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authorBalaji Rao <balajirrao@openmoko.org>2009-01-08 19:49:26 -0500
committerSamuel Ortiz <samuel@sortiz.org>2009-01-10 19:34:23 -0500
commit08c3e06a5eb27d43b712adef18379f8464425e71 (patch)
tree63950d3beac51f8ca4e51c4fae7959a50608f31e /drivers/mfd/pcf50633-adc.c
parentf52046b14b1e1a8a02ae48d0c69d39c5e204644f (diff)
mfd: PCF50633 adc driver
This patch adds basic support for the PCF50633 ADC. The subtractive mode is not supported yet. Since we don't have adc subsystem, it currently lives in drivers/mfd. Signed-off-by: Balaji Rao <balajirrao@openmoko.org> Cc: Andy Green <andy@openmoko.com> Acked-by: Jonathan Cameron <jonathan.cameron@gmail.com> Signed-off-by: Samuel Ortiz <sameo@openedhand.com>
Diffstat (limited to 'drivers/mfd/pcf50633-adc.c')
-rw-r--r--drivers/mfd/pcf50633-adc.c277
1 files changed, 277 insertions, 0 deletions
diff --git a/drivers/mfd/pcf50633-adc.c b/drivers/mfd/pcf50633-adc.c
new file mode 100644
index 000000000000..c2d05becfa97
--- /dev/null
+++ b/drivers/mfd/pcf50633-adc.c
@@ -0,0 +1,277 @@
1/* NXP PCF50633 ADC Driver
2 *
3 * (C) 2006-2008 by Openmoko, Inc.
4 * Author: Balaji Rao <balajirrao@openmoko.org>
5 * All rights reserved.
6 *
7 * Broken down from monstrous PCF50633 driver mainly by
8 * Harald Welte, Andy Green and Werner Almesberger
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 *
15 * NOTE: This driver does not yet support subtractive ADC mode, which means
16 * you can do only one measurement per read request.
17 */
18
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/init.h>
22#include <linux/device.h>
23#include <linux/platform_device.h>
24#include <linux/completion.h>
25
26#include <linux/mfd/pcf50633/core.h>
27#include <linux/mfd/pcf50633/adc.h>
28
29struct pcf50633_adc_request {
30 int mux;
31 int avg;
32 int result;
33 void (*callback)(struct pcf50633 *, void *, int);
34 void *callback_param;
35
36 /* Used in case of sync requests */
37 struct completion completion;
38
39};
40
41#define PCF50633_MAX_ADC_FIFO_DEPTH 8
42
43struct pcf50633_adc {
44 struct pcf50633 *pcf;
45
46 /* Private stuff */
47 struct pcf50633_adc_request *queue[PCF50633_MAX_ADC_FIFO_DEPTH];
48 int queue_head;
49 int queue_tail;
50 struct mutex queue_mutex;
51};
52
53static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf)
54{
55 return platform_get_drvdata(pcf->adc_pdev);
56}
57
58static void adc_setup(struct pcf50633 *pcf, int channel, int avg)
59{
60 channel &= PCF50633_ADCC1_ADCMUX_MASK;
61
62 /* kill ratiometric, but enable ACCSW biasing */
63 pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00);
64 pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01);
65
66 /* start ADC conversion on selected channel */
67 pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg |
68 PCF50633_ADCC1_ADCSTART | PCF50633_ADCC1_RES_10BIT);
69}
70
71static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)
72{
73 struct pcf50633_adc *adc = __to_adc(pcf);
74 int head;
75
76 mutex_lock(&adc->queue_mutex);
77
78 head = adc->queue_head;
79
80 if (!adc->queue[head]) {
81 mutex_unlock(&adc->queue_mutex);
82 return;
83 }
84 mutex_unlock(&adc->queue_mutex);
85
86 adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);
87}
88
89static int
90adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req)
91{
92 struct pcf50633_adc *adc = __to_adc(pcf);
93 int head, tail;
94
95 mutex_lock(&adc->queue_mutex);
96
97 head = adc->queue_head;
98 tail = adc->queue_tail;
99
100 if (adc->queue[tail]) {
101 mutex_unlock(&adc->queue_mutex);
102 return -EBUSY;
103 }
104
105 adc->queue[tail] = req;
106 adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
107
108 mutex_unlock(&adc->queue_mutex);
109
110 trigger_next_adc_job_if_any(pcf);
111
112 return 0;
113}
114
115static void
116pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result)
117{
118 struct pcf50633_adc_request *req = param;
119
120 req->result = result;
121 complete(&req->completion);
122}
123
124int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
125{
126 struct pcf50633_adc_request *req;
127
128 /* req is freed when the result is ready, in interrupt handler */
129 req = kzalloc(sizeof(*req), GFP_KERNEL);
130 if (!req)
131 return -ENOMEM;
132
133 req->mux = mux;
134 req->avg = avg;
135 req->callback = pcf50633_adc_sync_read_callback;
136 req->callback_param = req;
137
138 init_completion(&req->completion);
139 adc_enqueue_request(pcf, req);
140 wait_for_completion(&req->completion);
141
142 return req->result;
143}
144EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);
145
146int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
147 void (*callback)(struct pcf50633 *, void *, int),
148 void *callback_param)
149{
150 struct pcf50633_adc_request *req;
151
152 /* req is freed when the result is ready, in interrupt handler */
153 req = kmalloc(sizeof(*req), GFP_KERNEL);
154 if (!req)
155 return -ENOMEM;
156
157 req->mux = mux;
158 req->avg = avg;
159 req->callback = callback;
160 req->callback_param = callback_param;
161
162 adc_enqueue_request(pcf, req);
163
164 return 0;
165}
166EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);
167
168static int adc_result(struct pcf50633 *pcf)
169{
170 u8 adcs1, adcs3;
171 u16 result;
172
173 adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);
174 adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);
175 result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);
176
177 dev_dbg(pcf->dev, "adc result = %d\n", result);
178
179 return result;
180}
181
182static void pcf50633_adc_irq(int irq, void *data)
183{
184 struct pcf50633_adc *adc = data;
185 struct pcf50633 *pcf = adc->pcf;
186 struct pcf50633_adc_request *req;
187 int head;
188
189 mutex_lock(&adc->queue_mutex);
190 head = adc->queue_head;
191
192 req = adc->queue[head];
193 if (WARN_ON(!req)) {
194 dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
195 mutex_unlock(&adc->queue_mutex);
196 return;
197 }
198 adc->queue[head] = NULL;
199 adc->queue_head = (head + 1) &
200 (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
201
202 mutex_unlock(&adc->queue_mutex);
203
204 req->callback(pcf, req->callback_param, adc_result(pcf));
205 kfree(req);
206
207 trigger_next_adc_job_if_any(pcf);
208}
209
210static int __devinit pcf50633_adc_probe(struct platform_device *pdev)
211{
212 struct pcf50633_subdev_pdata *pdata = pdev->dev.platform_data;
213 struct pcf50633_adc *adc;
214
215 adc = kzalloc(sizeof(*adc), GFP_KERNEL);
216 if (!adc)
217 return -ENOMEM;
218
219 adc->pcf = pdata->pcf;
220 platform_set_drvdata(pdev, adc);
221
222 pcf50633_register_irq(pdata->pcf, PCF50633_IRQ_ADCRDY,
223 pcf50633_adc_irq, adc);
224
225 mutex_init(&adc->queue_mutex);
226
227 return 0;
228}
229
230static int __devexit pcf50633_adc_remove(struct platform_device *pdev)
231{
232 struct pcf50633_adc *adc = platform_get_drvdata(pdev);
233 int i, head;
234
235 pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);
236
237 mutex_lock(&adc->queue_mutex);
238 head = adc->queue_head;
239
240 if (WARN_ON(adc->queue[head]))
241 dev_err(adc->pcf->dev,
242 "adc driver removed with request pending\n");
243
244 for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)
245 kfree(adc->queue[i]);
246
247 mutex_unlock(&adc->queue_mutex);
248 kfree(adc);
249
250 return 0;
251}
252
253static struct platform_driver pcf50633_adc_driver = {
254 .driver = {
255 .name = "pcf50633-adc",
256 },
257 .probe = pcf50633_adc_probe,
258 .remove = __devexit_p(pcf50633_adc_remove),
259};
260
261static int __init pcf50633_adc_init(void)
262{
263 return platform_driver_register(&pcf50633_adc_driver);
264}
265module_init(pcf50633_adc_init);
266
267static void __exit pcf50633_adc_exit(void)
268{
269 platform_driver_unregister(&pcf50633_adc_driver);
270}
271module_exit(pcf50633_adc_exit);
272
273MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");
274MODULE_DESCRIPTION("PCF50633 adc driver");
275MODULE_LICENSE("GPL");
276MODULE_ALIAS("platform:pcf50633-adc");
277