1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Backup battery driver for Wolfson Microelectronics wm831x PMICs |
4 | * |
5 | * Copyright 2009 Wolfson Microelectronics PLC. |
6 | */ |
7 | |
8 | #include <linux/module.h> |
9 | #include <linux/err.h> |
10 | #include <linux/platform_device.h> |
11 | #include <linux/power_supply.h> |
12 | #include <linux/slab.h> |
13 | |
14 | #include <linux/mfd/wm831x/core.h> |
15 | #include <linux/mfd/wm831x/auxadc.h> |
16 | #include <linux/mfd/wm831x/pmu.h> |
17 | #include <linux/mfd/wm831x/pdata.h> |
18 | |
19 | struct wm831x_backup { |
20 | struct wm831x *wm831x; |
21 | struct power_supply *backup; |
22 | struct power_supply_desc backup_desc; |
23 | char name[20]; |
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, input: 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 | val: 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(dev: 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, src: 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 int wm831x_backup_probe(struct platform_device *pdev) |
163 | { |
164 | struct wm831x *wm831x = dev_get_drvdata(dev: pdev->dev.parent); |
165 | struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data; |
166 | struct wm831x_backup *devdata; |
167 | |
168 | devdata = devm_kzalloc(dev: &pdev->dev, size: sizeof(struct wm831x_backup), |
169 | GFP_KERNEL); |
170 | if (devdata == NULL) |
171 | return -ENOMEM; |
172 | |
173 | devdata->wm831x = wm831x; |
174 | platform_set_drvdata(pdev, data: devdata); |
175 | |
176 | /* We ignore configuration failures since we can still read |
177 | * back the status without enabling the charger (which may |
178 | * already be enabled anyway). |
179 | */ |
180 | wm831x_config_backup(wm831x); |
181 | |
182 | if (wm831x_pdata && wm831x_pdata->wm831x_num) |
183 | snprintf(buf: devdata->name, size: sizeof(devdata->name), |
184 | fmt: "wm831x-backup.%d" , wm831x_pdata->wm831x_num); |
185 | else |
186 | snprintf(buf: devdata->name, size: sizeof(devdata->name), |
187 | fmt: "wm831x-backup" ); |
188 | |
189 | devdata->backup_desc.name = devdata->name; |
190 | devdata->backup_desc.type = POWER_SUPPLY_TYPE_BATTERY; |
191 | devdata->backup_desc.properties = wm831x_backup_props; |
192 | devdata->backup_desc.num_properties = ARRAY_SIZE(wm831x_backup_props); |
193 | devdata->backup_desc.get_property = wm831x_backup_get_prop; |
194 | devdata->backup = power_supply_register(parent: &pdev->dev, |
195 | desc: &devdata->backup_desc, NULL); |
196 | |
197 | return PTR_ERR_OR_ZERO(ptr: devdata->backup); |
198 | } |
199 | |
200 | static void wm831x_backup_remove(struct platform_device *pdev) |
201 | { |
202 | struct wm831x_backup *devdata = platform_get_drvdata(pdev); |
203 | |
204 | power_supply_unregister(psy: devdata->backup); |
205 | } |
206 | |
207 | static struct platform_driver wm831x_backup_driver = { |
208 | .probe = wm831x_backup_probe, |
209 | .remove_new = wm831x_backup_remove, |
210 | .driver = { |
211 | .name = "wm831x-backup" , |
212 | }, |
213 | }; |
214 | |
215 | module_platform_driver(wm831x_backup_driver); |
216 | |
217 | MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs" ); |
218 | MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>" ); |
219 | MODULE_LICENSE("GPL" ); |
220 | MODULE_ALIAS("platform:wm831x-backup" ); |
221 | |