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(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	ret = req->val;
97
98out:
99	list_del(&req->list);
100	mutex_unlock(&wm831x->auxadc_lock);
101
102	kfree(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			1 << input, 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, 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(&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, timeout;
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			       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 poll the
183	 * interrupt status register */
184	timeout = 5;
185	while (timeout) {
186		msleep(1);
187
188		ret = wm831x_reg_read(wm831x,
189				      WM831X_INTERRUPT_STATUS_1);
190		if (ret < 0) {
191			dev_err(wm831x->dev,
192				"ISR 1 read failed: %d\n", ret);
193			goto disable;
194		}
195
196		/* Did it complete? */
197		if (ret & WM831X_AUXADC_DATA_EINT) {
198			wm831x_reg_write(wm831x,
199					 WM831X_INTERRUPT_STATUS_1,
200					 WM831X_AUXADC_DATA_EINT);
201			break;
202		} else {
203			dev_err(wm831x->dev,
204				"AUXADC conversion timeout\n");
205			ret = -EBUSY;
206			goto disable;
207		}
208	}
209
210	ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
211	if (ret < 0) {
212		dev_err(wm831x->dev,
213			"Failed to read AUXADC data: %d\n", ret);
214		goto disable;
215	}
216
217	src = ((ret & WM831X_AUX_DATA_SRC_MASK)
218	       >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
219
220	if (src == 14)
221		src = WM831X_AUX_CAL;
222
223	if (src != input) {
224		dev_err(wm831x->dev, "Data from source %d not %d\n",
225			src, input);
226		ret = -EINVAL;
227	} else {
228		ret &= WM831X_AUX_DATA_MASK;
229	}
230
231disable:
232	wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0);
233out:
234	mutex_unlock(&wm831x->auxadc_lock);
235	return ret;
236}
237
238/**
239 * wm831x_auxadc_read: Read a value from the WM831x AUXADC
240 *
241 * @wm831x: Device to read from.
242 * @input: AUXADC input to read.
243 */
244int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
245{
246	return wm831x->auxadc_read(wm831x, input);
247}
248EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
249
250/**
251 * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
252 *
253 * @wm831x: Device to read from.
254 * @input: AUXADC input to read.
255 */
256int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
257{
258	int ret;
259
260	ret = wm831x_auxadc_read(wm831x, input);
261	if (ret < 0)
262		return ret;
263
264	ret *= 1465;
265
266	return ret;
267}
268EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);
269
270void wm831x_auxadc_init(struct wm831x *wm831x)
271{
272	int ret;
273
274	mutex_init(&wm831x->auxadc_lock);
275	INIT_LIST_HEAD(&wm831x->auxadc_pending);
276
277	if (wm831x->irq) {
278		wm831x->auxadc_read = wm831x_auxadc_read_irq;
279
280		ret = request_threaded_irq(wm831x_irq(wm831x,
281						      WM831X_IRQ_AUXADC_DATA),
282					   NULL, wm831x_auxadc_irq,
283					   IRQF_ONESHOT,
284					   "auxadc", wm831x);
285		if (ret < 0) {
286			dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
287				ret);
288			wm831x->auxadc_read = NULL;
289		}
290	}
291
292	if (!wm831x->auxadc_read)
293		wm831x->auxadc_read = wm831x_auxadc_read_polled;
294}
295