1 /*
2  * wm831x-isink.c  --  Current sink driver for the WM831x series
3  *
4  * Copyright 2009 Wolfson Microelectronics PLC.
5  *
6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7  *
8  *  This program is free software; you can redistribute  it and/or modify it
9  *  under  the terms of  the GNU General  Public License as published by the
10  *  Free Software Foundation;  either version 2 of the  License, or (at your
11  *  option) any later version.
12  */
13 
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/init.h>
17 #include <linux/bitops.h>
18 #include <linux/err.h>
19 #include <linux/i2c.h>
20 #include <linux/platform_device.h>
21 #include <linux/regulator/driver.h>
22 #include <linux/slab.h>
23 
24 #include <linux/mfd/wm831x/core.h>
25 #include <linux/mfd/wm831x/regulator.h>
26 #include <linux/mfd/wm831x/pdata.h>
27 
28 #define WM831X_ISINK_MAX_NAME 7
29 
30 struct wm831x_isink {
31 	char name[WM831X_ISINK_MAX_NAME];
32 	struct regulator_desc desc;
33 	int reg;
34 	struct wm831x *wm831x;
35 	struct regulator_dev *regulator;
36 };
37 
38 static int wm831x_isink_enable(struct regulator_dev *rdev)
39 {
40 	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
41 	struct wm831x *wm831x = isink->wm831x;
42 	int ret;
43 
44 	/* We have a two stage enable: first start the ISINK... */
45 	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA,
46 			      WM831X_CS1_ENA);
47 	if (ret != 0)
48 		return ret;
49 
50 	/* ...then enable drive */
51 	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_DRIVE,
52 			      WM831X_CS1_DRIVE);
53 	if (ret != 0)
54 		wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA, 0);
55 
56 	return ret;
57 
58 }
59 
60 static int wm831x_isink_disable(struct regulator_dev *rdev)
61 {
62 	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
63 	struct wm831x *wm831x = isink->wm831x;
64 	int ret;
65 
66 	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_DRIVE, 0);
67 	if (ret < 0)
68 		return ret;
69 
70 	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA, 0);
71 	if (ret < 0)
72 		return ret;
73 
74 	return ret;
75 
76 }
77 
78 static int wm831x_isink_is_enabled(struct regulator_dev *rdev)
79 {
80 	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
81 	struct wm831x *wm831x = isink->wm831x;
82 	int ret;
83 
84 	ret = wm831x_reg_read(wm831x, isink->reg);
85 	if (ret < 0)
86 		return ret;
87 
88 	if ((ret & (WM831X_CS1_ENA | WM831X_CS1_DRIVE)) ==
89 	    (WM831X_CS1_ENA | WM831X_CS1_DRIVE))
90 		return 1;
91 	else
92 		return 0;
93 }
94 
95 static int wm831x_isink_set_current(struct regulator_dev *rdev,
96 				    int min_uA, int max_uA)
97 {
98 	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
99 	struct wm831x *wm831x = isink->wm831x;
100 	int ret, i;
101 
102 	for (i = 0; i < ARRAY_SIZE(wm831x_isinkv_values); i++) {
103 		int val = wm831x_isinkv_values[i];
104 		if (min_uA <= val && val <= max_uA) {
105 			ret = wm831x_set_bits(wm831x, isink->reg,
106 					      WM831X_CS1_ISEL_MASK, i);
107 			return ret;
108 		}
109 	}
110 
111 	return -EINVAL;
112 }
113 
114 static int wm831x_isink_get_current(struct regulator_dev *rdev)
115 {
116 	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
117 	struct wm831x *wm831x = isink->wm831x;
118 	int ret;
119 
120 	ret = wm831x_reg_read(wm831x, isink->reg);
121 	if (ret < 0)
122 		return ret;
123 
124 	ret &= WM831X_CS1_ISEL_MASK;
125 	if (ret > WM831X_ISINK_MAX_ISEL)
126 		ret = WM831X_ISINK_MAX_ISEL;
127 
128 	return wm831x_isinkv_values[ret];
129 }
130 
131 static const struct regulator_ops wm831x_isink_ops = {
132 	.is_enabled = wm831x_isink_is_enabled,
133 	.enable = wm831x_isink_enable,
134 	.disable = wm831x_isink_disable,
135 	.set_current_limit = wm831x_isink_set_current,
136 	.get_current_limit = wm831x_isink_get_current,
137 };
138 
139 static irqreturn_t wm831x_isink_irq(int irq, void *data)
140 {
141 	struct wm831x_isink *isink = data;
142 
143 	regulator_notifier_call_chain(isink->regulator,
144 				      REGULATOR_EVENT_OVER_CURRENT,
145 				      NULL);
146 
147 	return IRQ_HANDLED;
148 }
149 
150 
151 static int wm831x_isink_probe(struct platform_device *pdev)
152 {
153 	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
154 	struct wm831x_pdata *pdata = dev_get_platdata(wm831x->dev);
155 	struct wm831x_isink *isink;
156 	int id = pdev->id % ARRAY_SIZE(pdata->isink);
157 	struct regulator_config config = { };
158 	struct resource *res;
159 	int ret, irq;
160 
161 	dev_dbg(&pdev->dev, "Probing ISINK%d\n", id + 1);
162 
163 	if (pdata == NULL || pdata->isink[id] == NULL)
164 		return -ENODEV;
165 
166 	isink = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_isink),
167 			     GFP_KERNEL);
168 	if (!isink)
169 		return -ENOMEM;
170 
171 	isink->wm831x = wm831x;
172 
173 	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
174 	if (res == NULL) {
175 		dev_err(&pdev->dev, "No REG resource\n");
176 		ret = -EINVAL;
177 		goto err;
178 	}
179 	isink->reg = res->start;
180 
181 	/* For current parts this is correct; probably need to revisit
182 	 * in future.
183 	 */
184 	snprintf(isink->name, sizeof(isink->name), "ISINK%d", id + 1);
185 	isink->desc.name = isink->name;
186 	isink->desc.id = id;
187 	isink->desc.ops = &wm831x_isink_ops;
188 	isink->desc.type = REGULATOR_CURRENT;
189 	isink->desc.owner = THIS_MODULE;
190 
191 	config.dev = pdev->dev.parent;
192 	config.init_data = pdata->isink[id];
193 	config.driver_data = isink;
194 
195 	isink->regulator = devm_regulator_register(&pdev->dev, &isink->desc,
196 						   &config);
197 	if (IS_ERR(isink->regulator)) {
198 		ret = PTR_ERR(isink->regulator);
199 		dev_err(wm831x->dev, "Failed to register ISINK%d: %d\n",
200 			id + 1, ret);
201 		goto err;
202 	}
203 
204 	irq = wm831x_irq(wm831x, platform_get_irq(pdev, 0));
205 	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
206 					wm831x_isink_irq,
207 					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
208 					isink->name,
209 					isink);
210 	if (ret != 0) {
211 		dev_err(&pdev->dev, "Failed to request ISINK IRQ %d: %d\n",
212 			irq, ret);
213 		goto err;
214 	}
215 
216 	platform_set_drvdata(pdev, isink);
217 
218 	return 0;
219 
220 err:
221 	return ret;
222 }
223 
224 static struct platform_driver wm831x_isink_driver = {
225 	.probe = wm831x_isink_probe,
226 	.driver		= {
227 		.name	= "wm831x-isink",
228 	},
229 };
230 
231 static int __init wm831x_isink_init(void)
232 {
233 	int ret;
234 	ret = platform_driver_register(&wm831x_isink_driver);
235 	if (ret != 0)
236 		pr_err("Failed to register WM831x ISINK driver: %d\n", ret);
237 
238 	return ret;
239 }
240 subsys_initcall(wm831x_isink_init);
241 
242 static void __exit wm831x_isink_exit(void)
243 {
244 	platform_driver_unregister(&wm831x_isink_driver);
245 }
246 module_exit(wm831x_isink_exit);
247 
248 /* Module information */
249 MODULE_AUTHOR("Mark Brown");
250 MODULE_DESCRIPTION("WM831x current sink driver");
251 MODULE_LICENSE("GPL");
252 MODULE_ALIAS("platform:wm831x-isink");
253