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Patil, Rachna5e53a692012-10-16 12:55:45 +05301/*
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>
25
26#include <linux/mfd/ti_am335x_tscadc.h>
27#include <linux/platform_data/ti_am335x_adc.h>
28
29struct tiadc_device {
30 struct ti_tscadc_dev *mfd_tscadc;
31 int channels;
32};
33
34static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
35{
36 return readl(adc->mfd_tscadc->tscadc_base + reg);
37}
38
39static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
40 unsigned int val)
41{
42 writel(val, adc->mfd_tscadc->tscadc_base + reg);
43}
44
45static void tiadc_step_config(struct tiadc_device *adc_dev)
46{
47 unsigned int stepconfig;
48 int i, channels = 0, steps;
49
50 /*
51 * There are 16 configurable steps and 8 analog input
52 * lines available which are shared between Touchscreen and ADC.
53 *
54 * Steps backwards i.e. from 16 towards 0 are used by ADC
55 * depending on number of input lines needed.
56 * Channel would represent which analog input
57 * needs to be given to ADC to digitalize data.
58 */
59
60 steps = TOTAL_STEPS - adc_dev->channels;
61 channels = TOTAL_CHANNELS - adc_dev->channels;
62
63 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
64
65 for (i = (steps + 1); i <= TOTAL_STEPS; i++) {
66 tiadc_writel(adc_dev, REG_STEPCONFIG(i),
67 stepconfig | STEPCONFIG_INP(channels));
68 tiadc_writel(adc_dev, REG_STEPDELAY(i),
69 STEPCONFIG_OPENDLY);
70 channels++;
71 }
72 tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
73}
74
75static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
76{
77 struct iio_chan_spec *chan_array;
78 int i;
79
80 indio_dev->num_channels = channels;
81 chan_array = kcalloc(indio_dev->num_channels,
82 sizeof(struct iio_chan_spec), GFP_KERNEL);
83
84 if (chan_array == NULL)
85 return -ENOMEM;
86
87 for (i = 0; i < (indio_dev->num_channels); i++) {
88 struct iio_chan_spec *chan = chan_array + i;
89 chan->type = IIO_VOLTAGE;
90 chan->indexed = 1;
91 chan->channel = i;
Jonathan Cameron6c572522013-02-27 19:07:18 +000092 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
Patil, Rachna5e53a692012-10-16 12:55:45 +053093 }
94
95 indio_dev->channels = chan_array;
96
97 return indio_dev->num_channels;
98}
99
100static void tiadc_channels_remove(struct iio_dev *indio_dev)
101{
102 kfree(indio_dev->channels);
103}
104
105static int tiadc_read_raw(struct iio_dev *indio_dev,
106 struct iio_chan_spec const *chan,
107 int *val, int *val2, long mask)
108{
109 struct tiadc_device *adc_dev = iio_priv(indio_dev);
110 int i;
111 unsigned int fifo1count, readx1;
112
113 /*
114 * When the sub-system is first enabled,
115 * the sequencer will always start with the
116 * lowest step (1) and continue until step (16).
117 * For ex: If we have enabled 4 ADC channels and
118 * currently use only 1 out of them, the
119 * sequencer still configures all the 4 steps,
120 * leading to 3 unwanted data.
121 * Hence we need to flush out this data.
122 */
123
124 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
125 for (i = 0; i < fifo1count; i++) {
126 readx1 = tiadc_readl(adc_dev, REG_FIFO1);
127 if (i == chan->channel)
128 *val = readx1 & 0xfff;
129 }
130 tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
131
132 return IIO_VAL_INT;
133}
134
135static const struct iio_info tiadc_info = {
136 .read_raw = &tiadc_read_raw,
Wei Yongjunbc93aa72013-07-06 05:20:00 +0100137 .driver_module = THIS_MODULE,
Patil, Rachna5e53a692012-10-16 12:55:45 +0530138};
139
Greg Kroah-Hartmanfc526922012-12-21 13:21:43 -0800140static int tiadc_probe(struct platform_device *pdev)
Patil, Rachna5e53a692012-10-16 12:55:45 +0530141{
142 struct iio_dev *indio_dev;
143 struct tiadc_device *adc_dev;
144 struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
145 struct mfd_tscadc_board *pdata;
146 int err;
147
148 pdata = tscadc_dev->dev->platform_data;
149 if (!pdata || !pdata->adc_init) {
150 dev_err(&pdev->dev, "Could not find platform data\n");
151 return -EINVAL;
152 }
153
154 indio_dev = iio_device_alloc(sizeof(struct tiadc_device));
155 if (indio_dev == NULL) {
156 dev_err(&pdev->dev, "failed to allocate iio device\n");
157 err = -ENOMEM;
158 goto err_ret;
159 }
160 adc_dev = iio_priv(indio_dev);
161
162 adc_dev->mfd_tscadc = tscadc_dev;
163 adc_dev->channels = pdata->adc_init->adc_channels;
164
165 indio_dev->dev.parent = &pdev->dev;
166 indio_dev->name = dev_name(&pdev->dev);
167 indio_dev->modes = INDIO_DIRECT_MODE;
168 indio_dev->info = &tiadc_info;
169
170 tiadc_step_config(adc_dev);
171
172 err = tiadc_channel_init(indio_dev, adc_dev->channels);
173 if (err < 0)
174 goto err_free_device;
175
176 err = iio_device_register(indio_dev);
177 if (err)
178 goto err_free_channels;
179
180 platform_set_drvdata(pdev, indio_dev);
181
182 return 0;
183
184err_free_channels:
185 tiadc_channels_remove(indio_dev);
186err_free_device:
187 iio_device_free(indio_dev);
188err_ret:
189 return err;
190}
191
Greg Kroah-Hartmanfc526922012-12-21 13:21:43 -0800192static int tiadc_remove(struct platform_device *pdev)
Patil, Rachna5e53a692012-10-16 12:55:45 +0530193{
194 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
195
196 iio_device_unregister(indio_dev);
197 tiadc_channels_remove(indio_dev);
198
199 iio_device_free(indio_dev);
200
201 return 0;
202}
203
204#ifdef CONFIG_PM
205static int tiadc_suspend(struct device *dev)
206{
207 struct iio_dev *indio_dev = dev_get_drvdata(dev);
208 struct tiadc_device *adc_dev = iio_priv(indio_dev);
209 struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
210 unsigned int idle;
211
212 if (!device_may_wakeup(tscadc_dev->dev)) {
213 idle = tiadc_readl(adc_dev, REG_CTRL);
214 idle &= ~(CNTRLREG_TSCSSENB);
215 tiadc_writel(adc_dev, REG_CTRL, (idle |
216 CNTRLREG_POWERDOWN));
217 }
218
219 return 0;
220}
221
222static int tiadc_resume(struct device *dev)
223{
224 struct iio_dev *indio_dev = dev_get_drvdata(dev);
225 struct tiadc_device *adc_dev = iio_priv(indio_dev);
226 unsigned int restore;
227
228 /* Make sure ADC is powered up */
229 restore = tiadc_readl(adc_dev, REG_CTRL);
230 restore &= ~(CNTRLREG_POWERDOWN);
231 tiadc_writel(adc_dev, REG_CTRL, restore);
232
233 tiadc_step_config(adc_dev);
234
235 return 0;
236}
237
238static const struct dev_pm_ops tiadc_pm_ops = {
239 .suspend = tiadc_suspend,
240 .resume = tiadc_resume,
241};
242#define TIADC_PM_OPS (&tiadc_pm_ops)
243#else
244#define TIADC_PM_OPS NULL
245#endif
246
247static struct platform_driver tiadc_driver = {
248 .driver = {
249 .name = "tiadc",
250 .owner = THIS_MODULE,
251 .pm = TIADC_PM_OPS,
252 },
253 .probe = tiadc_probe,
Greg Kroah-Hartmanfc526922012-12-21 13:21:43 -0800254 .remove = tiadc_remove,
Patil, Rachna5e53a692012-10-16 12:55:45 +0530255};
256
257module_platform_driver(tiadc_driver);
258
259MODULE_DESCRIPTION("TI ADC controller driver");
260MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
261MODULE_LICENSE("GPL");