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>
31 #include <linux/iio/buffer.h>
32 #include <linux/iio/kfifo_buf.h>
35 struct ti_tscadc_dev *mfd_tscadc;
39 int buffer_en_ch_steps;
43 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
45 return readl(adc->mfd_tscadc->tscadc_base + reg);
48 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
51 writel(val, adc->mfd_tscadc->tscadc_base + reg);
54 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
58 step_en = ((1 << adc_dev->channels) - 1);
59 step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
63 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
65 return 1 << adc_dev->channel_step[chan];
68 static void tiadc_step_config(struct iio_dev *indio_dev)
70 struct tiadc_device *adc_dev = iio_priv(indio_dev);
71 unsigned int stepconfig;
75 * There are 16 configurable steps and 8 analog input
76 * lines available which are shared between Touchscreen and ADC.
78 * Steps backwards i.e. from 16 towards 0 are used by ADC
79 * depending on number of input lines needed.
80 * Channel would represent which analog input
81 * needs to be given to ADC to digitalize data.
84 steps = TOTAL_STEPS - adc_dev->channels;
85 if (iio_buffer_enabled(indio_dev))
86 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
87 | STEPCONFIG_MODE_SWCNT;
89 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
91 for (i = 0; i < adc_dev->channels; i++) {
94 chan = adc_dev->channel_line[i];
95 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
96 stepconfig | STEPCONFIG_INP(chan));
97 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
99 adc_dev->channel_step[i] = steps;
104 static irqreturn_t tiadc_irq_h(int irq, void *private)
106 struct iio_dev *indio_dev = private;
107 struct tiadc_device *adc_dev = iio_priv(indio_dev);
108 unsigned int status, config;
109 status = tiadc_readl(adc_dev, REG_IRQSTATUS);
112 * ADC and touchscreen share the IRQ line.
113 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
115 if (status & IRQENB_FIFO1OVRRUN) {
116 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
117 config = tiadc_readl(adc_dev, REG_CTRL);
118 config &= ~(CNTRLREG_TSCSSENB);
119 tiadc_writel(adc_dev, REG_CTRL, config);
120 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
121 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
122 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
124 } else if (status & IRQENB_FIFO1THRES) {
125 /* Disable irq and wake worker thread */
126 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
127 return IRQ_WAKE_THREAD;
133 static irqreturn_t tiadc_worker_h(int irq, void *private)
135 struct iio_dev *indio_dev = private;
136 struct tiadc_device *adc_dev = iio_priv(indio_dev);
137 int i, k, fifo1count, read;
138 u16 *data = adc_dev->data;
140 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
141 for (k = 0; k < fifo1count; k = k + i) {
142 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
143 read = tiadc_readl(adc_dev, REG_FIFO1);
144 data[i] = read & FIFOREAD_DATA_MASK;
146 iio_push_to_buffers(indio_dev, (u8 *) data);
149 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
150 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
155 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
157 struct tiadc_device *adc_dev = iio_priv(indio_dev);
158 int i, fifo1count, read;
160 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
162 IRQENB_FIFO1UNDRFLW));
164 /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
165 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
166 for (i = 0; i < fifo1count; i++)
167 read = tiadc_readl(adc_dev, REG_FIFO1);
172 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
174 struct tiadc_device *adc_dev = iio_priv(indio_dev);
175 struct iio_buffer *buffer = indio_dev->buffer;
176 unsigned int enb = 0;
179 tiadc_step_config(indio_dev);
180 for_each_set_bit(bit, buffer->scan_mask, adc_dev->channels)
181 enb |= (get_adc_step_bit(adc_dev, bit) << 1);
182 adc_dev->buffer_en_ch_steps = enb;
184 am335x_tsc_se_set(adc_dev->mfd_tscadc, enb);
186 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES
187 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
188 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES
189 | IRQENB_FIFO1OVRRUN);
194 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
196 struct tiadc_device *adc_dev = iio_priv(indio_dev);
197 int fifo1count, i, read;
199 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
200 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
201 am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
203 /* Flush FIFO of leftover data in the time it takes to disable adc */
204 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
205 for (i = 0; i < fifo1count; i++)
206 read = tiadc_readl(adc_dev, REG_FIFO1);
211 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
213 tiadc_step_config(indio_dev);
218 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
219 .preenable = &tiadc_buffer_preenable,
220 .postenable = &tiadc_buffer_postenable,
221 .predisable = &tiadc_buffer_predisable,
222 .postdisable = &tiadc_buffer_postdisable,
225 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
226 irqreturn_t (*pollfunc_bh)(int irq, void *p),
227 irqreturn_t (*pollfunc_th)(int irq, void *p),
230 const struct iio_buffer_setup_ops *setup_ops)
234 indio_dev->buffer = iio_kfifo_allocate(indio_dev);
235 if (!indio_dev->buffer)
238 ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
239 flags, indio_dev->name, indio_dev);
241 goto error_kfifo_free;
243 indio_dev->setup_ops = setup_ops;
244 indio_dev->modes |= INDIO_BUFFER_HARDWARE;
246 ret = iio_buffer_register(indio_dev,
248 indio_dev->num_channels);
255 free_irq(irq, indio_dev);
257 iio_kfifo_free(indio_dev->buffer);
261 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
263 struct tiadc_device *adc_dev = iio_priv(indio_dev);
265 free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
266 iio_kfifo_free(indio_dev->buffer);
267 iio_buffer_unregister(indio_dev);
271 static const char * const chan_name_ain[] = {
282 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
284 struct tiadc_device *adc_dev = iio_priv(indio_dev);
285 struct iio_chan_spec *chan_array;
286 struct iio_chan_spec *chan;
289 indio_dev->num_channels = channels;
290 chan_array = kcalloc(channels,
291 sizeof(struct iio_chan_spec), GFP_KERNEL);
292 if (chan_array == NULL)
296 for (i = 0; i < channels; i++, chan++) {
298 chan->type = IIO_VOLTAGE;
300 chan->channel = adc_dev->channel_line[i];
301 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
302 chan->datasheet_name = chan_name_ain[chan->channel];
303 chan->scan_index = i;
304 chan->scan_type.sign = 'u';
305 chan->scan_type.realbits = 12;
306 chan->scan_type.storagebits = 16;
309 indio_dev->channels = chan_array;
314 static void tiadc_channels_remove(struct iio_dev *indio_dev)
316 kfree(indio_dev->channels);
319 static int tiadc_read_raw(struct iio_dev *indio_dev,
320 struct iio_chan_spec const *chan,
321 int *val, int *val2, long mask)
323 struct tiadc_device *adc_dev = iio_priv(indio_dev);
325 unsigned int fifo1count, read, stepid;
328 unsigned long timeout = jiffies + usecs_to_jiffies
329 (IDLE_TIMEOUT * adc_dev->channels);
331 if (iio_buffer_enabled(indio_dev))
334 step_en = get_adc_step_mask(adc_dev);
335 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
337 /* Wait for ADC sequencer to complete sampling */
338 while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
339 if (time_after(jiffies, timeout))
342 map_val = chan->channel + TOTAL_CHANNELS;
345 * When the sub-system is first enabled,
346 * the sequencer will always start with the
347 * lowest step (1) and continue until step (16).
348 * For ex: If we have enabled 4 ADC channels and
349 * currently use only 1 out of them, the
350 * sequencer still configures all the 4 steps,
351 * leading to 3 unwanted data.
352 * Hence we need to flush out this data.
355 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
356 for (i = 0; i < fifo1count; i++) {
357 read = tiadc_readl(adc_dev, REG_FIFO1);
358 stepid = read & FIFOREAD_CHNLID_MASK;
359 stepid = stepid >> 0x10;
361 if (stepid == map_val) {
362 read = read & FIFOREAD_DATA_MASK;
373 static const struct iio_info tiadc_info = {
374 .read_raw = &tiadc_read_raw,
375 .driver_module = THIS_MODULE,
378 static int tiadc_probe(struct platform_device *pdev)
380 struct iio_dev *indio_dev;
381 struct tiadc_device *adc_dev;
382 struct device_node *node = pdev->dev.of_node;
383 struct property *prop;
390 dev_err(&pdev->dev, "Could not find valid DT data.\n");
394 indio_dev = devm_iio_device_alloc(&pdev->dev,
395 sizeof(struct tiadc_device));
396 if (indio_dev == NULL) {
397 dev_err(&pdev->dev, "failed to allocate iio device\n");
400 adc_dev = iio_priv(indio_dev);
402 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
404 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
405 adc_dev->channel_line[channels] = val;
408 adc_dev->channels = channels;
410 indio_dev->dev.parent = &pdev->dev;
411 indio_dev->name = dev_name(&pdev->dev);
412 indio_dev->modes = INDIO_DIRECT_MODE;
413 indio_dev->info = &tiadc_info;
415 tiadc_step_config(indio_dev);
416 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
418 err = tiadc_channel_init(indio_dev, adc_dev->channels);
422 err = tiadc_iio_buffered_hardware_setup(indio_dev,
425 adc_dev->mfd_tscadc->irq,
427 &tiadc_buffer_setup_ops);
430 goto err_free_channels;
432 err = iio_device_register(indio_dev);
434 goto err_buffer_unregister;
436 platform_set_drvdata(pdev, indio_dev);
440 err_buffer_unregister:
441 tiadc_iio_buffered_hardware_remove(indio_dev);
443 tiadc_channels_remove(indio_dev);
447 static int tiadc_remove(struct platform_device *pdev)
449 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
450 struct tiadc_device *adc_dev = iio_priv(indio_dev);
453 iio_device_unregister(indio_dev);
454 tiadc_iio_buffered_hardware_remove(indio_dev);
455 tiadc_channels_remove(indio_dev);
457 step_en = get_adc_step_mask(adc_dev);
458 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
464 static int tiadc_suspend(struct device *dev)
466 struct iio_dev *indio_dev = dev_get_drvdata(dev);
467 struct tiadc_device *adc_dev = iio_priv(indio_dev);
468 struct ti_tscadc_dev *tscadc_dev;
471 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
472 if (!device_may_wakeup(tscadc_dev->dev)) {
473 idle = tiadc_readl(adc_dev, REG_CTRL);
474 idle &= ~(CNTRLREG_TSCSSENB);
475 tiadc_writel(adc_dev, REG_CTRL, (idle |
476 CNTRLREG_POWERDOWN));
482 static int tiadc_resume(struct device *dev)
484 struct iio_dev *indio_dev = dev_get_drvdata(dev);
485 struct tiadc_device *adc_dev = iio_priv(indio_dev);
486 unsigned int restore;
488 /* Make sure ADC is powered up */
489 restore = tiadc_readl(adc_dev, REG_CTRL);
490 restore &= ~(CNTRLREG_POWERDOWN);
491 tiadc_writel(adc_dev, REG_CTRL, restore);
493 tiadc_step_config(indio_dev);
498 static const struct dev_pm_ops tiadc_pm_ops = {
499 .suspend = tiadc_suspend,
500 .resume = tiadc_resume,
502 #define TIADC_PM_OPS (&tiadc_pm_ops)
504 #define TIADC_PM_OPS NULL
507 static const struct of_device_id ti_adc_dt_ids[] = {
508 { .compatible = "ti,am3359-adc", },
511 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
513 static struct platform_driver tiadc_driver = {
515 .name = "TI-am335x-adc",
516 .owner = THIS_MODULE,
518 .of_match_table = ti_adc_dt_ids,
520 .probe = tiadc_probe,
521 .remove = tiadc_remove,
523 module_platform_driver(tiadc_driver);
525 MODULE_DESCRIPTION("TI ADC controller driver");
526 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
527 MODULE_LICENSE("GPL");