wm831x_backup.c

  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
 19struct wm831x_backup {
 20	struct wm831x *wm831x;
 21	struct power_supply *backup;
 22	struct power_supply_desc backup_desc;
 23	char name[20];
 24};
 25
 26static 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
 43static 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
112static 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
152static 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
162static int wm831x_backup_probe(struct platform_device *pdev)
163{
164	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
165	struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
166	struct wm831x_backup *devdata;
167
168	devdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_backup),
169				GFP_KERNEL);
170	if (devdata == NULL)
171		return -ENOMEM;
172
173	devdata->wm831x = wm831x;
174
175	/* We ignore configuration failures since we can still read
176	 * back the status without enabling the charger (which may
177	 * already be enabled anyway).
178	 */
179	wm831x_config_backup(wm831x);
180
181	if (wm831x_pdata && wm831x_pdata->wm831x_num)
182		snprintf(devdata->name, sizeof(devdata->name),
183			 "wm831x-backup.%d", wm831x_pdata->wm831x_num);
184	else
185		snprintf(devdata->name, sizeof(devdata->name),
186			 "wm831x-backup");
187
188	devdata->backup_desc.name = devdata->name;
189	devdata->backup_desc.type = POWER_SUPPLY_TYPE_BATTERY;
190	devdata->backup_desc.properties = wm831x_backup_props;
191	devdata->backup_desc.num_properties = ARRAY_SIZE(wm831x_backup_props);
192	devdata->backup_desc.get_property = wm831x_backup_get_prop;
193	devdata->backup = devm_power_supply_register(&pdev->dev,
194						     &devdata->backup_desc, NULL);
195
196	return PTR_ERR_OR_ZERO(devdata->backup);
197}
198
199static struct platform_driver wm831x_backup_driver = {
200	.probe = wm831x_backup_probe,
201	.driver = {
202		.name = "wm831x-backup",
203	},
204};
205
206module_platform_driver(wm831x_backup_driver);
207
208MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
209MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
210MODULE_LICENSE("GPL");
211MODULE_ALIAS("platform:wm831x-backup");