Root/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
22struct wm831x_backup {
23    struct wm831x *wm831x;
24    struct power_supply backup;
25    char name[20];
26};
27
28static 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
45static 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
114static 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
154static 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
164static __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
205err_kmalloc:
206    kfree(devdata);
207    return ret;
208}
209
210static __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
221static 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
229module_platform_driver(wm831x_backup_driver);
230
231MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
232MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
233MODULE_LICENSE("GPL");
234MODULE_ALIAS("platform:wm831x-backup");
235

Archive Download this file



interactive