4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
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.
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.
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>
24 #include <linux/iio/iio.h>
26 #include <linux/mfd/ti_am335x_tscadc.h>
27 #include <linux/platform_data/ti_am335x_adc.h>
30 struct ti_tscadc_dev *mfd_tscadc;
34 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
36 return readl(adc->mfd_tscadc->tscadc_base + reg);
39 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
42 writel(val, adc->mfd_tscadc->tscadc_base + reg);
45 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
49 step_en = ((1 << adc_dev->channels) - 1);
50 step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
54 static void tiadc_step_config(struct tiadc_device *adc_dev)
56 unsigned int stepconfig;
57 int i, channels = 0, steps;
61 * There are 16 configurable steps and 8 analog input
62 * lines available which are shared between Touchscreen and ADC.
64 * Steps backwards i.e. from 16 towards 0 are used by ADC
65 * depending on number of input lines needed.
66 * Channel would represent which analog input
67 * needs to be given to ADC to digitalize data.
70 steps = TOTAL_STEPS - adc_dev->channels;
71 channels = TOTAL_CHANNELS - adc_dev->channels;
73 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
75 for (i = (steps + 1); i <= TOTAL_STEPS; i++) {
76 tiadc_writel(adc_dev, REG_STEPCONFIG(i),
77 stepconfig | STEPCONFIG_INP(channels));
78 tiadc_writel(adc_dev, REG_STEPDELAY(i),
82 step_en = get_adc_step_mask(adc_dev);
83 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
86 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
88 struct iio_chan_spec *chan_array;
91 indio_dev->num_channels = channels;
92 chan_array = kcalloc(indio_dev->num_channels,
93 sizeof(struct iio_chan_spec), GFP_KERNEL);
95 if (chan_array == NULL)
98 for (i = 0; i < (indio_dev->num_channels); i++) {
99 struct iio_chan_spec *chan = chan_array + i;
100 chan->type = IIO_VOLTAGE;
103 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
106 indio_dev->channels = chan_array;
108 return indio_dev->num_channels;
111 static void tiadc_channels_remove(struct iio_dev *indio_dev)
113 kfree(indio_dev->channels);
116 static int tiadc_read_raw(struct iio_dev *indio_dev,
117 struct iio_chan_spec const *chan,
118 int *val, int *val2, long mask)
120 struct tiadc_device *adc_dev = iio_priv(indio_dev);
122 unsigned int fifo1count, readx1;
125 * When the sub-system is first enabled,
126 * the sequencer will always start with the
127 * lowest step (1) and continue until step (16).
128 * For ex: If we have enabled 4 ADC channels and
129 * currently use only 1 out of them, the
130 * sequencer still configures all the 4 steps,
131 * leading to 3 unwanted data.
132 * Hence we need to flush out this data.
135 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
136 for (i = 0; i < fifo1count; i++) {
137 readx1 = tiadc_readl(adc_dev, REG_FIFO1);
138 if (i == chan->channel)
139 *val = readx1 & 0xfff;
141 am335x_tsc_se_update(adc_dev->mfd_tscadc);
146 static const struct iio_info tiadc_info = {
147 .read_raw = &tiadc_read_raw,
150 static int tiadc_probe(struct platform_device *pdev)
152 struct iio_dev *indio_dev;
153 struct tiadc_device *adc_dev;
154 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
155 struct mfd_tscadc_board *pdata;
158 pdata = tscadc_dev->dev->platform_data;
159 if (!pdata || !pdata->adc_init) {
160 dev_err(&pdev->dev, "Could not find platform data\n");
164 indio_dev = iio_device_alloc(sizeof(struct tiadc_device));
165 if (indio_dev == NULL) {
166 dev_err(&pdev->dev, "failed to allocate iio device\n");
170 adc_dev = iio_priv(indio_dev);
172 adc_dev->mfd_tscadc = tscadc_dev;
173 adc_dev->channels = pdata->adc_init->adc_channels;
175 indio_dev->dev.parent = &pdev->dev;
176 indio_dev->name = dev_name(&pdev->dev);
177 indio_dev->modes = INDIO_DIRECT_MODE;
178 indio_dev->info = &tiadc_info;
180 tiadc_step_config(adc_dev);
182 err = tiadc_channel_init(indio_dev, adc_dev->channels);
184 goto err_free_device;
186 err = iio_device_register(indio_dev);
188 goto err_free_channels;
190 platform_set_drvdata(pdev, indio_dev);
195 tiadc_channels_remove(indio_dev);
197 iio_device_free(indio_dev);
202 static int tiadc_remove(struct platform_device *pdev)
204 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
205 struct tiadc_device *adc_dev = iio_priv(indio_dev);
208 iio_device_unregister(indio_dev);
209 tiadc_channels_remove(indio_dev);
211 step_en = get_adc_step_mask(adc_dev);
212 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
214 iio_device_free(indio_dev);
220 static int tiadc_suspend(struct device *dev)
222 struct iio_dev *indio_dev = dev_get_drvdata(dev);
223 struct tiadc_device *adc_dev = iio_priv(indio_dev);
224 struct ti_tscadc_dev *tscadc_dev;
227 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
228 if (!device_may_wakeup(tscadc_dev->dev)) {
229 idle = tiadc_readl(adc_dev, REG_CTRL);
230 idle &= ~(CNTRLREG_TSCSSENB);
231 tiadc_writel(adc_dev, REG_CTRL, (idle |
232 CNTRLREG_POWERDOWN));
238 static int tiadc_resume(struct device *dev)
240 struct iio_dev *indio_dev = dev_get_drvdata(dev);
241 struct tiadc_device *adc_dev = iio_priv(indio_dev);
242 unsigned int restore;
244 /* Make sure ADC is powered up */
245 restore = tiadc_readl(adc_dev, REG_CTRL);
246 restore &= ~(CNTRLREG_POWERDOWN);
247 tiadc_writel(adc_dev, REG_CTRL, restore);
249 tiadc_step_config(adc_dev);
254 static const struct dev_pm_ops tiadc_pm_ops = {
255 .suspend = tiadc_suspend,
256 .resume = tiadc_resume,
258 #define TIADC_PM_OPS (&tiadc_pm_ops)
260 #define TIADC_PM_OPS NULL
263 static struct platform_driver tiadc_driver = {
266 .owner = THIS_MODULE,
269 .probe = tiadc_probe,
270 .remove = tiadc_remove,
273 module_platform_driver(tiadc_driver);
275 MODULE_DESCRIPTION("TI ADC controller driver");
276 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
277 MODULE_LICENSE("GPL");