Merge 4.6-rc4 into driver-core-next
[linux-2.6/btrfs-unstable.git] / drivers / mfd / pcf50633-adc.c
blobc1984b0d1b65273d64651f73e7f9c92fc0ef4e35
1 /* NXP PCF50633 ADC Driver
3 * (C) 2006-2008 by Openmoko, Inc.
4 * Author: Balaji Rao <balajirrao@openmoko.org>
5 * All rights reserved.
7 * Broken down from monstrous PCF50633 driver mainly by
8 * Harald Welte, Andy Green and Werner Almesberger
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.
15 * NOTE: This driver does not yet support subtractive ADC mode, which means
16 * you can do only one measurement per read request.
19 #include <linux/kernel.h>
20 #include <linux/slab.h>
21 #include <linux/module.h>
22 #include <linux/device.h>
23 #include <linux/platform_device.h>
24 #include <linux/completion.h>
26 #include <linux/mfd/pcf50633/core.h>
27 #include <linux/mfd/pcf50633/adc.h>
29 struct pcf50633_adc_request {
30 int mux;
31 int avg;
32 void (*callback)(struct pcf50633 *, void *, int);
33 void *callback_param;
36 struct pcf50633_adc_sync_request {
37 int result;
38 struct completion completion;
41 #define PCF50633_MAX_ADC_FIFO_DEPTH 8
43 struct pcf50633_adc {
44 struct pcf50633 *pcf;
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;
53 static inline struct pcf50633_adc *__to_adc(struct pcf50633 *pcf)
55 return platform_get_drvdata(pcf->adc_pdev);
58 static void adc_setup(struct pcf50633 *pcf, int channel, int avg)
60 channel &= PCF50633_ADCC1_ADCMUX_MASK;
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);
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);
71 static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)
73 struct pcf50633_adc *adc = __to_adc(pcf);
74 int head;
76 head = adc->queue_head;
78 if (!adc->queue[head])
79 return;
81 adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);
84 static int
85 adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req)
87 struct pcf50633_adc *adc = __to_adc(pcf);
88 int head, tail;
90 mutex_lock(&adc->queue_mutex);
92 head = adc->queue_head;
93 tail = adc->queue_tail;
95 if (adc->queue[tail]) {
96 mutex_unlock(&adc->queue_mutex);
97 dev_err(pcf->dev, "ADC queue is full, dropping request\n");
98 return -EBUSY;
101 adc->queue[tail] = req;
102 if (head == tail)
103 trigger_next_adc_job_if_any(pcf);
104 adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
106 mutex_unlock(&adc->queue_mutex);
108 return 0;
111 static void pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param,
112 int result)
114 struct pcf50633_adc_sync_request *req = param;
116 req->result = result;
117 complete(&req->completion);
120 int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
122 struct pcf50633_adc_sync_request req;
123 int ret;
125 init_completion(&req.completion);
127 ret = pcf50633_adc_async_read(pcf, mux, avg,
128 pcf50633_adc_sync_read_callback, &req);
129 if (ret)
130 return ret;
132 wait_for_completion(&req.completion);
134 return req.result;
136 EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);
138 int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
139 void (*callback)(struct pcf50633 *, void *, int),
140 void *callback_param)
142 struct pcf50633_adc_request *req;
144 /* req is freed when the result is ready, in interrupt handler */
145 req = kmalloc(sizeof(*req), GFP_KERNEL);
146 if (!req)
147 return -ENOMEM;
149 req->mux = mux;
150 req->avg = avg;
151 req->callback = callback;
152 req->callback_param = callback_param;
154 return adc_enqueue_request(pcf, req);
156 EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);
158 static int adc_result(struct pcf50633 *pcf)
160 u8 adcs1, adcs3;
161 u16 result;
163 adcs1 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS1);
164 adcs3 = pcf50633_reg_read(pcf, PCF50633_REG_ADCS3);
165 result = (adcs1 << 2) | (adcs3 & PCF50633_ADCS3_ADCDAT1L_MASK);
167 dev_dbg(pcf->dev, "adc result = %d\n", result);
169 return result;
172 static void pcf50633_adc_irq(int irq, void *data)
174 struct pcf50633_adc *adc = data;
175 struct pcf50633 *pcf = adc->pcf;
176 struct pcf50633_adc_request *req;
177 int head, res;
179 mutex_lock(&adc->queue_mutex);
180 head = adc->queue_head;
182 req = adc->queue[head];
183 if (WARN_ON(!req)) {
184 dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
185 mutex_unlock(&adc->queue_mutex);
186 return;
188 adc->queue[head] = NULL;
189 adc->queue_head = (head + 1) &
190 (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
192 res = adc_result(pcf);
193 trigger_next_adc_job_if_any(pcf);
195 mutex_unlock(&adc->queue_mutex);
197 req->callback(pcf, req->callback_param, res);
198 kfree(req);
201 static int pcf50633_adc_probe(struct platform_device *pdev)
203 struct pcf50633_adc *adc;
205 adc = devm_kzalloc(&pdev->dev, sizeof(*adc), GFP_KERNEL);
206 if (!adc)
207 return -ENOMEM;
209 adc->pcf = dev_to_pcf50633(pdev->dev.parent);
210 platform_set_drvdata(pdev, adc);
212 pcf50633_register_irq(adc->pcf, PCF50633_IRQ_ADCRDY,
213 pcf50633_adc_irq, adc);
215 mutex_init(&adc->queue_mutex);
217 return 0;
220 static int pcf50633_adc_remove(struct platform_device *pdev)
222 struct pcf50633_adc *adc = platform_get_drvdata(pdev);
223 int i, head;
225 pcf50633_free_irq(adc->pcf, PCF50633_IRQ_ADCRDY);
227 mutex_lock(&adc->queue_mutex);
228 head = adc->queue_head;
230 if (WARN_ON(adc->queue[head]))
231 dev_err(adc->pcf->dev,
232 "adc driver removed with request pending\n");
234 for (i = 0; i < PCF50633_MAX_ADC_FIFO_DEPTH; i++)
235 kfree(adc->queue[i]);
237 mutex_unlock(&adc->queue_mutex);
239 return 0;
242 static struct platform_driver pcf50633_adc_driver = {
243 .driver = {
244 .name = "pcf50633-adc",
246 .probe = pcf50633_adc_probe,
247 .remove = pcf50633_adc_remove,
250 module_platform_driver(pcf50633_adc_driver);
252 MODULE_AUTHOR("Balaji Rao <balajirrao@openmoko.org>");
253 MODULE_DESCRIPTION("PCF50633 adc driver");
254 MODULE_LICENSE("GPL");
255 MODULE_ALIAS("platform:pcf50633-adc");