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(indio_dev);
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;
266 ret = iio_buffer_register(indio_dev,
268 indio_dev->num_channels);
275 free_irq(irq, indio_dev);
277 iio_kfifo_free(indio_dev->buffer);
281 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
283 struct tiadc_device *adc_dev = iio_priv(indio_dev);
285 free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
286 iio_kfifo_free(indio_dev->buffer);
287 iio_buffer_unregister(indio_dev);
291 static const char * const chan_name_ain[] = {
302 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
304 struct tiadc_device *adc_dev = iio_priv(indio_dev);
305 struct iio_chan_spec *chan_array;
306 struct iio_chan_spec *chan;
309 indio_dev->num_channels = channels;
310 chan_array = kcalloc(channels,
311 sizeof(struct iio_chan_spec), GFP_KERNEL);
312 if (chan_array == NULL)
316 for (i = 0; i < channels; i++, chan++) {
318 chan->type = IIO_VOLTAGE;
320 chan->channel = adc_dev->channel_line[i];
321 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
322 chan->datasheet_name = chan_name_ain[chan->channel];
323 chan->scan_index = i;
324 chan->scan_type.sign = 'u';
325 chan->scan_type.realbits = 12;
326 chan->scan_type.storagebits = 16;
329 indio_dev->channels = chan_array;
334 static void tiadc_channels_remove(struct iio_dev *indio_dev)
336 kfree(indio_dev->channels);
339 static int tiadc_read_raw(struct iio_dev *indio_dev,
340 struct iio_chan_spec const *chan,
341 int *val, int *val2, long mask)
343 struct tiadc_device *adc_dev = iio_priv(indio_dev);
345 unsigned int fifo1count, read, stepid;
348 unsigned long timeout;
350 if (iio_buffer_enabled(indio_dev))
353 step_en = get_adc_chan_step_mask(adc_dev, chan);
357 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
359 tiadc_readl(adc_dev, REG_FIFO1);
361 am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
363 timeout = jiffies + usecs_to_jiffies
364 (IDLE_TIMEOUT * adc_dev->channels);
365 /* Wait for Fifo threshold interrupt */
367 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
371 if (time_after(jiffies, timeout)) {
372 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
376 map_val = adc_dev->channel_step[chan->scan_index];
379 * We check the complete FIFO. We programmed just one entry but in case
380 * something went wrong we left empty handed (-EAGAIN previously) and
381 * then the value apeared somehow in the FIFO we would have two entries.
382 * Therefore we read every item and keep only the latest version of the
385 for (i = 0; i < fifo1count; i++) {
386 read = tiadc_readl(adc_dev, REG_FIFO1);
387 stepid = read & FIFOREAD_CHNLID_MASK;
388 stepid = stepid >> 0x10;
390 if (stepid == map_val) {
391 read = read & FIFOREAD_DATA_MASK;
396 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
403 static const struct iio_info tiadc_info = {
404 .read_raw = &tiadc_read_raw,
405 .driver_module = THIS_MODULE,
408 static int tiadc_probe(struct platform_device *pdev)
410 struct iio_dev *indio_dev;
411 struct tiadc_device *adc_dev;
412 struct device_node *node = pdev->dev.of_node;
413 struct property *prop;
420 dev_err(&pdev->dev, "Could not find valid DT data.\n");
424 indio_dev = devm_iio_device_alloc(&pdev->dev,
425 sizeof(struct tiadc_device));
426 if (indio_dev == NULL) {
427 dev_err(&pdev->dev, "failed to allocate iio device\n");
430 adc_dev = iio_priv(indio_dev);
432 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
434 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
435 adc_dev->channel_line[channels] = val;
438 adc_dev->channels = channels;
440 indio_dev->dev.parent = &pdev->dev;
441 indio_dev->name = dev_name(&pdev->dev);
442 indio_dev->modes = INDIO_DIRECT_MODE;
443 indio_dev->info = &tiadc_info;
445 tiadc_step_config(indio_dev);
446 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
448 err = tiadc_channel_init(indio_dev, adc_dev->channels);
452 err = tiadc_iio_buffered_hardware_setup(indio_dev,
455 adc_dev->mfd_tscadc->irq,
457 &tiadc_buffer_setup_ops);
460 goto err_free_channels;
462 err = iio_device_register(indio_dev);
464 goto err_buffer_unregister;
466 platform_set_drvdata(pdev, indio_dev);
470 err_buffer_unregister:
471 tiadc_iio_buffered_hardware_remove(indio_dev);
473 tiadc_channels_remove(indio_dev);
477 static int tiadc_remove(struct platform_device *pdev)
479 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
480 struct tiadc_device *adc_dev = iio_priv(indio_dev);
483 iio_device_unregister(indio_dev);
484 tiadc_iio_buffered_hardware_remove(indio_dev);
485 tiadc_channels_remove(indio_dev);
487 step_en = get_adc_step_mask(adc_dev);
488 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
494 static int tiadc_suspend(struct device *dev)
496 struct iio_dev *indio_dev = dev_get_drvdata(dev);
497 struct tiadc_device *adc_dev = iio_priv(indio_dev);
498 struct ti_tscadc_dev *tscadc_dev;
501 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
502 if (!device_may_wakeup(tscadc_dev->dev)) {
503 idle = tiadc_readl(adc_dev, REG_CTRL);
504 idle &= ~(CNTRLREG_TSCSSENB);
505 tiadc_writel(adc_dev, REG_CTRL, (idle |
506 CNTRLREG_POWERDOWN));
512 static int tiadc_resume(struct device *dev)
514 struct iio_dev *indio_dev = dev_get_drvdata(dev);
515 struct tiadc_device *adc_dev = iio_priv(indio_dev);
516 unsigned int restore;
518 /* Make sure ADC is powered up */
519 restore = tiadc_readl(adc_dev, REG_CTRL);
520 restore &= ~(CNTRLREG_POWERDOWN);
521 tiadc_writel(adc_dev, REG_CTRL, restore);
523 tiadc_step_config(indio_dev);
524 am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
525 adc_dev->buffer_en_ch_steps);
529 static const struct dev_pm_ops tiadc_pm_ops = {
530 .suspend = tiadc_suspend,
531 .resume = tiadc_resume,
533 #define TIADC_PM_OPS (&tiadc_pm_ops)
535 #define TIADC_PM_OPS NULL
538 static const struct of_device_id ti_adc_dt_ids[] = {
539 { .compatible = "ti,am3359-adc", },
542 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
544 static struct platform_driver tiadc_driver = {
546 .name = "TI-am335x-adc",
548 .of_match_table = ti_adc_dt_ids,
550 .probe = tiadc_probe,
551 .remove = tiadc_remove,
553 module_platform_driver(tiadc_driver);
555 MODULE_DESCRIPTION("TI ADC controller driver");
556 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
557 MODULE_LICENSE("GPL");