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/kernel.h>
17 #include <linux/err.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <linux/interrupt.h>
21 #include <linux/platform_device.h>
23 #include <linux/iio/iio.h>
25 #include <linux/of_device.h>
26 #include <linux/iio/machine.h>
27 #include <linux/iio/driver.h>
29 #include <linux/mfd/ti_am335x_tscadc.h>
30 #include <linux/iio/buffer.h>
31 #include <linux/iio/kfifo_buf.h>
34 struct ti_tscadc_dev *mfd_tscadc;
38 int buffer_en_ch_steps;
42 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
44 return readl(adc->mfd_tscadc->tscadc_base + reg);
47 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
50 writel(val, adc->mfd_tscadc->tscadc_base + reg);
53 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
57 step_en = ((1 << adc_dev->channels) - 1);
58 step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
62 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
63 struct iio_chan_spec const *chan)
67 for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
68 if (chan->channel == adc_dev->channel_line[i]) {
71 step = adc_dev->channel_step[i];
72 /* +1 for the charger */
73 return 1 << (step + 1);
80 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
82 return 1 << adc_dev->channel_step[chan];
85 static void tiadc_step_config(struct iio_dev *indio_dev)
87 struct tiadc_device *adc_dev = iio_priv(indio_dev);
88 unsigned int stepconfig;
92 * There are 16 configurable steps and 8 analog input
93 * lines available which are shared between Touchscreen and ADC.
95 * Steps forwards i.e. from 0 towards 16 are used by ADC
96 * depending on number of input lines needed.
97 * Channel would represent which analog input
98 * needs to be given to ADC to digitalize data.
101 if (iio_buffer_enabled(indio_dev))
102 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
103 | STEPCONFIG_MODE_SWCNT;
105 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
107 for (i = 0; i < adc_dev->channels; i++) {
110 chan = adc_dev->channel_line[i];
111 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
112 stepconfig | STEPCONFIG_INP(chan));
113 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
115 adc_dev->channel_step[i] = steps;
120 static irqreturn_t tiadc_irq_h(int irq, void *private)
122 struct iio_dev *indio_dev = private;
123 struct tiadc_device *adc_dev = iio_priv(indio_dev);
124 unsigned int status, config;
125 status = tiadc_readl(adc_dev, REG_IRQSTATUS);
128 * ADC and touchscreen share the IRQ line.
129 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
131 if (status & IRQENB_FIFO1OVRRUN) {
132 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
133 config = tiadc_readl(adc_dev, REG_CTRL);
134 config &= ~(CNTRLREG_TSCSSENB);
135 tiadc_writel(adc_dev, REG_CTRL, config);
136 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
137 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
138 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
140 } else if (status & IRQENB_FIFO1THRES) {
141 /* Disable irq and wake worker thread */
142 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
143 return IRQ_WAKE_THREAD;
149 static irqreturn_t tiadc_worker_h(int irq, void *private)
151 struct iio_dev *indio_dev = private;
152 struct tiadc_device *adc_dev = iio_priv(indio_dev);
153 int i, k, fifo1count, read;
154 u16 *data = adc_dev->data;
156 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
157 for (k = 0; k < fifo1count; k = k + i) {
158 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
159 read = tiadc_readl(adc_dev, REG_FIFO1);
160 data[i] = read & FIFOREAD_DATA_MASK;
162 iio_push_to_buffers(indio_dev, (u8 *) data);
165 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
166 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
171 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
173 struct tiadc_device *adc_dev = iio_priv(indio_dev);
174 int i, fifo1count, read;
176 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
178 IRQENB_FIFO1UNDRFLW));
180 /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
181 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
182 for (i = 0; i < fifo1count; i++)
183 read = tiadc_readl(adc_dev, REG_FIFO1);
188 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
190 struct tiadc_device *adc_dev = iio_priv(indio_dev);
191 struct iio_buffer *buffer = indio_dev->buffer;
192 unsigned int enb = 0;
195 tiadc_step_config(indio_dev);
196 for_each_set_bit(bit, buffer->scan_mask, adc_dev->channels)
197 enb |= (get_adc_step_bit(adc_dev, bit) << 1);
198 adc_dev->buffer_en_ch_steps = enb;
200 am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
202 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES
203 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
204 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES
205 | IRQENB_FIFO1OVRRUN);
210 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
212 struct tiadc_device *adc_dev = iio_priv(indio_dev);
213 int fifo1count, i, read;
215 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
216 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
217 am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
218 adc_dev->buffer_en_ch_steps = 0;
220 /* Flush FIFO of leftover data in the time it takes to disable adc */
221 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
222 for (i = 0; i < fifo1count; i++)
223 read = tiadc_readl(adc_dev, REG_FIFO1);
228 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
230 tiadc_step_config(indio_dev);
235 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
236 .preenable = &tiadc_buffer_preenable,
237 .postenable = &tiadc_buffer_postenable,
238 .predisable = &tiadc_buffer_predisable,
239 .postdisable = &tiadc_buffer_postdisable,
242 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
243 irqreturn_t (*pollfunc_bh)(int irq, void *p),
244 irqreturn_t (*pollfunc_th)(int irq, void *p),
247 const struct iio_buffer_setup_ops *setup_ops)
249 struct iio_buffer *buffer;
252 buffer = iio_kfifo_allocate();
256 iio_device_attach_buffer(indio_dev, buffer);
258 ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
259 flags, indio_dev->name, indio_dev);
261 goto error_kfifo_free;
263 indio_dev->setup_ops = setup_ops;
264 indio_dev->modes |= INDIO_BUFFER_HARDWARE;
269 iio_kfifo_free(indio_dev->buffer);
273 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
275 struct tiadc_device *adc_dev = iio_priv(indio_dev);
277 free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
278 iio_kfifo_free(indio_dev->buffer);
282 static const char * const chan_name_ain[] = {
293 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
295 struct tiadc_device *adc_dev = iio_priv(indio_dev);
296 struct iio_chan_spec *chan_array;
297 struct iio_chan_spec *chan;
300 indio_dev->num_channels = channels;
301 chan_array = kcalloc(channels,
302 sizeof(struct iio_chan_spec), GFP_KERNEL);
303 if (chan_array == NULL)
307 for (i = 0; i < channels; i++, chan++) {
309 chan->type = IIO_VOLTAGE;
311 chan->channel = adc_dev->channel_line[i];
312 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
313 chan->datasheet_name = chan_name_ain[chan->channel];
314 chan->scan_index = i;
315 chan->scan_type.sign = 'u';
316 chan->scan_type.realbits = 12;
317 chan->scan_type.storagebits = 16;
320 indio_dev->channels = chan_array;
325 static void tiadc_channels_remove(struct iio_dev *indio_dev)
327 kfree(indio_dev->channels);
330 static int tiadc_read_raw(struct iio_dev *indio_dev,
331 struct iio_chan_spec const *chan,
332 int *val, int *val2, long mask)
334 struct tiadc_device *adc_dev = iio_priv(indio_dev);
336 unsigned int fifo1count, read, stepid;
339 unsigned long timeout;
341 if (iio_buffer_enabled(indio_dev))
344 step_en = get_adc_chan_step_mask(adc_dev, chan);
348 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
350 tiadc_readl(adc_dev, REG_FIFO1);
352 am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
354 timeout = jiffies + usecs_to_jiffies
355 (IDLE_TIMEOUT * adc_dev->channels);
356 /* Wait for Fifo threshold interrupt */
358 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
362 if (time_after(jiffies, timeout)) {
363 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
367 map_val = adc_dev->channel_step[chan->scan_index];
370 * We check the complete FIFO. We programmed just one entry but in case
371 * something went wrong we left empty handed (-EAGAIN previously) and
372 * then the value apeared somehow in the FIFO we would have two entries.
373 * Therefore we read every item and keep only the latest version of the
376 for (i = 0; i < fifo1count; i++) {
377 read = tiadc_readl(adc_dev, REG_FIFO1);
378 stepid = read & FIFOREAD_CHNLID_MASK;
379 stepid = stepid >> 0x10;
381 if (stepid == map_val) {
382 read = read & FIFOREAD_DATA_MASK;
387 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
394 static const struct iio_info tiadc_info = {
395 .read_raw = &tiadc_read_raw,
396 .driver_module = THIS_MODULE,
399 static int tiadc_probe(struct platform_device *pdev)
401 struct iio_dev *indio_dev;
402 struct tiadc_device *adc_dev;
403 struct device_node *node = pdev->dev.of_node;
404 struct property *prop;
411 dev_err(&pdev->dev, "Could not find valid DT data.\n");
415 indio_dev = devm_iio_device_alloc(&pdev->dev,
416 sizeof(struct tiadc_device));
417 if (indio_dev == NULL) {
418 dev_err(&pdev->dev, "failed to allocate iio device\n");
421 adc_dev = iio_priv(indio_dev);
423 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
425 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
426 adc_dev->channel_line[channels] = val;
429 adc_dev->channels = channels;
431 indio_dev->dev.parent = &pdev->dev;
432 indio_dev->name = dev_name(&pdev->dev);
433 indio_dev->modes = INDIO_DIRECT_MODE;
434 indio_dev->info = &tiadc_info;
436 tiadc_step_config(indio_dev);
437 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
439 err = tiadc_channel_init(indio_dev, adc_dev->channels);
443 err = tiadc_iio_buffered_hardware_setup(indio_dev,
446 adc_dev->mfd_tscadc->irq,
448 &tiadc_buffer_setup_ops);
451 goto err_free_channels;
453 err = iio_device_register(indio_dev);
455 goto err_buffer_unregister;
457 platform_set_drvdata(pdev, indio_dev);
461 err_buffer_unregister:
462 tiadc_iio_buffered_hardware_remove(indio_dev);
464 tiadc_channels_remove(indio_dev);
468 static int tiadc_remove(struct platform_device *pdev)
470 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
471 struct tiadc_device *adc_dev = iio_priv(indio_dev);
474 iio_device_unregister(indio_dev);
475 tiadc_iio_buffered_hardware_remove(indio_dev);
476 tiadc_channels_remove(indio_dev);
478 step_en = get_adc_step_mask(adc_dev);
479 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
485 static int tiadc_suspend(struct device *dev)
487 struct iio_dev *indio_dev = dev_get_drvdata(dev);
488 struct tiadc_device *adc_dev = iio_priv(indio_dev);
489 struct ti_tscadc_dev *tscadc_dev;
492 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
493 if (!device_may_wakeup(tscadc_dev->dev)) {
494 idle = tiadc_readl(adc_dev, REG_CTRL);
495 idle &= ~(CNTRLREG_TSCSSENB);
496 tiadc_writel(adc_dev, REG_CTRL, (idle |
497 CNTRLREG_POWERDOWN));
503 static int tiadc_resume(struct device *dev)
505 struct iio_dev *indio_dev = dev_get_drvdata(dev);
506 struct tiadc_device *adc_dev = iio_priv(indio_dev);
507 unsigned int restore;
509 /* Make sure ADC is powered up */
510 restore = tiadc_readl(adc_dev, REG_CTRL);
511 restore &= ~(CNTRLREG_POWERDOWN);
512 tiadc_writel(adc_dev, REG_CTRL, restore);
514 tiadc_step_config(indio_dev);
515 am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
516 adc_dev->buffer_en_ch_steps);
520 static const struct dev_pm_ops tiadc_pm_ops = {
521 .suspend = tiadc_suspend,
522 .resume = tiadc_resume,
524 #define TIADC_PM_OPS (&tiadc_pm_ops)
526 #define TIADC_PM_OPS NULL
529 static const struct of_device_id ti_adc_dt_ids[] = {
530 { .compatible = "ti,am3359-adc", },
533 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
535 static struct platform_driver tiadc_driver = {
537 .name = "TI-am335x-adc",
539 .of_match_table = ti_adc_dt_ids,
541 .probe = tiadc_probe,
542 .remove = tiadc_remove,
544 module_platform_driver(tiadc_driver);
546 MODULE_DESCRIPTION("TI ADC controller driver");
547 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
548 MODULE_LICENSE("GPL");