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
24struct wm831x_auxadc_req {
25 struct list_head list;
26 enum wm831x_auxadc input;
27 int val;
28 struct completion done;
29};
30
31static 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(size: sizeof(*req), GFP_KERNEL);
39 if (!req)
40 return -ENOMEM;
41
42 init_completion(x: &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(new: &req->list, head: &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 mask: 1 << input, val: 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(lock: &wm831x->auxadc_lock);
91
92 /* Wait for an interrupt */
93 wait_for_completion_timeout(x: &req->done, timeout: msecs_to_jiffies(m: 500));
94
95 mutex_lock(&wm831x->auxadc_lock);
96 ret = req->val;
97
98out:
99 list_del(entry: &req->list);
100 mutex_unlock(lock: &wm831x->auxadc_lock);
101
102 kfree(objp: req);
103
104 return ret;
105}
106
107static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data)
108{
109 struct wm831x *wm831x = irq_data;
110 struct wm831x_auxadc_req *req;
111 int ret, input, val;
112
113 ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
114 if (ret < 0) {
115 dev_err(wm831x->dev,
116 "Failed to read AUXADC data: %d\n", ret);
117 return IRQ_NONE;
118 }
119
120 input = ((ret & WM831X_AUX_DATA_SRC_MASK)
121 >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
122
123 if (input == 14)
124 input = WM831X_AUX_CAL;
125
126 val = ret & WM831X_AUX_DATA_MASK;
127
128 mutex_lock(&wm831x->auxadc_lock);
129
130 /* Disable this conversion, we're about to complete all users */
131 wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
132 mask: 1 << input, val: 0);
133 wm831x->auxadc_active &= ~(1 << input);
134
135 /* Turn off the entire convertor if idle */
136 if (!wm831x->auxadc_active)
137 wm831x_reg_write(wm831x, WM831X_AUXADC_CONTROL, val: 0);
138
139 /* Wake up any threads waiting for this request */
140 list_for_each_entry(req, &wm831x->auxadc_pending, list) {
141 if (req->input == input) {
142 req->val = val;
143 complete(&req->done);
144 }
145 }
146
147 mutex_unlock(lock: &wm831x->auxadc_lock);
148
149 return IRQ_HANDLED;
150}
151
152static int wm831x_auxadc_read_polled(struct wm831x *wm831x,
153 enum wm831x_auxadc input)
154{
155 int ret, src;
156
157 mutex_lock(&wm831x->auxadc_lock);
158
159 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
160 WM831X_AUX_ENA, WM831X_AUX_ENA);
161 if (ret < 0) {
162 dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n", ret);
163 goto out;
164 }
165
166 /* We force a single source at present */
167 src = input;
168 ret = wm831x_reg_write(wm831x, WM831X_AUXADC_SOURCE,
169 val: 1 << src);
170 if (ret < 0) {
171 dev_err(wm831x->dev, "Failed to set AUXADC source: %d\n", ret);
172 goto out;
173 }
174
175 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
176 WM831X_AUX_CVT_ENA, WM831X_AUX_CVT_ENA);
177 if (ret < 0) {
178 dev_err(wm831x->dev, "Failed to start AUXADC: %d\n", ret);
179 goto disable;
180 }
181
182 /* If we're not using interrupts then read the interrupt status register */
183 msleep(msecs: 20);
184
185 ret = wm831x_reg_read(wm831x, WM831X_INTERRUPT_STATUS_1);
186 if (ret < 0) {
187 dev_err(wm831x->dev,
188 "ISR 1 read failed: %d\n", ret);
189 goto disable;
190 }
191
192 /* Did it complete? */
193 if (ret & WM831X_AUXADC_DATA_EINT) {
194 wm831x_reg_write(wm831x, WM831X_INTERRUPT_STATUS_1,
195 WM831X_AUXADC_DATA_EINT);
196 } else {
197 dev_err(wm831x->dev,
198 "AUXADC conversion timeout\n");
199 ret = -EBUSY;
200 goto disable;
201 }
202
203 ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
204 if (ret < 0) {
205 dev_err(wm831x->dev,
206 "Failed to read AUXADC data: %d\n", ret);
207 goto disable;
208 }
209
210 src = ((ret & WM831X_AUX_DATA_SRC_MASK)
211 >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
212
213 if (src == 14)
214 src = WM831X_AUX_CAL;
215
216 if (src != input) {
217 dev_err(wm831x->dev, "Data from source %d not %d\n",
218 src, input);
219 ret = -EINVAL;
220 } else {
221 ret &= WM831X_AUX_DATA_MASK;
222 }
223
224disable:
225 wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, val: 0);
226out:
227 mutex_unlock(lock: &wm831x->auxadc_lock);
228 return ret;
229}
230
231/**
232 * wm831x_auxadc_read: Read a value from the WM831x AUXADC
233 *
234 * @wm831x: Device to read from.
235 * @input: AUXADC input to read.
236 */
237int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
238{
239 return wm831x->auxadc_read(wm831x, input);
240}
241EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
242
243/**
244 * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
245 *
246 * @wm831x: Device to read from.
247 * @input: AUXADC input to read.
248 */
249int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
250{
251 int ret;
252
253 ret = wm831x_auxadc_read(wm831x, input);
254 if (ret < 0)
255 return ret;
256
257 ret *= 1465;
258
259 return ret;
260}
261EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);
262
263void wm831x_auxadc_init(struct wm831x *wm831x)
264{
265 int ret;
266
267 mutex_init(&wm831x->auxadc_lock);
268 INIT_LIST_HEAD(list: &wm831x->auxadc_pending);
269
270 if (wm831x->irq) {
271 wm831x->auxadc_read = wm831x_auxadc_read_irq;
272
273 ret = request_threaded_irq(irq: wm831x_irq(wm831x,
274 WM831X_IRQ_AUXADC_DATA),
275 NULL, thread_fn: wm831x_auxadc_irq,
276 IRQF_ONESHOT,
277 name: "auxadc", dev: wm831x);
278 if (ret < 0) {
279 dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
280 ret);
281 wm831x->auxadc_read = NULL;
282 }
283 }
284
285 if (!wm831x->auxadc_read)
286 wm831x->auxadc_read = wm831x_auxadc_read_polled;
287}
288

source code of linux/drivers/mfd/wm831x-auxadc.c