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