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/of_device.h>
27 #include <linux/iio/machine.h>
28 #include <linux/iio/driver.h>
30 #include <linux/mfd/ti_am335x_tscadc.h>
33 struct ti_tscadc_dev *mfd_tscadc;
39 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
41 return readl(adc->mfd_tscadc->tscadc_base + reg);
44 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
47 writel(val, adc->mfd_tscadc->tscadc_base + reg);
50 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
54 step_en = ((1 << adc_dev->channels) - 1);
55 step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
59 static void tiadc_step_config(struct tiadc_device *adc_dev)
61 unsigned int stepconfig;
66 * There are 16 configurable steps and 8 analog input
67 * lines available which are shared between Touchscreen and ADC.
69 * Steps backwards i.e. from 16 towards 0 are used by ADC
70 * depending on number of input lines needed.
71 * Channel would represent which analog input
72 * needs to be given to ADC to digitalize data.
75 steps = TOTAL_STEPS - adc_dev->channels;
76 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
78 for (i = 0; i < adc_dev->channels; i++) {
81 chan = adc_dev->channel_line[i];
82 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
83 stepconfig | STEPCONFIG_INP(chan));
84 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
86 adc_dev->channel_step[i] = steps;
89 step_en = get_adc_step_mask(adc_dev);
90 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
93 static const char * const chan_name_ain[] = {
104 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
106 struct tiadc_device *adc_dev = iio_priv(indio_dev);
107 struct iio_chan_spec *chan_array;
108 struct iio_chan_spec *chan;
111 indio_dev->num_channels = channels;
112 chan_array = kcalloc(channels,
113 sizeof(struct iio_chan_spec), GFP_KERNEL);
114 if (chan_array == NULL)
118 for (i = 0; i < channels; i++, chan++) {
120 chan->type = IIO_VOLTAGE;
122 chan->channel = adc_dev->channel_line[i];
123 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
124 chan->datasheet_name = chan_name_ain[chan->channel];
125 chan->scan_type.sign = 'u';
126 chan->scan_type.realbits = 12;
127 chan->scan_type.storagebits = 32;
130 indio_dev->channels = chan_array;
135 static void tiadc_channels_remove(struct iio_dev *indio_dev)
137 kfree(indio_dev->channels);
140 static int tiadc_read_raw(struct iio_dev *indio_dev,
141 struct iio_chan_spec const *chan,
142 int *val, int *val2, long mask)
144 struct tiadc_device *adc_dev = iio_priv(indio_dev);
146 unsigned int fifo1count, read;
151 * When the sub-system is first enabled,
152 * the sequencer will always start with the
153 * lowest step (1) and continue until step (16).
154 * For ex: If we have enabled 4 ADC channels and
155 * currently use only 1 out of them, the
156 * sequencer still configures all the 4 steps,
157 * leading to 3 unwanted data.
158 * Hence we need to flush out this data.
161 for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
162 if (chan->channel == adc_dev->channel_line[i]) {
163 step = adc_dev->channel_step[i];
167 if (WARN_ON_ONCE(step == UINT_MAX))
170 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
171 for (i = 0; i < fifo1count; i++) {
172 read = tiadc_readl(adc_dev, REG_FIFO1);
173 if (read >> 16 == step) {
178 am335x_tsc_se_update(adc_dev->mfd_tscadc);
184 static const struct iio_info tiadc_info = {
185 .read_raw = &tiadc_read_raw,
186 .driver_module = THIS_MODULE,
189 static int tiadc_probe(struct platform_device *pdev)
191 struct iio_dev *indio_dev;
192 struct tiadc_device *adc_dev;
193 struct device_node *node = pdev->dev.of_node;
194 struct property *prop;
201 dev_err(&pdev->dev, "Could not find valid DT data.\n");
205 indio_dev = iio_device_alloc(sizeof(struct tiadc_device));
206 if (indio_dev == NULL) {
207 dev_err(&pdev->dev, "failed to allocate iio device\n");
211 adc_dev = iio_priv(indio_dev);
213 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
215 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
216 adc_dev->channel_line[channels] = val;
219 adc_dev->channels = channels;
221 indio_dev->dev.parent = &pdev->dev;
222 indio_dev->name = dev_name(&pdev->dev);
223 indio_dev->modes = INDIO_DIRECT_MODE;
224 indio_dev->info = &tiadc_info;
226 tiadc_step_config(adc_dev);
228 err = tiadc_channel_init(indio_dev, adc_dev->channels);
230 goto err_free_device;
232 err = iio_device_register(indio_dev);
234 goto err_free_channels;
236 platform_set_drvdata(pdev, indio_dev);
241 tiadc_channels_remove(indio_dev);
243 iio_device_free(indio_dev);
248 static int tiadc_remove(struct platform_device *pdev)
250 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
251 struct tiadc_device *adc_dev = iio_priv(indio_dev);
254 iio_device_unregister(indio_dev);
255 tiadc_channels_remove(indio_dev);
257 step_en = get_adc_step_mask(adc_dev);
258 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
260 iio_device_free(indio_dev);
266 static int tiadc_suspend(struct device *dev)
268 struct iio_dev *indio_dev = dev_get_drvdata(dev);
269 struct tiadc_device *adc_dev = iio_priv(indio_dev);
270 struct ti_tscadc_dev *tscadc_dev;
273 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
274 if (!device_may_wakeup(tscadc_dev->dev)) {
275 idle = tiadc_readl(adc_dev, REG_CTRL);
276 idle &= ~(CNTRLREG_TSCSSENB);
277 tiadc_writel(adc_dev, REG_CTRL, (idle |
278 CNTRLREG_POWERDOWN));
284 static int tiadc_resume(struct device *dev)
286 struct iio_dev *indio_dev = dev_get_drvdata(dev);
287 struct tiadc_device *adc_dev = iio_priv(indio_dev);
288 unsigned int restore;
290 /* Make sure ADC is powered up */
291 restore = tiadc_readl(adc_dev, REG_CTRL);
292 restore &= ~(CNTRLREG_POWERDOWN);
293 tiadc_writel(adc_dev, REG_CTRL, restore);
295 tiadc_step_config(adc_dev);
300 static const struct dev_pm_ops tiadc_pm_ops = {
301 .suspend = tiadc_suspend,
302 .resume = tiadc_resume,
304 #define TIADC_PM_OPS (&tiadc_pm_ops)
306 #define TIADC_PM_OPS NULL
309 static const struct of_device_id ti_adc_dt_ids[] = {
310 { .compatible = "ti,am3359-adc", },
313 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
315 static struct platform_driver tiadc_driver = {
317 .name = "TI-am335x-adc",
318 .owner = THIS_MODULE,
320 .of_match_table = of_match_ptr(ti_adc_dt_ids),
322 .probe = tiadc_probe,
323 .remove = tiadc_remove,
325 module_platform_driver(tiadc_driver);
327 MODULE_DESCRIPTION("TI ADC controller driver");
328 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
329 MODULE_LICENSE("GPL");