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;
65 * There are 16 configurable steps and 8 analog input
66 * lines available which are shared between Touchscreen and ADC.
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.
74 steps = TOTAL_STEPS - adc_dev->channels;
75 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
77 for (i = 0; i < adc_dev->channels; i++) {
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),
85 adc_dev->channel_step[i] = steps;
91 static const char * const chan_name_ain[] = {
102 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
104 struct tiadc_device *adc_dev = iio_priv(indio_dev);
105 struct iio_chan_spec *chan_array;
106 struct iio_chan_spec *chan;
109 indio_dev->num_channels = channels;
110 chan_array = kcalloc(channels,
111 sizeof(struct iio_chan_spec), GFP_KERNEL);
112 if (chan_array == NULL)
116 for (i = 0; i < channels; i++, chan++) {
118 chan->type = IIO_VOLTAGE;
120 chan->channel = adc_dev->channel_line[i];
121 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
122 chan->datasheet_name = chan_name_ain[chan->channel];
123 chan->scan_type.sign = 'u';
124 chan->scan_type.realbits = 12;
125 chan->scan_type.storagebits = 32;
128 indio_dev->channels = chan_array;
133 static void tiadc_channels_remove(struct iio_dev *indio_dev)
135 kfree(indio_dev->channels);
138 static int tiadc_read_raw(struct iio_dev *indio_dev,
139 struct iio_chan_spec const *chan,
140 int *val, int *val2, long mask)
142 struct tiadc_device *adc_dev = iio_priv(indio_dev);
144 unsigned int fifo1count, read, stepid;
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);
153 /* Wait for ADC sequencer to complete sampling */
154 while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
155 if (time_after(jiffies, timeout))
158 map_val = chan->channel + TOTAL_CHANNELS;
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.
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];
177 if (WARN_ON_ONCE(step == UINT_MAX))
180 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
181 for (i = 0; i < fifo1count; i++) {
182 read = tiadc_readl(adc_dev, REG_FIFO1);
183 stepid = read & FIFOREAD_CHNLID_MASK;
184 stepid = stepid >> 0x10;
186 if (stepid == map_val) {
187 read = read & FIFOREAD_DATA_MASK;
198 static const struct iio_info tiadc_info = {
199 .read_raw = &tiadc_read_raw,
200 .driver_module = THIS_MODULE,
203 static int tiadc_probe(struct platform_device *pdev)
205 struct iio_dev *indio_dev;
206 struct tiadc_device *adc_dev;
207 struct device_node *node = pdev->dev.of_node;
208 struct property *prop;
215 dev_err(&pdev->dev, "Could not find valid DT data.\n");
219 indio_dev = devm_iio_device_alloc(&pdev->dev,
220 sizeof(struct tiadc_device));
221 if (indio_dev == NULL) {
222 dev_err(&pdev->dev, "failed to allocate iio device\n");
225 adc_dev = iio_priv(indio_dev);
227 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
229 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
230 adc_dev->channel_line[channels] = val;
233 adc_dev->channels = channels;
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;
240 tiadc_step_config(adc_dev);
242 err = tiadc_channel_init(indio_dev, adc_dev->channels);
246 err = iio_device_register(indio_dev);
248 goto err_free_channels;
250 platform_set_drvdata(pdev, indio_dev);
255 tiadc_channels_remove(indio_dev);
259 static int tiadc_remove(struct platform_device *pdev)
261 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
262 struct tiadc_device *adc_dev = iio_priv(indio_dev);
265 iio_device_unregister(indio_dev);
266 tiadc_channels_remove(indio_dev);
268 step_en = get_adc_step_mask(adc_dev);
269 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
275 static int tiadc_suspend(struct device *dev)
277 struct iio_dev *indio_dev = dev_get_drvdata(dev);
278 struct tiadc_device *adc_dev = iio_priv(indio_dev);
279 struct ti_tscadc_dev *tscadc_dev;
282 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
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));
293 static int tiadc_resume(struct device *dev)
295 struct iio_dev *indio_dev = dev_get_drvdata(dev);
296 struct tiadc_device *adc_dev = iio_priv(indio_dev);
297 unsigned int restore;
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);
304 tiadc_step_config(adc_dev);
309 static const struct dev_pm_ops tiadc_pm_ops = {
310 .suspend = tiadc_suspend,
311 .resume = tiadc_resume,
313 #define TIADC_PM_OPS (&tiadc_pm_ops)
315 #define TIADC_PM_OPS NULL
318 static const struct of_device_id ti_adc_dt_ids[] = {
319 { .compatible = "ti,am3359-adc", },
322 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
324 static struct platform_driver tiadc_driver = {
326 .name = "TI-am335x-adc",
327 .owner = THIS_MODULE,
329 .of_match_table = of_match_ptr(ti_adc_dt_ids),
331 .probe = tiadc_probe,
332 .remove = tiadc_remove,
334 module_platform_driver(tiadc_driver);
336 MODULE_DESCRIPTION("TI ADC controller driver");
337 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
338 MODULE_LICENSE("GPL");