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
;
57 struct iio_trigger
**trig
;
58 struct at91_adc_trigger
*trigger_list
;
62 u32 res
; /* resolution used for convertions */
63 bool low_res
; /* the resolution corresponds to the lowest one */
64 wait_queue_head_t wq_data_avail
;
67 static irqreturn_t
at91_adc_trigger_handler(int irq
, void *p
)
69 struct iio_poll_func
*pf
= p
;
70 struct iio_dev
*idev
= pf
->indio_dev
;
71 struct at91_adc_state
*st
= iio_priv(idev
);
74 for (i
= 0; i
< idev
->masklength
; i
++) {
75 if (!test_bit(i
, idev
->active_scan_mask
))
77 st
->buffer
[j
] = at91_adc_readl(st
, AT91_ADC_CHAN(st
, i
));
81 if (idev
->scan_timestamp
) {
82 s64
*timestamp
= (s64
*)((u8
*)st
->buffer
+
83 ALIGN(j
, sizeof(s64
)));
84 *timestamp
= pf
->timestamp
;
87 iio_push_to_buffers(idev
, (u8
*)st
->buffer
);
89 iio_trigger_notify_done(idev
->trig
);
91 /* Needed to ACK the DRDY interruption */
92 at91_adc_readl(st
, AT91_ADC_LCDR
);
99 static irqreturn_t
at91_adc_eoc_trigger(int irq
, void *private)
101 struct iio_dev
*idev
= private;
102 struct at91_adc_state
*st
= iio_priv(idev
);
103 u32 status
= at91_adc_readl(st
, st
->registers
->status_register
);
105 if (!(status
& st
->registers
->drdy_mask
))
108 if (iio_buffer_enabled(idev
)) {
109 disable_irq_nosync(irq
);
110 iio_trigger_poll(idev
->trig
, iio_get_time_ns());
112 st
->last_value
= at91_adc_readl(st
, AT91_ADC_LCDR
);
114 wake_up_interruptible(&st
->wq_data_avail
);
120 static int at91_adc_channel_init(struct iio_dev
*idev
)
122 struct at91_adc_state
*st
= iio_priv(idev
);
123 struct iio_chan_spec
*chan_array
, *timestamp
;
126 idev
->num_channels
= bitmap_weight(&st
->channels_mask
,
127 st
->num_channels
) + 1;
129 chan_array
= devm_kzalloc(&idev
->dev
,
130 ((idev
->num_channels
+ 1) *
131 sizeof(struct iio_chan_spec
)),
137 for_each_set_bit(bit
, &st
->channels_mask
, st
->num_channels
) {
138 struct iio_chan_spec
*chan
= chan_array
+ idx
;
140 chan
->type
= IIO_VOLTAGE
;
143 chan
->scan_index
= idx
;
144 chan
->scan_type
.sign
= 'u';
145 chan
->scan_type
.realbits
= st
->res
;
146 chan
->scan_type
.storagebits
= 16;
147 chan
->info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_SCALE
);
148 chan
->info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
);
151 timestamp
= chan_array
+ idx
;
153 timestamp
->type
= IIO_TIMESTAMP
;
154 timestamp
->channel
= -1;
155 timestamp
->scan_index
= idx
;
156 timestamp
->scan_type
.sign
= 's';
157 timestamp
->scan_type
.realbits
= 64;
158 timestamp
->scan_type
.storagebits
= 64;
160 idev
->channels
= chan_array
;
161 return idev
->num_channels
;
164 static u8
at91_adc_get_trigger_value_by_name(struct iio_dev
*idev
,
165 struct at91_adc_trigger
*triggers
,
166 const char *trigger_name
)
168 struct at91_adc_state
*st
= iio_priv(idev
);
172 for (i
= 0; i
< st
->trigger_number
; i
++) {
173 char *name
= kasprintf(GFP_KERNEL
,
181 if (strcmp(trigger_name
, name
) == 0) {
182 value
= triggers
[i
].value
;
193 static int at91_adc_configure_trigger(struct iio_trigger
*trig
, bool state
)
195 struct iio_dev
*idev
= iio_trigger_get_drvdata(trig
);
196 struct at91_adc_state
*st
= iio_priv(idev
);
197 struct iio_buffer
*buffer
= idev
->buffer
;
198 struct at91_adc_reg_desc
*reg
= st
->registers
;
199 u32 status
= at91_adc_readl(st
, reg
->trigger_register
);
203 value
= at91_adc_get_trigger_value_by_name(idev
,
210 st
->buffer
= kmalloc(idev
->scan_bytes
, GFP_KERNEL
);
211 if (st
->buffer
== NULL
)
214 at91_adc_writel(st
, reg
->trigger_register
,
217 for_each_set_bit(bit
, buffer
->scan_mask
,
219 struct iio_chan_spec
const *chan
= idev
->channels
+ bit
;
220 at91_adc_writel(st
, AT91_ADC_CHER
,
221 AT91_ADC_CH(chan
->channel
));
224 at91_adc_writel(st
, AT91_ADC_IER
, reg
->drdy_mask
);
227 at91_adc_writel(st
, AT91_ADC_IDR
, reg
->drdy_mask
);
229 at91_adc_writel(st
, reg
->trigger_register
,
232 for_each_set_bit(bit
, buffer
->scan_mask
,
234 struct iio_chan_spec
const *chan
= idev
->channels
+ bit
;
235 at91_adc_writel(st
, AT91_ADC_CHDR
,
236 AT91_ADC_CH(chan
->channel
));
244 static const struct iio_trigger_ops at91_adc_trigger_ops
= {
245 .owner
= THIS_MODULE
,
246 .set_trigger_state
= &at91_adc_configure_trigger
,
249 static struct iio_trigger
*at91_adc_allocate_trigger(struct iio_dev
*idev
,
250 struct at91_adc_trigger
*trigger
)
252 struct iio_trigger
*trig
;
255 trig
= iio_trigger_alloc("%s-dev%d-%s", idev
->name
,
256 idev
->id
, trigger
->name
);
260 trig
->dev
.parent
= idev
->dev
.parent
;
261 iio_trigger_set_drvdata(trig
, idev
);
262 trig
->ops
= &at91_adc_trigger_ops
;
264 ret
= iio_trigger_register(trig
);
271 static int at91_adc_trigger_init(struct iio_dev
*idev
)
273 struct at91_adc_state
*st
= iio_priv(idev
);
276 st
->trig
= devm_kzalloc(&idev
->dev
,
277 st
->trigger_number
* sizeof(st
->trig
),
280 if (st
->trig
== NULL
) {
285 for (i
= 0; i
< st
->trigger_number
; i
++) {
286 if (st
->trigger_list
[i
].is_external
&& !(st
->use_external
))
289 st
->trig
[i
] = at91_adc_allocate_trigger(idev
,
290 st
->trigger_list
+ i
);
291 if (st
->trig
[i
] == NULL
) {
293 "Could not allocate trigger %d\n", i
);
302 for (i
--; i
>= 0; i
--) {
303 iio_trigger_unregister(st
->trig
[i
]);
304 iio_trigger_free(st
->trig
[i
]);
310 static void at91_adc_trigger_remove(struct iio_dev
*idev
)
312 struct at91_adc_state
*st
= iio_priv(idev
);
315 for (i
= 0; i
< st
->trigger_number
; i
++) {
316 iio_trigger_unregister(st
->trig
[i
]);
317 iio_trigger_free(st
->trig
[i
]);
321 static int at91_adc_buffer_init(struct iio_dev
*idev
)
323 return iio_triggered_buffer_setup(idev
, &iio_pollfunc_store_time
,
324 &at91_adc_trigger_handler
, NULL
);
327 static void at91_adc_buffer_remove(struct iio_dev
*idev
)
329 iio_triggered_buffer_cleanup(idev
);
332 static int at91_adc_read_raw(struct iio_dev
*idev
,
333 struct iio_chan_spec
const *chan
,
334 int *val
, int *val2
, long mask
)
336 struct at91_adc_state
*st
= iio_priv(idev
);
340 case IIO_CHAN_INFO_RAW
:
341 mutex_lock(&st
->lock
);
343 at91_adc_writel(st
, AT91_ADC_CHER
,
344 AT91_ADC_CH(chan
->channel
));
345 at91_adc_writel(st
, AT91_ADC_IER
, st
->registers
->drdy_mask
);
346 at91_adc_writel(st
, AT91_ADC_CR
, AT91_ADC_START
);
348 ret
= wait_event_interruptible_timeout(st
->wq_data_avail
,
350 msecs_to_jiffies(1000));
354 mutex_unlock(&st
->lock
);
358 *val
= st
->last_value
;
360 at91_adc_writel(st
, AT91_ADC_CHDR
,
361 AT91_ADC_CH(chan
->channel
));
362 at91_adc_writel(st
, AT91_ADC_IDR
, st
->registers
->drdy_mask
);
366 mutex_unlock(&st
->lock
);
369 case IIO_CHAN_INFO_SCALE
:
370 *val
= (st
->vref_mv
* 1000) >> chan
->scan_type
.realbits
;
372 return IIO_VAL_INT_PLUS_MICRO
;
379 static int at91_adc_of_get_resolution(struct at91_adc_state
*st
,
380 struct platform_device
*pdev
)
382 struct iio_dev
*idev
= iio_priv_to_dev(st
);
383 struct device_node
*np
= pdev
->dev
.of_node
;
384 int count
, i
, ret
= 0;
388 count
= of_property_count_strings(np
, "atmel,adc-res-names");
390 dev_err(&idev
->dev
, "You must specified at least two resolution names for "
391 "adc-res-names property in the DT\n");
395 resolutions
= kmalloc(count
* sizeof(*resolutions
), GFP_KERNEL
);
399 if (of_property_read_u32_array(np
, "atmel,adc-res", resolutions
, count
)) {
400 dev_err(&idev
->dev
, "Missing adc-res property in the DT.\n");
405 if (of_property_read_string(np
, "atmel,adc-use-res", (const char **)&res_name
))
406 res_name
= "highres";
408 for (i
= 0; i
< count
; i
++) {
409 if (of_property_read_string_index(np
, "atmel,adc-res-names", i
, (const char **)&s
))
412 if (strcmp(res_name
, s
))
415 st
->res
= resolutions
[i
];
416 if (!strcmp(res_name
, "lowres"))
421 dev_info(&idev
->dev
, "Resolution used: %u bits\n", st
->res
);
425 dev_err(&idev
->dev
, "There is no resolution for %s\n", res_name
);
432 static int at91_adc_probe_dt(struct at91_adc_state
*st
,
433 struct platform_device
*pdev
)
435 struct iio_dev
*idev
= iio_priv_to_dev(st
);
436 struct device_node
*node
= pdev
->dev
.of_node
;
437 struct device_node
*trig_node
;
444 st
->use_external
= of_property_read_bool(node
, "atmel,adc-use-external-triggers");
446 if (of_property_read_u32(node
, "atmel,adc-channels-used", &prop
)) {
447 dev_err(&idev
->dev
, "Missing adc-channels-used property in the DT.\n");
451 st
->channels_mask
= prop
;
453 if (of_property_read_u32(node
, "atmel,adc-num-channels", &prop
)) {
454 dev_err(&idev
->dev
, "Missing adc-num-channels property in the DT.\n");
458 st
->num_channels
= prop
;
460 st
->sleep_mode
= of_property_read_bool(node
, "atmel,adc-sleep-mode");
462 if (of_property_read_u32(node
, "atmel,adc-startup-time", &prop
)) {
463 dev_err(&idev
->dev
, "Missing adc-startup-time property in the DT.\n");
467 st
->startup_time
= prop
;
470 of_property_read_u32(node
, "atmel,adc-sample-hold-time", &prop
);
471 st
->sample_hold_time
= prop
;
473 if (of_property_read_u32(node
, "atmel,adc-vref", &prop
)) {
474 dev_err(&idev
->dev
, "Missing adc-vref property in the DT.\n");
480 ret
= at91_adc_of_get_resolution(st
, pdev
);
484 st
->registers
= devm_kzalloc(&idev
->dev
,
485 sizeof(struct at91_adc_reg_desc
),
487 if (!st
->registers
) {
488 dev_err(&idev
->dev
, "Could not allocate register memory.\n");
493 if (of_property_read_u32(node
, "atmel,adc-channel-base", &prop
)) {
494 dev_err(&idev
->dev
, "Missing adc-channel-base property in the DT.\n");
498 st
->registers
->channel_base
= prop
;
500 if (of_property_read_u32(node
, "atmel,adc-drdy-mask", &prop
)) {
501 dev_err(&idev
->dev
, "Missing adc-drdy-mask property in the DT.\n");
505 st
->registers
->drdy_mask
= prop
;
507 if (of_property_read_u32(node
, "atmel,adc-status-register", &prop
)) {
508 dev_err(&idev
->dev
, "Missing adc-status-register property in the DT.\n");
512 st
->registers
->status_register
= prop
;
514 if (of_property_read_u32(node
, "atmel,adc-trigger-register", &prop
)) {
515 dev_err(&idev
->dev
, "Missing adc-trigger-register property in the DT.\n");
519 st
->registers
->trigger_register
= prop
;
521 st
->trigger_number
= of_get_child_count(node
);
522 st
->trigger_list
= devm_kzalloc(&idev
->dev
, st
->trigger_number
*
523 sizeof(struct at91_adc_trigger
),
525 if (!st
->trigger_list
) {
526 dev_err(&idev
->dev
, "Could not allocate trigger list memory.\n");
531 for_each_child_of_node(node
, trig_node
) {
532 struct at91_adc_trigger
*trig
= st
->trigger_list
+ i
;
535 if (of_property_read_string(trig_node
, "trigger-name", &name
)) {
536 dev_err(&idev
->dev
, "Missing trigger-name property in the DT.\n");
542 if (of_property_read_u32(trig_node
, "trigger-value", &prop
)) {
543 dev_err(&idev
->dev
, "Missing trigger-value property in the DT.\n");
548 trig
->is_external
= of_property_read_bool(trig_node
, "trigger-external");
558 static int at91_adc_probe_pdata(struct at91_adc_state
*st
,
559 struct platform_device
*pdev
)
561 struct at91_adc_data
*pdata
= pdev
->dev
.platform_data
;
566 st
->use_external
= pdata
->use_external_triggers
;
567 st
->vref_mv
= pdata
->vref
;
568 st
->channels_mask
= pdata
->channels_used
;
569 st
->num_channels
= pdata
->num_channels
;
570 st
->startup_time
= pdata
->startup_time
;
571 st
->trigger_number
= pdata
->trigger_number
;
572 st
->trigger_list
= pdata
->trigger_list
;
573 st
->registers
= pdata
->registers
;
578 static const struct iio_info at91_adc_info
= {
579 .driver_module
= THIS_MODULE
,
580 .read_raw
= &at91_adc_read_raw
,
583 static int at91_adc_probe(struct platform_device
*pdev
)
585 unsigned int prsc
, mstrclk
, ticks
, adc_clk
, shtim
;
587 struct iio_dev
*idev
;
588 struct at91_adc_state
*st
;
589 struct resource
*res
;
592 idev
= iio_device_alloc(sizeof(struct at91_adc_state
));
600 if (pdev
->dev
.of_node
)
601 ret
= at91_adc_probe_dt(st
, pdev
);
603 ret
= at91_adc_probe_pdata(st
, pdev
);
606 dev_err(&pdev
->dev
, "No platform data available.\n");
608 goto error_free_device
;
611 platform_set_drvdata(pdev
, idev
);
613 idev
->dev
.parent
= &pdev
->dev
;
614 idev
->name
= dev_name(&pdev
->dev
);
615 idev
->modes
= INDIO_DIRECT_MODE
;
616 idev
->info
= &at91_adc_info
;
618 st
->irq
= platform_get_irq(pdev
, 0);
620 dev_err(&pdev
->dev
, "No IRQ ID is designated\n");
622 goto error_free_device
;
625 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
627 st
->reg_base
= devm_ioremap_resource(&pdev
->dev
, res
);
628 if (IS_ERR(st
->reg_base
)) {
629 ret
= PTR_ERR(st
->reg_base
);
630 goto error_free_device
;
634 * Disable all IRQs before setting up the handler
636 at91_adc_writel(st
, AT91_ADC_CR
, AT91_ADC_SWRST
);
637 at91_adc_writel(st
, AT91_ADC_IDR
, 0xFFFFFFFF);
638 ret
= request_irq(st
->irq
,
639 at91_adc_eoc_trigger
,
641 pdev
->dev
.driver
->name
,
644 dev_err(&pdev
->dev
, "Failed to allocate IRQ.\n");
645 goto error_free_device
;
648 st
->clk
= devm_clk_get(&pdev
->dev
, "adc_clk");
649 if (IS_ERR(st
->clk
)) {
650 dev_err(&pdev
->dev
, "Failed to get the clock.\n");
651 ret
= PTR_ERR(st
->clk
);
655 ret
= clk_prepare_enable(st
->clk
);
658 "Could not prepare or enable the clock.\n");
662 st
->adc_clk
= devm_clk_get(&pdev
->dev
, "adc_op_clk");
663 if (IS_ERR(st
->adc_clk
)) {
664 dev_err(&pdev
->dev
, "Failed to get the ADC clock.\n");
665 ret
= PTR_ERR(st
->adc_clk
);
666 goto error_disable_clk
;
669 ret
= clk_prepare_enable(st
->adc_clk
);
672 "Could not prepare or enable the ADC clock.\n");
673 goto error_disable_clk
;
677 * Prescaler rate computation using the formula from the Atmel's
678 * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
679 * specified by the electrical characteristics of the board.
681 mstrclk
= clk_get_rate(st
->clk
);
682 adc_clk
= clk_get_rate(st
->adc_clk
);
683 prsc
= (mstrclk
/ (2 * adc_clk
)) - 1;
685 if (!st
->startup_time
) {
686 dev_err(&pdev
->dev
, "No startup time available.\n");
688 goto error_disable_adc_clk
;
692 * Number of ticks needed to cover the startup time of the ADC as
693 * defined in the electrical characteristics of the board, divided by 8.
694 * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
696 ticks
= round_up((st
->startup_time
* adc_clk
/
697 1000000) - 1, 8) / 8;
699 * a minimal Sample and Hold Time is necessary for the ADC to guarantee
700 * the best converted final value between two channels selection
701 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
703 shtim
= round_up((st
->sample_hold_time
* adc_clk
/
706 reg
= AT91_ADC_PRESCAL_(prsc
) & AT91_ADC_PRESCAL
;
707 reg
|= AT91_ADC_STARTUP_(ticks
) & AT91_ADC_STARTUP
;
709 reg
|= AT91_ADC_LOWRES
;
711 reg
|= AT91_ADC_SLEEP
;
712 reg
|= AT91_ADC_SHTIM_(shtim
) & AT91_ADC_SHTIM
;
713 at91_adc_writel(st
, AT91_ADC_MR
, reg
);
715 /* Setup the ADC channels available on the board */
716 ret
= at91_adc_channel_init(idev
);
718 dev_err(&pdev
->dev
, "Couldn't initialize the channels.\n");
719 goto error_disable_adc_clk
;
722 init_waitqueue_head(&st
->wq_data_avail
);
723 mutex_init(&st
->lock
);
725 ret
= at91_adc_buffer_init(idev
);
727 dev_err(&pdev
->dev
, "Couldn't initialize the buffer.\n");
728 goto error_disable_adc_clk
;
731 ret
= at91_adc_trigger_init(idev
);
733 dev_err(&pdev
->dev
, "Couldn't setup the triggers.\n");
734 goto error_unregister_buffer
;
737 ret
= iio_device_register(idev
);
739 dev_err(&pdev
->dev
, "Couldn't register the device.\n");
740 goto error_remove_triggers
;
745 error_remove_triggers
:
746 at91_adc_trigger_remove(idev
);
747 error_unregister_buffer
:
748 at91_adc_buffer_remove(idev
);
749 error_disable_adc_clk
:
750 clk_disable_unprepare(st
->adc_clk
);
752 clk_disable_unprepare(st
->clk
);
754 free_irq(st
->irq
, idev
);
756 iio_device_free(idev
);
761 static int at91_adc_remove(struct platform_device
*pdev
)
763 struct iio_dev
*idev
= platform_get_drvdata(pdev
);
764 struct at91_adc_state
*st
= iio_priv(idev
);
766 iio_device_unregister(idev
);
767 at91_adc_trigger_remove(idev
);
768 at91_adc_buffer_remove(idev
);
769 clk_disable_unprepare(st
->adc_clk
);
770 clk_disable_unprepare(st
->clk
);
771 free_irq(st
->irq
, idev
);
772 iio_device_free(idev
);
777 static const struct of_device_id at91_adc_dt_ids
[] = {
778 { .compatible
= "atmel,at91sam9260-adc" },
781 MODULE_DEVICE_TABLE(of
, at91_adc_dt_ids
);
783 static struct platform_driver at91_adc_driver
= {
784 .probe
= at91_adc_probe
,
785 .remove
= at91_adc_remove
,
788 .of_match_table
= of_match_ptr(at91_adc_dt_ids
),
792 module_platform_driver(at91_adc_driver
);
794 MODULE_LICENSE("GPL");
795 MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
796 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");