iio: ti_am335x_adc: optimize memory usage
[linux-2.6-block.git] / drivers / iio / adc / ti_am335x_adc.c
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1/*
2 * TI ADC MFD driver
3 *
4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation version 2.
9 *
10 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
11 * kind, whether express or implied; without even the implied warranty
12 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/err.h>
19#include <linux/module.h>
20#include <linux/slab.h>
21#include <linux/interrupt.h>
22#include <linux/platform_device.h>
23#include <linux/io.h>
24#include <linux/iio/iio.h>
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25#include <linux/of.h>
26#include <linux/of_device.h>
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27#include <linux/iio/machine.h>
28#include <linux/iio/driver.h>
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29
30#include <linux/mfd/ti_am335x_tscadc.h>
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31
32struct tiadc_device {
33 struct ti_tscadc_dev *mfd_tscadc;
34 int channels;
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35 u8 channel_line[8];
36 u8 channel_step[8];
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37};
38
39static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
40{
41 return readl(adc->mfd_tscadc->tscadc_base + reg);
42}
43
44static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
45 unsigned int val)
46{
47 writel(val, adc->mfd_tscadc->tscadc_base + reg);
48}
49
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50static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
51{
52 u32 step_en;
53
54 step_en = ((1 << adc_dev->channels) - 1);
55 step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
56 return step_en;
57}
58
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59static void tiadc_step_config(struct tiadc_device *adc_dev)
60{
61 unsigned int stepconfig;
18926ede 62 int i, steps;
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63
64 /*
65 * There are 16 configurable steps and 8 analog input
66 * lines available which are shared between Touchscreen and ADC.
67 *
68 * Steps backwards i.e. from 16 towards 0 are used by ADC
69 * depending on number of input lines needed.
70 * Channel would represent which analog input
71 * needs to be given to ADC to digitalize data.
72 */
73
74 steps = TOTAL_STEPS - adc_dev->channels;
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75 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
76
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77 for (i = 0; i < adc_dev->channels; i++) {
78 int chan;
79
80 chan = adc_dev->channel_line[i];
81 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
82 stepconfig | STEPCONFIG_INP(chan));
83 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
5e53a69b 84 STEPCONFIG_OPENDLY);
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85 adc_dev->channel_step[i] = steps;
86 steps++;
5e53a69b 87 }
b1451e54 88
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89}
90
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91static const char * const chan_name_ain[] = {
92 "AIN0",
93 "AIN1",
94 "AIN2",
95 "AIN3",
96 "AIN4",
97 "AIN5",
98 "AIN6",
99 "AIN7",
100};
101
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102static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
103{
c80df483 104 struct tiadc_device *adc_dev = iio_priv(indio_dev);
5e53a69b 105 struct iio_chan_spec *chan_array;
c80df483 106 struct iio_chan_spec *chan;
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107 int i;
108
109 indio_dev->num_channels = channels;
c80df483 110 chan_array = kcalloc(channels,
5e53a69b 111 sizeof(struct iio_chan_spec), GFP_KERNEL);
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112 if (chan_array == NULL)
113 return -ENOMEM;
114
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115 chan = chan_array;
116 for (i = 0; i < channels; i++, chan++) {
117
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118 chan->type = IIO_VOLTAGE;
119 chan->indexed = 1;
18926ede 120 chan->channel = adc_dev->channel_line[i];
6c572522 121 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
18926ede 122 chan->datasheet_name = chan_name_ain[chan->channel];
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123 chan->scan_type.sign = 'u';
124 chan->scan_type.realbits = 12;
0f6fc7d5 125 chan->scan_type.storagebits = 16;
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126 }
127
128 indio_dev->channels = chan_array;
129
c80df483 130 return 0;
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131}
132
133static void tiadc_channels_remove(struct iio_dev *indio_dev)
134{
135 kfree(indio_dev->channels);
136}
137
138static int tiadc_read_raw(struct iio_dev *indio_dev,
139 struct iio_chan_spec const *chan,
140 int *val, int *val2, long mask)
141{
142 struct tiadc_device *adc_dev = iio_priv(indio_dev);
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143 int i, map_val;
144 unsigned int fifo1count, read, stepid;
18926ede 145 u32 step = UINT_MAX;
1460c152 146 bool found = false;
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147 u32 step_en;
148 unsigned long timeout = jiffies + usecs_to_jiffies
149 (IDLE_TIMEOUT * adc_dev->channels);
150 step_en = get_adc_step_mask(adc_dev);
151 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
152
153 /* Wait for ADC sequencer to complete sampling */
154 while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
155 if (time_after(jiffies, timeout))
156 return -EAGAIN;
157 }
158 map_val = chan->channel + TOTAL_CHANNELS;
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159
160 /*
161 * When the sub-system is first enabled,
162 * the sequencer will always start with the
163 * lowest step (1) and continue until step (16).
164 * For ex: If we have enabled 4 ADC channels and
165 * currently use only 1 out of them, the
166 * sequencer still configures all the 4 steps,
167 * leading to 3 unwanted data.
168 * Hence we need to flush out this data.
169 */
170
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171 for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
172 if (chan->channel == adc_dev->channel_line[i]) {
173 step = adc_dev->channel_step[i];
174 break;
175 }
176 }
177 if (WARN_ON_ONCE(step == UINT_MAX))
178 return -EINVAL;
179
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180 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
181 for (i = 0; i < fifo1count; i++) {
18926ede 182 read = tiadc_readl(adc_dev, REG_FIFO1);
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183 stepid = read & FIFOREAD_CHNLID_MASK;
184 stepid = stepid >> 0x10;
185
186 if (stepid == map_val) {
187 read = read & FIFOREAD_DATA_MASK;
1460c152 188 found = true;
0f6fc7d5 189 *val = (u16) read;
1460c152 190 }
5e53a69b 191 }
b1451e54 192
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193 if (found == false)
194 return -EBUSY;
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195 return IIO_VAL_INT;
196}
197
198static const struct iio_info tiadc_info = {
199 .read_raw = &tiadc_read_raw,
bc93aa76 200 .driver_module = THIS_MODULE,
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201};
202
fc52692c 203static int tiadc_probe(struct platform_device *pdev)
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204{
205 struct iio_dev *indio_dev;
206 struct tiadc_device *adc_dev;
6f39ac4e 207 struct device_node *node = pdev->dev.of_node;
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208 struct property *prop;
209 const __be32 *cur;
5e53a69b 210 int err;
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211 u32 val;
212 int channels = 0;
5e53a69b 213
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214 if (!node) {
215 dev_err(&pdev->dev, "Could not find valid DT data.\n");
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216 return -EINVAL;
217 }
218
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219 indio_dev = devm_iio_device_alloc(&pdev->dev,
220 sizeof(struct tiadc_device));
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221 if (indio_dev == NULL) {
222 dev_err(&pdev->dev, "failed to allocate iio device\n");
a0648130 223 return -ENOMEM;
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224 }
225 adc_dev = iio_priv(indio_dev);
226
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227 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
228
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229 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
230 adc_dev->channel_line[channels] = val;
231 channels++;
232 }
233 adc_dev->channels = channels;
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234
235 indio_dev->dev.parent = &pdev->dev;
236 indio_dev->name = dev_name(&pdev->dev);
237 indio_dev->modes = INDIO_DIRECT_MODE;
238 indio_dev->info = &tiadc_info;
239
240 tiadc_step_config(adc_dev);
241
242 err = tiadc_channel_init(indio_dev, adc_dev->channels);
243 if (err < 0)
a0648130 244 return err;
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245
246 err = iio_device_register(indio_dev);
247 if (err)
248 goto err_free_channels;
249
250 platform_set_drvdata(pdev, indio_dev);
251
252 return 0;
253
254err_free_channels:
255 tiadc_channels_remove(indio_dev);
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256 return err;
257}
258
fc52692c 259static int tiadc_remove(struct platform_device *pdev)
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260{
261 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
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262 struct tiadc_device *adc_dev = iio_priv(indio_dev);
263 u32 step_en;
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264
265 iio_device_unregister(indio_dev);
266 tiadc_channels_remove(indio_dev);
267
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268 step_en = get_adc_step_mask(adc_dev);
269 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
270
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271 return 0;
272}
273
274#ifdef CONFIG_PM
275static int tiadc_suspend(struct device *dev)
276{
277 struct iio_dev *indio_dev = dev_get_drvdata(dev);
278 struct tiadc_device *adc_dev = iio_priv(indio_dev);
a9bce1b0 279 struct ti_tscadc_dev *tscadc_dev;
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280 unsigned int idle;
281
a9bce1b0 282 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
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283 if (!device_may_wakeup(tscadc_dev->dev)) {
284 idle = tiadc_readl(adc_dev, REG_CTRL);
285 idle &= ~(CNTRLREG_TSCSSENB);
286 tiadc_writel(adc_dev, REG_CTRL, (idle |
287 CNTRLREG_POWERDOWN));
288 }
289
290 return 0;
291}
292
293static int tiadc_resume(struct device *dev)
294{
295 struct iio_dev *indio_dev = dev_get_drvdata(dev);
296 struct tiadc_device *adc_dev = iio_priv(indio_dev);
297 unsigned int restore;
298
299 /* Make sure ADC is powered up */
300 restore = tiadc_readl(adc_dev, REG_CTRL);
301 restore &= ~(CNTRLREG_POWERDOWN);
302 tiadc_writel(adc_dev, REG_CTRL, restore);
303
304 tiadc_step_config(adc_dev);
305
306 return 0;
307}
308
309static const struct dev_pm_ops tiadc_pm_ops = {
310 .suspend = tiadc_suspend,
311 .resume = tiadc_resume,
312};
313#define TIADC_PM_OPS (&tiadc_pm_ops)
314#else
315#define TIADC_PM_OPS NULL
316#endif
317
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318static const struct of_device_id ti_adc_dt_ids[] = {
319 { .compatible = "ti,am3359-adc", },
320 { }
321};
322MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
323
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324static struct platform_driver tiadc_driver = {
325 .driver = {
9f99928f 326 .name = "TI-am335x-adc",
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327 .owner = THIS_MODULE,
328 .pm = TIADC_PM_OPS,
6f39ac4e 329 .of_match_table = of_match_ptr(ti_adc_dt_ids),
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330 },
331 .probe = tiadc_probe,
fc52692c 332 .remove = tiadc_remove,
5e53a69b 333};
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334module_platform_driver(tiadc_driver);
335
336MODULE_DESCRIPTION("TI ADC controller driver");
337MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
338MODULE_LICENSE("GPL");