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
wm831x_backup_read_voltage(struct wm831x * wm831x,enum wm831x_auxadc src,union power_supply_propval * val)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
wm831x_config_backup(struct wm831x * wm831x)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
wm831x_backup_get_prop(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)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
wm831x_backup_probe(struct platform_device * pdev)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
wm831x_backup_remove(struct platform_device * pdev)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 module_platform_driver(wm831x_backup_driver);
230
231 MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
232 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
233 MODULE_LICENSE("GPL");
234 MODULE_ALIAS("platform:wm831x-backup");
235