {
166         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
167         struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
168         struct wm831x_backup *devdata;
169         struct power_supply *backup;
170         int ret;
171
172         devdata = kzalloc(sizeof(struct wm831x_backup), GFP_KERNEL);
173         if (devdata == NULL)
174                 return -ENOMEM;
175
176         devdata->wm831x = wm831x;
177         platform_set_drvdata(pdev, devdata);
178
179         backup = &devdata->backup;
180
181         /* We ignore configuration failures since we can still read
182          * back the status without enabling the charger (which may
183          * already be enabled anyway).
184          */
185         wm831x_config_backup(wm831x);
186
187         if (wm831x_pdata && wm831x_pdata->wm831x_num)
188                 snprintf(devdata->name, sizeof(devdata->name),
189                          "wm831x-backup.%d", wm831x_pdata->wm831x_num);
190         else
191                 snprintf(devdata->name, sizeof(devdata->name),
192                          "wm831x-backup");
193
194         backup->name = devdata->name;
195         backup->type = POWER_SUPPLY_TYPE_BATTERY;
196         backup->properties = wm831x_backup_props;
197         backup->num_properties = ARRAY_SIZE(wm831x_backup_props);
198         backup->get_property = wm831x_backup_get_prop;
199         ret = power_supply_register(&pdev->dev, backup);
200         if (ret)
201                 goto err_kmalloc;
202
203         return ret;
204
205 err_kmalloc:
206         kfree(devdata);
207         return ret;
208 }
209
210 static __devexit int wm831x_backup_remove(struct platform_device *pdev)
211 {
212         struct wm831x_backup *devdata = platform_get_drvdata(pdev);
213
214         power_supply_unregister(&devdata->backup);
215         kfree(devdata->backup.name);
216         kfree(devdata);
217
218         return 0;
219 }
220
221 static struct platform_driver wm831x_backup_driver = {
222         .probe = wm831x_backup_probe,
223         .remove = __devexit_p(wm831x_backup_remove),
224         .driver = {
225                 .name = "wm831x-backup",
226         },
227 };
228
229 static int __init wm831x_backup_init(void)
230 {
231         return platform_driver_register(&wm831x_backup_driver);
232 }
233 module_init(wm831x_backup_init);
234
235 static void __exit wm831x_backup_exit(void)
236 {
237         platform_driver_unregister(&wm831x_backup_driver);
238 }
239 module_exit(wm831x_backup_exit);
240
241 MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
242 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
243 MODULE_LICENSE("GPL");
244 MODULE_ALIAS("platform:wm831x-backup");