1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * wm831x-auxadc.c -- AUXADC for Wolfson WM831x PMICs
4 *
5 * Copyright 2009-2011 Wolfson Microelectronics PLC.
6 *
7 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/delay.h>
13 #include <linux/mfd/core.h>
14 #include <linux/slab.h>
15 #include <linux/list.h>
16
17 #include <linux/mfd/wm831x/core.h>
18 #include <linux/mfd/wm831x/pdata.h>
19 #include <linux/mfd/wm831x/irq.h>
20 #include <linux/mfd/wm831x/auxadc.h>
21 #include <linux/mfd/wm831x/otp.h>
22 #include <linux/mfd/wm831x/regulator.h>
23
24 struct wm831x_auxadc_req {
25 struct list_head list;
26 enum wm831x_auxadc input;
27 int val;
28 struct completion done;
29 };
30
wm831x_auxadc_read_irq(struct wm831x * wm831x,enum wm831x_auxadc input)31 static int wm831x_auxadc_read_irq(struct wm831x *wm831x,
32 enum wm831x_auxadc input)
33 {
34 struct wm831x_auxadc_req *req;
35 int ret;
36 bool ena = false;
37
38 req = kzalloc(sizeof(*req), GFP_KERNEL);
39 if (!req)
40 return -ENOMEM;
41
42 init_completion(&req->done);
43 req->input = input;
44 req->val = -ETIMEDOUT;
45
46 mutex_lock(&wm831x->auxadc_lock);
47
48 /* Enqueue the request */
49 list_add(&req->list, &wm831x->auxadc_pending);
50
51 ena = !wm831x->auxadc_active;
52
53 if (ena) {
54 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
55 WM831X_AUX_ENA, WM831X_AUX_ENA);
56 if (ret != 0) {
57 dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n",
58 ret);
59 goto out;
60 }
61 }
62
63 /* Enable the conversion if not already running */
64 if (!(wm831x->auxadc_active & (1 << input))) {
65 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
66 1 << input, 1 << input);
67 if (ret != 0) {
68 dev_err(wm831x->dev,
69 "Failed to set AUXADC source: %d\n", ret);
70 goto out;
71 }
72
73 wm831x->auxadc_active |= 1 << input;
74 }
75
76 /* We convert at the fastest rate possible */
77 if (ena) {
78 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
79 WM831X_AUX_CVT_ENA |
80 WM831X_AUX_RATE_MASK,
81 WM831X_AUX_CVT_ENA |
82 WM831X_AUX_RATE_MASK);
83 if (ret != 0) {
84 dev_err(wm831x->dev, "Failed to start AUXADC: %d\n",
85 ret);
86 goto out;
87 }
88 }
89
90 mutex_unlock(&wm831x->auxadc_lock);
91
92 /* Wait for an interrupt */
93 wait_for_completion_timeout(&req->done, msecs_to_jiffies(500));
94
95 mutex_lock(&wm831x->auxadc_lock);
96
97 list_del(&req->list);
98 ret = req->val;
99
100 out:
101 mutex_unlock(&wm831x->auxadc_lock);
102
103 kfree(req);
104
105 return ret;
106 }
107
wm831x_auxadc_irq(int irq,void * irq_data)108 static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data)
109 {
110 struct wm831x *wm831x = irq_data;
111 struct wm831x_auxadc_req *req;
112 int ret, input, val;
113
114 ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
115 if (ret < 0) {
116 dev_err(wm831x->dev,
117 "Failed to read AUXADC data: %d\n", ret);
118 return IRQ_NONE;
119 }
120
121 input = ((ret & WM831X_AUX_DATA_SRC_MASK)
122 >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
123
124 if (input == 14)
125 input = WM831X_AUX_CAL;
126
127 val = ret & WM831X_AUX_DATA_MASK;
128
129 mutex_lock(&wm831x->auxadc_lock);
130
131 /* Disable this conversion, we're about to complete all users */
132 wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
133 1 << input, 0);
134 wm831x->auxadc_active &= ~(1 << input);
135
136 /* Turn off the entire convertor if idle */
137 if (!wm831x->auxadc_active)
138 wm831x_reg_write(wm831x, WM831X_AUXADC_CONTROL, 0);
139
140 /* Wake up any threads waiting for this request */
141 list_for_each_entry(req, &wm831x->auxadc_pending, list) {
142 if (req->input == input) {
143 req->val = val;
144 complete(&req->done);
145 }
146 }
147
148 mutex_unlock(&wm831x->auxadc_lock);
149
150 return IRQ_HANDLED;
151 }
152
wm831x_auxadc_read_polled(struct wm831x * wm831x,enum wm831x_auxadc input)153 static int wm831x_auxadc_read_polled(struct wm831x *wm831x,
154 enum wm831x_auxadc input)
155 {
156 int ret, src, timeout;
157
158 mutex_lock(&wm831x->auxadc_lock);
159
160 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
161 WM831X_AUX_ENA, WM831X_AUX_ENA);
162 if (ret < 0) {
163 dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n", ret);
164 goto out;
165 }
166
167 /* We force a single source at present */
168 src = input;
169 ret = wm831x_reg_write(wm831x, WM831X_AUXADC_SOURCE,
170 1 << src);
171 if (ret < 0) {
172 dev_err(wm831x->dev, "Failed to set AUXADC source: %d\n", ret);
173 goto out;
174 }
175
176 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
177 WM831X_AUX_CVT_ENA, WM831X_AUX_CVT_ENA);
178 if (ret < 0) {
179 dev_err(wm831x->dev, "Failed to start AUXADC: %d\n", ret);
180 goto disable;
181 }
182
183 /* If we're not using interrupts then poll the
184 * interrupt status register */
185 timeout = 5;
186 while (timeout) {
187 msleep(1);
188
189 ret = wm831x_reg_read(wm831x,
190 WM831X_INTERRUPT_STATUS_1);
191 if (ret < 0) {
192 dev_err(wm831x->dev,
193 "ISR 1 read failed: %d\n", ret);
194 goto disable;
195 }
196
197 /* Did it complete? */
198 if (ret & WM831X_AUXADC_DATA_EINT) {
199 wm831x_reg_write(wm831x,
200 WM831X_INTERRUPT_STATUS_1,
201 WM831X_AUXADC_DATA_EINT);
202 break;
203 } else {
204 dev_err(wm831x->dev,
205 "AUXADC conversion timeout\n");
206 ret = -EBUSY;
207 goto disable;
208 }
209 }
210
211 ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
212 if (ret < 0) {
213 dev_err(wm831x->dev,
214 "Failed to read AUXADC data: %d\n", ret);
215 goto disable;
216 }
217
218 src = ((ret & WM831X_AUX_DATA_SRC_MASK)
219 >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
220
221 if (src == 14)
222 src = WM831X_AUX_CAL;
223
224 if (src != input) {
225 dev_err(wm831x->dev, "Data from source %d not %d\n",
226 src, input);
227 ret = -EINVAL;
228 } else {
229 ret &= WM831X_AUX_DATA_MASK;
230 }
231
232 disable:
233 wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0);
234 out:
235 mutex_unlock(&wm831x->auxadc_lock);
236 return ret;
237 }
238
239 /**
240 * wm831x_auxadc_read: Read a value from the WM831x AUXADC
241 *
242 * @wm831x: Device to read from.
243 * @input: AUXADC input to read.
244 */
wm831x_auxadc_read(struct wm831x * wm831x,enum wm831x_auxadc input)245 int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
246 {
247 return wm831x->auxadc_read(wm831x, input);
248 }
249 EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
250
251 /**
252 * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
253 *
254 * @wm831x: Device to read from.
255 * @input: AUXADC input to read.
256 */
wm831x_auxadc_read_uv(struct wm831x * wm831x,enum wm831x_auxadc input)257 int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
258 {
259 int ret;
260
261 ret = wm831x_auxadc_read(wm831x, input);
262 if (ret < 0)
263 return ret;
264
265 ret *= 1465;
266
267 return ret;
268 }
269 EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);
270
wm831x_auxadc_init(struct wm831x * wm831x)271 void wm831x_auxadc_init(struct wm831x *wm831x)
272 {
273 int ret;
274
275 mutex_init(&wm831x->auxadc_lock);
276 INIT_LIST_HEAD(&wm831x->auxadc_pending);
277
278 if (wm831x->irq) {
279 wm831x->auxadc_read = wm831x_auxadc_read_irq;
280
281 ret = request_threaded_irq(wm831x_irq(wm831x,
282 WM831X_IRQ_AUXADC_DATA),
283 NULL, wm831x_auxadc_irq,
284 IRQF_ONESHOT,
285 "auxadc", wm831x);
286 if (ret < 0) {
287 dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
288 ret);
289 wm831x->auxadc_read = NULL;
290 }
291 }
292
293 if (!wm831x->auxadc_read)
294 wm831x->auxadc_read = wm831x_auxadc_read_polled;
295 }
296
