2 * Driver for the ADC present in the Atmel AT91 evaluation boards.
4 * Copyright 2011 Free Electrons
6 * Licensed under the GPLv2 or later.
9 #include <linux/bitmap.h>
10 #include <linux/bitops.h>
11 #include <linux/clk.h>
12 #include <linux/err.h>
14 #include <linux/interrupt.h>
15 #include <linux/jiffies.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
19 #include <linux/of_device.h>
20 #include <linux/platform_device.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/wait.h>
25 #include <linux/platform_data/at91_adc.h>
27 #include <linux/iio/iio.h>
28 #include <linux/iio/buffer.h>
29 #include <linux/iio/trigger.h>
30 #include <linux/iio/trigger_consumer.h>
31 #include <linux/iio/triggered_buffer.h>
33 #include <mach/at91_adc.h>
35 #define AT91_ADC_CHAN(st, ch) \
36 (st->registers->channel_base + (ch * 4))
37 #define at91_adc_readl(st, reg) \
38 (readl_relaxed(st->reg_base + reg))
39 #define at91_adc_writel(st, reg, val) \
40 (writel_relaxed(val, st->reg_base + reg))
42 struct at91_adc_state
{
45 unsigned long channels_mask
;
52 void __iomem
*reg_base
;
53 struct at91_adc_reg_desc
*registers
;
55 struct iio_trigger
**trig
;
56 struct at91_adc_trigger
*trigger_list
;
60 wait_queue_head_t wq_data_avail
;
63 static irqreturn_t
at91_adc_trigger_handler(int irq
, void *p
)
65 struct iio_poll_func
*pf
= p
;
66 struct iio_dev
*idev
= pf
->indio_dev
;
67 struct at91_adc_state
*st
= iio_priv(idev
);
70 for (i
= 0; i
< idev
->masklength
; i
++) {
71 if (!test_bit(i
, idev
->active_scan_mask
))
73 st
->buffer
[j
] = at91_adc_readl(st
, AT91_ADC_CHAN(st
, i
));
77 if (idev
->scan_timestamp
) {
78 s64
*timestamp
= (s64
*)((u8
*)st
->buffer
+
79 ALIGN(j
, sizeof(s64
)));
80 *timestamp
= pf
->timestamp
;
83 iio_push_to_buffers(idev
, (u8
*)st
->buffer
);
85 iio_trigger_notify_done(idev
->trig
);
87 /* Needed to ACK the DRDY interruption */
88 at91_adc_readl(st
, AT91_ADC_LCDR
);
95 static irqreturn_t
at91_adc_eoc_trigger(int irq
, void *private)
97 struct iio_dev
*idev
= private;
98 struct at91_adc_state
*st
= iio_priv(idev
);
99 u32 status
= at91_adc_readl(st
, st
->registers
->status_register
);
101 if (!(status
& st
->registers
->drdy_mask
))
104 if (iio_buffer_enabled(idev
)) {
105 disable_irq_nosync(irq
);
106 iio_trigger_poll(idev
->trig
, iio_get_time_ns());
108 st
->last_value
= at91_adc_readl(st
, AT91_ADC_LCDR
);
110 wake_up_interruptible(&st
->wq_data_avail
);
116 static int at91_adc_channel_init(struct iio_dev
*idev
)
118 struct at91_adc_state
*st
= iio_priv(idev
);
119 struct iio_chan_spec
*chan_array
, *timestamp
;
122 idev
->num_channels
= bitmap_weight(&st
->channels_mask
,
123 st
->num_channels
) + 1;
125 chan_array
= devm_kzalloc(&idev
->dev
,
126 ((idev
->num_channels
+ 1) *
127 sizeof(struct iio_chan_spec
)),
133 for_each_set_bit(bit
, &st
->channels_mask
, st
->num_channels
) {
134 struct iio_chan_spec
*chan
= chan_array
+ idx
;
136 chan
->type
= IIO_VOLTAGE
;
139 chan
->scan_index
= idx
;
140 chan
->scan_type
.sign
= 'u';
141 chan
->scan_type
.realbits
= 10;
142 chan
->scan_type
.storagebits
= 16;
143 chan
->info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_SCALE
);
144 chan
->info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
);
147 timestamp
= chan_array
+ idx
;
149 timestamp
->type
= IIO_TIMESTAMP
;
150 timestamp
->channel
= -1;
151 timestamp
->scan_index
= idx
;
152 timestamp
->scan_type
.sign
= 's';
153 timestamp
->scan_type
.realbits
= 64;
154 timestamp
->scan_type
.storagebits
= 64;
156 idev
->channels
= chan_array
;
157 return idev
->num_channels
;
160 static u8
at91_adc_get_trigger_value_by_name(struct iio_dev
*idev
,
161 struct at91_adc_trigger
*triggers
,
162 const char *trigger_name
)
164 struct at91_adc_state
*st
= iio_priv(idev
);
168 for (i
= 0; i
< st
->trigger_number
; i
++) {
169 char *name
= kasprintf(GFP_KERNEL
,
177 if (strcmp(trigger_name
, name
) == 0) {
178 value
= triggers
[i
].value
;
189 static int at91_adc_configure_trigger(struct iio_trigger
*trig
, bool state
)
191 struct iio_dev
*idev
= trig
->private_data
;
192 struct at91_adc_state
*st
= iio_priv(idev
);
193 struct iio_buffer
*buffer
= idev
->buffer
;
194 struct at91_adc_reg_desc
*reg
= st
->registers
;
195 u32 status
= at91_adc_readl(st
, reg
->trigger_register
);
199 value
= at91_adc_get_trigger_value_by_name(idev
,
206 st
->buffer
= kmalloc(idev
->scan_bytes
, GFP_KERNEL
);
207 if (st
->buffer
== NULL
)
210 at91_adc_writel(st
, reg
->trigger_register
,
213 for_each_set_bit(bit
, buffer
->scan_mask
,
215 struct iio_chan_spec
const *chan
= idev
->channels
+ bit
;
216 at91_adc_writel(st
, AT91_ADC_CHER
,
217 AT91_ADC_CH(chan
->channel
));
220 at91_adc_writel(st
, AT91_ADC_IER
, reg
->drdy_mask
);
223 at91_adc_writel(st
, AT91_ADC_IDR
, reg
->drdy_mask
);
225 at91_adc_writel(st
, reg
->trigger_register
,
228 for_each_set_bit(bit
, buffer
->scan_mask
,
230 struct iio_chan_spec
const *chan
= idev
->channels
+ bit
;
231 at91_adc_writel(st
, AT91_ADC_CHDR
,
232 AT91_ADC_CH(chan
->channel
));
240 static const struct iio_trigger_ops at91_adc_trigger_ops
= {
241 .owner
= THIS_MODULE
,
242 .set_trigger_state
= &at91_adc_configure_trigger
,
245 static struct iio_trigger
*at91_adc_allocate_trigger(struct iio_dev
*idev
,
246 struct at91_adc_trigger
*trigger
)
248 struct iio_trigger
*trig
;
251 trig
= iio_trigger_alloc("%s-dev%d-%s", idev
->name
,
252 idev
->id
, trigger
->name
);
256 trig
->dev
.parent
= idev
->dev
.parent
;
257 trig
->private_data
= idev
;
258 trig
->ops
= &at91_adc_trigger_ops
;
260 ret
= iio_trigger_register(trig
);
267 static int at91_adc_trigger_init(struct iio_dev
*idev
)
269 struct at91_adc_state
*st
= iio_priv(idev
);
272 st
->trig
= devm_kzalloc(&idev
->dev
,
273 st
->trigger_number
* sizeof(st
->trig
),
276 if (st
->trig
== NULL
) {
281 for (i
= 0; i
< st
->trigger_number
; i
++) {
282 if (st
->trigger_list
[i
].is_external
&& !(st
->use_external
))
285 st
->trig
[i
] = at91_adc_allocate_trigger(idev
,
286 st
->trigger_list
+ i
);
287 if (st
->trig
[i
] == NULL
) {
289 "Could not allocate trigger %d\n", i
);
298 for (i
--; i
>= 0; i
--) {
299 iio_trigger_unregister(st
->trig
[i
]);
300 iio_trigger_free(st
->trig
[i
]);
306 static void at91_adc_trigger_remove(struct iio_dev
*idev
)
308 struct at91_adc_state
*st
= iio_priv(idev
);
311 for (i
= 0; i
< st
->trigger_number
; i
++) {
312 iio_trigger_unregister(st
->trig
[i
]);
313 iio_trigger_free(st
->trig
[i
]);
317 static int at91_adc_buffer_init(struct iio_dev
*idev
)
319 return iio_triggered_buffer_setup(idev
, &iio_pollfunc_store_time
,
320 &at91_adc_trigger_handler
, NULL
);
323 static void at91_adc_buffer_remove(struct iio_dev
*idev
)
325 iio_triggered_buffer_cleanup(idev
);
328 static int at91_adc_read_raw(struct iio_dev
*idev
,
329 struct iio_chan_spec
const *chan
,
330 int *val
, int *val2
, long mask
)
332 struct at91_adc_state
*st
= iio_priv(idev
);
336 case IIO_CHAN_INFO_RAW
:
337 mutex_lock(&st
->lock
);
339 at91_adc_writel(st
, AT91_ADC_CHER
,
340 AT91_ADC_CH(chan
->channel
));
341 at91_adc_writel(st
, AT91_ADC_IER
, st
->registers
->drdy_mask
);
342 at91_adc_writel(st
, AT91_ADC_CR
, AT91_ADC_START
);
344 ret
= wait_event_interruptible_timeout(st
->wq_data_avail
,
346 msecs_to_jiffies(1000));
350 mutex_unlock(&st
->lock
);
354 *val
= st
->last_value
;
356 at91_adc_writel(st
, AT91_ADC_CHDR
,
357 AT91_ADC_CH(chan
->channel
));
358 at91_adc_writel(st
, AT91_ADC_IDR
, st
->registers
->drdy_mask
);
362 mutex_unlock(&st
->lock
);
365 case IIO_CHAN_INFO_SCALE
:
366 *val
= (st
->vref_mv
* 1000) >> chan
->scan_type
.realbits
;
368 return IIO_VAL_INT_PLUS_MICRO
;
375 static int at91_adc_probe_dt(struct at91_adc_state
*st
,
376 struct platform_device
*pdev
)
378 struct iio_dev
*idev
= iio_priv_to_dev(st
);
379 struct device_node
*node
= pdev
->dev
.of_node
;
380 struct device_node
*trig_node
;
387 st
->use_external
= of_property_read_bool(node
, "atmel,adc-use-external-triggers");
389 if (of_property_read_u32(node
, "atmel,adc-channels-used", &prop
)) {
390 dev_err(&idev
->dev
, "Missing adc-channels-used property in the DT.\n");
394 st
->channels_mask
= prop
;
396 if (of_property_read_u32(node
, "atmel,adc-num-channels", &prop
)) {
397 dev_err(&idev
->dev
, "Missing adc-num-channels property in the DT.\n");
401 st
->num_channels
= prop
;
403 if (of_property_read_u32(node
, "atmel,adc-startup-time", &prop
)) {
404 dev_err(&idev
->dev
, "Missing adc-startup-time property in the DT.\n");
408 st
->startup_time
= prop
;
411 if (of_property_read_u32(node
, "atmel,adc-vref", &prop
)) {
412 dev_err(&idev
->dev
, "Missing adc-vref property in the DT.\n");
418 st
->registers
= devm_kzalloc(&idev
->dev
,
419 sizeof(struct at91_adc_reg_desc
),
421 if (!st
->registers
) {
422 dev_err(&idev
->dev
, "Could not allocate register memory.\n");
427 if (of_property_read_u32(node
, "atmel,adc-channel-base", &prop
)) {
428 dev_err(&idev
->dev
, "Missing adc-channel-base property in the DT.\n");
432 st
->registers
->channel_base
= prop
;
434 if (of_property_read_u32(node
, "atmel,adc-drdy-mask", &prop
)) {
435 dev_err(&idev
->dev
, "Missing adc-drdy-mask property in the DT.\n");
439 st
->registers
->drdy_mask
= prop
;
441 if (of_property_read_u32(node
, "atmel,adc-status-register", &prop
)) {
442 dev_err(&idev
->dev
, "Missing adc-status-register property in the DT.\n");
446 st
->registers
->status_register
= prop
;
448 if (of_property_read_u32(node
, "atmel,adc-trigger-register", &prop
)) {
449 dev_err(&idev
->dev
, "Missing adc-trigger-register property in the DT.\n");
453 st
->registers
->trigger_register
= prop
;
455 st
->trigger_number
= of_get_child_count(node
);
456 st
->trigger_list
= devm_kzalloc(&idev
->dev
, st
->trigger_number
*
457 sizeof(struct at91_adc_trigger
),
459 if (!st
->trigger_list
) {
460 dev_err(&idev
->dev
, "Could not allocate trigger list memory.\n");
465 for_each_child_of_node(node
, trig_node
) {
466 struct at91_adc_trigger
*trig
= st
->trigger_list
+ i
;
469 if (of_property_read_string(trig_node
, "trigger-name", &name
)) {
470 dev_err(&idev
->dev
, "Missing trigger-name property in the DT.\n");
476 if (of_property_read_u32(trig_node
, "trigger-value", &prop
)) {
477 dev_err(&idev
->dev
, "Missing trigger-value property in the DT.\n");
482 trig
->is_external
= of_property_read_bool(trig_node
, "trigger-external");
492 static int at91_adc_probe_pdata(struct at91_adc_state
*st
,
493 struct platform_device
*pdev
)
495 struct at91_adc_data
*pdata
= pdev
->dev
.platform_data
;
500 st
->use_external
= pdata
->use_external_triggers
;
501 st
->vref_mv
= pdata
->vref
;
502 st
->channels_mask
= pdata
->channels_used
;
503 st
->num_channels
= pdata
->num_channels
;
504 st
->startup_time
= pdata
->startup_time
;
505 st
->trigger_number
= pdata
->trigger_number
;
506 st
->trigger_list
= pdata
->trigger_list
;
507 st
->registers
= pdata
->registers
;
512 static const struct iio_info at91_adc_info
= {
513 .driver_module
= THIS_MODULE
,
514 .read_raw
= &at91_adc_read_raw
,
517 static int at91_adc_probe(struct platform_device
*pdev
)
519 unsigned int prsc
, mstrclk
, ticks
, adc_clk
;
521 struct iio_dev
*idev
;
522 struct at91_adc_state
*st
;
523 struct resource
*res
;
525 idev
= iio_device_alloc(sizeof(struct at91_adc_state
));
533 if (pdev
->dev
.of_node
)
534 ret
= at91_adc_probe_dt(st
, pdev
);
536 ret
= at91_adc_probe_pdata(st
, pdev
);
539 dev_err(&pdev
->dev
, "No platform data available.\n");
541 goto error_free_device
;
544 platform_set_drvdata(pdev
, idev
);
546 idev
->dev
.parent
= &pdev
->dev
;
547 idev
->name
= dev_name(&pdev
->dev
);
548 idev
->modes
= INDIO_DIRECT_MODE
;
549 idev
->info
= &at91_adc_info
;
551 st
->irq
= platform_get_irq(pdev
, 0);
553 dev_err(&pdev
->dev
, "No IRQ ID is designated\n");
555 goto error_free_device
;
558 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
560 st
->reg_base
= devm_ioremap_resource(&pdev
->dev
, res
);
561 if (IS_ERR(st
->reg_base
)) {
562 ret
= PTR_ERR(st
->reg_base
);
563 goto error_free_device
;
567 * Disable all IRQs before setting up the handler
569 at91_adc_writel(st
, AT91_ADC_CR
, AT91_ADC_SWRST
);
570 at91_adc_writel(st
, AT91_ADC_IDR
, 0xFFFFFFFF);
571 ret
= request_irq(st
->irq
,
572 at91_adc_eoc_trigger
,
574 pdev
->dev
.driver
->name
,
577 dev_err(&pdev
->dev
, "Failed to allocate IRQ.\n");
578 goto error_free_device
;
581 st
->clk
= devm_clk_get(&pdev
->dev
, "adc_clk");
582 if (IS_ERR(st
->clk
)) {
583 dev_err(&pdev
->dev
, "Failed to get the clock.\n");
584 ret
= PTR_ERR(st
->clk
);
588 ret
= clk_prepare_enable(st
->clk
);
591 "Could not prepare or enable the clock.\n");
595 st
->adc_clk
= devm_clk_get(&pdev
->dev
, "adc_op_clk");
596 if (IS_ERR(st
->adc_clk
)) {
597 dev_err(&pdev
->dev
, "Failed to get the ADC clock.\n");
598 ret
= PTR_ERR(st
->adc_clk
);
599 goto error_disable_clk
;
602 ret
= clk_prepare_enable(st
->adc_clk
);
605 "Could not prepare or enable the ADC clock.\n");
606 goto error_disable_clk
;
610 * Prescaler rate computation using the formula from the Atmel's
611 * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
612 * specified by the electrical characteristics of the board.
614 mstrclk
= clk_get_rate(st
->clk
);
615 adc_clk
= clk_get_rate(st
->adc_clk
);
616 prsc
= (mstrclk
/ (2 * adc_clk
)) - 1;
618 if (!st
->startup_time
) {
619 dev_err(&pdev
->dev
, "No startup time available.\n");
621 goto error_disable_adc_clk
;
625 * Number of ticks needed to cover the startup time of the ADC as
626 * defined in the electrical characteristics of the board, divided by 8.
627 * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
629 ticks
= round_up((st
->startup_time
* adc_clk
/
630 1000000) - 1, 8) / 8;
631 at91_adc_writel(st
, AT91_ADC_MR
,
632 (AT91_ADC_PRESCAL_(prsc
) & AT91_ADC_PRESCAL
) |
633 (AT91_ADC_STARTUP_(ticks
) & AT91_ADC_STARTUP
));
635 /* Setup the ADC channels available on the board */
636 ret
= at91_adc_channel_init(idev
);
638 dev_err(&pdev
->dev
, "Couldn't initialize the channels.\n");
639 goto error_disable_adc_clk
;
642 init_waitqueue_head(&st
->wq_data_avail
);
643 mutex_init(&st
->lock
);
645 ret
= at91_adc_buffer_init(idev
);
647 dev_err(&pdev
->dev
, "Couldn't initialize the buffer.\n");
648 goto error_disable_adc_clk
;
651 ret
= at91_adc_trigger_init(idev
);
653 dev_err(&pdev
->dev
, "Couldn't setup the triggers.\n");
654 goto error_unregister_buffer
;
657 ret
= iio_device_register(idev
);
659 dev_err(&pdev
->dev
, "Couldn't register the device.\n");
660 goto error_remove_triggers
;
665 error_remove_triggers
:
666 at91_adc_trigger_remove(idev
);
667 error_unregister_buffer
:
668 at91_adc_buffer_remove(idev
);
669 error_disable_adc_clk
:
670 clk_disable_unprepare(st
->adc_clk
);
672 clk_disable_unprepare(st
->clk
);
674 free_irq(st
->irq
, idev
);
676 iio_device_free(idev
);
681 static int at91_adc_remove(struct platform_device
*pdev
)
683 struct iio_dev
*idev
= platform_get_drvdata(pdev
);
684 struct at91_adc_state
*st
= iio_priv(idev
);
686 iio_device_unregister(idev
);
687 at91_adc_trigger_remove(idev
);
688 at91_adc_buffer_remove(idev
);
689 clk_disable_unprepare(st
->adc_clk
);
690 clk_disable_unprepare(st
->clk
);
691 free_irq(st
->irq
, idev
);
692 iio_device_free(idev
);
697 static const struct of_device_id at91_adc_dt_ids
[] = {
698 { .compatible
= "atmel,at91sam9260-adc" },
701 MODULE_DEVICE_TABLE(of
, at91_adc_dt_ids
);
703 static struct platform_driver at91_adc_driver
= {
704 .probe
= at91_adc_probe
,
705 .remove
= at91_adc_remove
,
708 .of_match_table
= of_match_ptr(at91_adc_dt_ids
),
712 module_platform_driver(at91_adc_driver
);
714 MODULE_LICENSE("GPL");
715 MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
716 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");