ARM: AT91: IIO: Add AT91 ADC driver.
Add the ADC driver for Atmel's AT91SAM9G20-EK, AT91SAM9M10G45-EK and AT91SAM9X5 family boards. It has support for both software and hardware triggers. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Maxime Ripard
Greg Kroah-Hartman
parent
aaeb6dfff0
commit
0e589d5fb3
5 changed files with 695 additions and 0 deletions
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@ -48,6 +48,7 @@ config IIO_CONSUMERS_PER_TRIGGER
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This value controls the maximum number of consumers that a
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given trigger may handle. Default is 2.
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source "drivers/iio/adc/Kconfig"
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source "drivers/iio/amplifiers/Kconfig"
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endif # IIO
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@ -9,4 +9,5 @@ industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
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obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
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obj-y += adc/
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obj-y += amplifiers/
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16
drivers/iio/adc/Kconfig
Normal file
16
drivers/iio/adc/Kconfig
Normal file
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@ -0,0 +1,16 @@
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#
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# ADC drivers
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#
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menu "Analog to digital converters"
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config AT91_ADC
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tristate "Atmel AT91 ADC"
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depends on ARCH_AT91
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select IIO_BUFFER
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select IIO_KFIFO_BUF
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select IIO_TRIGGER
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select SYSFS
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help
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Say yes here to build support for Atmel AT91 ADC.
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endmenu
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5
drivers/iio/adc/Makefile
Normal file
5
drivers/iio/adc/Makefile
Normal file
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@ -0,0 +1,5 @@
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#
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# Makefile for IIO ADC drivers
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#
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obj-$(CONFIG_AT91_ADC) += at91_adc.o
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672
drivers/iio/adc/at91_adc.c
Normal file
672
drivers/iio/adc/at91_adc.c
Normal file
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@ -0,0 +1,672 @@
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/*
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* Driver for the ADC present in the Atmel AT91 evaluation boards.
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*
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* Copyright 2011 Free Electrons
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*
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* Licensed under the GPLv2 or later.
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*/
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#include <linux/bitmap.h>
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/interrupt.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/wait.h>
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#include <linux/platform_data/at91_adc.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/kfifo_buf.h>
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#include <linux/iio/trigger.h>
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#include <linux/iio/trigger_consumer.h>
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#include <mach/at91_adc.h>
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#define AT91_ADC_CHAN(st, ch) \
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(st->registers->channel_base + (ch * 4))
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#define at91_adc_readl(st, reg) \
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(readl_relaxed(st->reg_base + reg))
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#define at91_adc_writel(st, reg, val) \
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(writel_relaxed(val, st->reg_base + reg))
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struct at91_adc_state {
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struct clk *adc_clk;
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u16 *buffer;
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unsigned long channels_mask;
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struct clk *clk;
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bool done;
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int irq;
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bool irq_enabled;
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u16 last_value;
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struct mutex lock;
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u8 num_channels;
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void __iomem *reg_base;
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struct at91_adc_reg_desc *registers;
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u8 startup_time;
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struct iio_trigger **trig;
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struct at91_adc_trigger *trigger_list;
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u32 trigger_number;
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bool use_external;
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u32 vref_mv;
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wait_queue_head_t wq_data_avail;
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};
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static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
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{
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struct iio_poll_func *pf = p;
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struct iio_dev *idev = pf->indio_dev;
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struct at91_adc_state *st = iio_priv(idev);
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struct iio_buffer *buffer = idev->buffer;
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int i, j = 0;
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for (i = 0; i < idev->masklength; i++) {
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if (!test_bit(i, idev->active_scan_mask))
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continue;
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st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
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j++;
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}
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if (idev->scan_timestamp) {
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s64 *timestamp = (s64 *)((u8 *)st->buffer +
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ALIGN(j, sizeof(s64)));
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*timestamp = pf->timestamp;
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}
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buffer->access->store_to(buffer, (u8 *)st->buffer, pf->timestamp);
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iio_trigger_notify_done(idev->trig);
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st->irq_enabled = true;
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/* Needed to ACK the DRDY interruption */
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at91_adc_readl(st, AT91_ADC_LCDR);
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enable_irq(st->irq);
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return IRQ_HANDLED;
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}
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static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
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{
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struct iio_dev *idev = private;
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struct at91_adc_state *st = iio_priv(idev);
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u32 status = at91_adc_readl(st, st->registers->status_register);
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if (!(status & st->registers->drdy_mask))
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return IRQ_HANDLED;
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if (iio_buffer_enabled(idev)) {
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disable_irq_nosync(irq);
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st->irq_enabled = false;
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iio_trigger_poll(idev->trig, iio_get_time_ns());
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} else {
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st->last_value = at91_adc_readl(st, AT91_ADC_LCDR);
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st->done = true;
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wake_up_interruptible(&st->wq_data_avail);
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}
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return IRQ_HANDLED;
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}
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static int at91_adc_channel_init(struct iio_dev *idev)
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{
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struct at91_adc_state *st = iio_priv(idev);
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struct iio_chan_spec *chan_array, *timestamp;
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int bit, idx = 0;
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idev->num_channels = bitmap_weight(&st->channels_mask,
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st->num_channels) + 1;
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chan_array = devm_kzalloc(&idev->dev,
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((idev->num_channels + 1) *
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sizeof(struct iio_chan_spec)),
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GFP_KERNEL);
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if (!chan_array)
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return -ENOMEM;
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for_each_set_bit(bit, &st->channels_mask, st->num_channels) {
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struct iio_chan_spec *chan = chan_array + idx;
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chan->type = IIO_VOLTAGE;
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chan->indexed = 1;
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chan->channel = bit;
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chan->scan_index = idx;
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chan->scan_type.sign = 'u';
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chan->scan_type.realbits = 10;
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chan->scan_type.storagebits = 16;
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chan->info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT |
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IIO_CHAN_INFO_RAW_SEPARATE_BIT;
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idx++;
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}
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timestamp = chan_array + idx;
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timestamp->type = IIO_TIMESTAMP;
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timestamp->channel = -1;
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timestamp->scan_index = idx;
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timestamp->scan_type.sign = 's';
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timestamp->scan_type.realbits = 64;
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timestamp->scan_type.storagebits = 64;
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idev->channels = chan_array;
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return idev->num_channels;
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}
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static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
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struct at91_adc_trigger *triggers,
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const char *trigger_name)
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{
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struct at91_adc_state *st = iio_priv(idev);
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u8 value = 0;
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int i;
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for (i = 0; i < st->trigger_number; i++) {
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char *name = kasprintf(GFP_KERNEL,
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"%s-dev%d-%s",
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idev->name,
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idev->id,
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triggers[i].name);
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if (!name)
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return -ENOMEM;
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if (strcmp(trigger_name, name) == 0) {
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value = triggers[i].value;
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kfree(name);
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break;
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}
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kfree(name);
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}
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return value;
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}
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static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
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{
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struct iio_dev *idev = trig->private_data;
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struct at91_adc_state *st = iio_priv(idev);
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struct iio_buffer *buffer = idev->buffer;
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struct at91_adc_reg_desc *reg = st->registers;
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u32 status = at91_adc_readl(st, reg->trigger_register);
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u8 value;
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u8 bit;
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value = at91_adc_get_trigger_value_by_name(idev,
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st->trigger_list,
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idev->trig->name);
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if (value == 0)
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return -EINVAL;
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if (state) {
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st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);
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if (st->buffer == NULL)
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return -ENOMEM;
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at91_adc_writel(st, reg->trigger_register,
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status | value);
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for_each_set_bit(bit, buffer->scan_mask,
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st->num_channels) {
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struct iio_chan_spec const *chan = idev->channels + bit;
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at91_adc_writel(st, AT91_ADC_CHER,
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AT91_ADC_CH(chan->channel));
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}
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at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask);
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} else {
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at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask);
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at91_adc_writel(st, reg->trigger_register,
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status & ~value);
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for_each_set_bit(bit, buffer->scan_mask,
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st->num_channels) {
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struct iio_chan_spec const *chan = idev->channels + bit;
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at91_adc_writel(st, AT91_ADC_CHDR,
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AT91_ADC_CH(chan->channel));
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}
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kfree(st->buffer);
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}
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return 0;
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}
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static const struct iio_trigger_ops at91_adc_trigger_ops = {
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.owner = THIS_MODULE,
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.set_trigger_state = &at91_adc_configure_trigger,
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};
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static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev,
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struct at91_adc_trigger *trigger)
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{
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struct iio_trigger *trig;
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int ret;
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trig = iio_trigger_alloc("%s-dev%d-%s", idev->name,
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idev->id, trigger->name);
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if (trig == NULL)
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return NULL;
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trig->dev.parent = idev->dev.parent;
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trig->private_data = idev;
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trig->ops = &at91_adc_trigger_ops;
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ret = iio_trigger_register(trig);
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if (ret)
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return NULL;
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return trig;
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}
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static int at91_adc_trigger_init(struct iio_dev *idev)
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{
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struct at91_adc_state *st = iio_priv(idev);
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int i, ret;
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st->trig = devm_kzalloc(&idev->dev,
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st->trigger_number * sizeof(st->trig),
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GFP_KERNEL);
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if (st->trig == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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for (i = 0; i < st->trigger_number; i++) {
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if (st->trigger_list[i].is_external && !(st->use_external))
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continue;
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st->trig[i] = at91_adc_allocate_trigger(idev,
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st->trigger_list + i);
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if (st->trig[i] == NULL) {
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dev_err(&idev->dev,
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"Could not allocate trigger %d\n", i);
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ret = -ENOMEM;
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goto error_trigger;
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}
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}
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return 0;
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error_trigger:
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for (i--; i >= 0; i--) {
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iio_trigger_unregister(st->trig[i]);
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iio_trigger_free(st->trig[i]);
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}
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error_ret:
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return ret;
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}
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static void at91_adc_trigger_remove(struct iio_dev *idev)
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{
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struct at91_adc_state *st = iio_priv(idev);
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int i;
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for (i = 0; i < st->trigger_number; i++) {
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iio_trigger_unregister(st->trig[i]);
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iio_trigger_free(st->trig[i]);
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}
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}
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static const struct iio_buffer_setup_ops at91_adc_buffer_ops = {
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.preenable = &iio_sw_buffer_preenable,
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.postenable = &iio_triggered_buffer_postenable,
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.predisable = &iio_triggered_buffer_predisable,
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};
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static int at91_adc_buffer_init(struct iio_dev *idev)
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{
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int ret;
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idev->buffer = iio_kfifo_allocate(idev);
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if (!idev->buffer) {
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ret = -ENOMEM;
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goto error_ret;
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}
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idev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
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&at91_adc_trigger_handler,
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IRQF_ONESHOT,
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idev,
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"%s-consumer%d",
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idev->name,
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idev->id);
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if (idev->pollfunc == NULL) {
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ret = -ENOMEM;
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goto error_pollfunc;
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}
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idev->setup_ops = &at91_adc_buffer_ops;
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idev->modes |= INDIO_BUFFER_TRIGGERED;
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ret = iio_buffer_register(idev,
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idev->channels,
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idev->num_channels);
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if (ret)
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goto error_register;
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return 0;
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error_register:
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iio_dealloc_pollfunc(idev->pollfunc);
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error_pollfunc:
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iio_kfifo_free(idev->buffer);
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error_ret:
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return ret;
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}
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static void at91_adc_buffer_remove(struct iio_dev *idev)
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{
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iio_buffer_unregister(idev);
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iio_dealloc_pollfunc(idev->pollfunc);
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iio_kfifo_free(idev->buffer);
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}
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static int at91_adc_read_raw(struct iio_dev *idev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct at91_adc_state *st = iio_priv(idev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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mutex_lock(&st->lock);
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at91_adc_writel(st, AT91_ADC_CHER,
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AT91_ADC_CH(chan->channel));
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at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask);
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at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START);
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ret = wait_event_interruptible_timeout(st->wq_data_avail,
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st->done,
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msecs_to_jiffies(1000));
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if (ret == 0)
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return -ETIMEDOUT;
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else if (ret < 0)
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return ret;
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*val = st->last_value;
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at91_adc_writel(st, AT91_ADC_CHDR,
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AT91_ADC_CH(chan->channel));
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at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask);
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st->last_value = 0;
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st->done = false;
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mutex_unlock(&st->lock);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = (st->vref_mv * 1000) >> chan->scan_type.realbits;
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*val2 = 0;
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return IIO_VAL_INT_PLUS_MICRO;
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default:
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break;
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}
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return -EINVAL;
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}
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static int at91_adc_probe_pdata(struct at91_adc_state *st,
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struct platform_device *pdev)
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{
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struct at91_adc_data *pdata = pdev->dev.platform_data;
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if (!pdata)
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return -EINVAL;
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st->use_external = pdata->use_external_triggers;
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st->vref_mv = pdata->vref;
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st->channels_mask = pdata->channels_used;
|
||||
st->num_channels = pdata->num_channels;
|
||||
st->startup_time = pdata->startup_time;
|
||||
st->trigger_number = pdata->trigger_number;
|
||||
st->trigger_list = pdata->trigger_list;
|
||||
st->registers = pdata->registers;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct iio_info at91_adc_info = {
|
||||
.driver_module = THIS_MODULE,
|
||||
.read_raw = &at91_adc_read_raw,
|
||||
};
|
||||
|
||||
static int __devinit at91_adc_probe(struct platform_device *pdev)
|
||||
{
|
||||
unsigned int prsc, mstrclk, ticks, adc_clk;
|
||||
int ret;
|
||||
struct iio_dev *idev;
|
||||
struct at91_adc_state *st;
|
||||
struct resource *res;
|
||||
|
||||
idev = iio_device_alloc(sizeof(struct at91_adc_state));
|
||||
if (idev == NULL) {
|
||||
ret = -ENOMEM;
|
||||
goto error_ret;
|
||||
}
|
||||
|
||||
st = iio_priv(idev);
|
||||
|
||||
ret = at91_adc_probe_pdata(st, pdev);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "No platform data available.\n");
|
||||
ret = -EINVAL;
|
||||
goto error_free_device;
|
||||
}
|
||||
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
if (!res) {
|
||||
dev_err(&pdev->dev, "No resource defined\n");
|
||||
ret = -ENXIO;
|
||||
goto error_ret;
|
||||
}
|
||||
|
||||
platform_set_drvdata(pdev, idev);
|
||||
|
||||
idev->dev.parent = &pdev->dev;
|
||||
idev->name = dev_name(&pdev->dev);
|
||||
idev->modes = INDIO_DIRECT_MODE;
|
||||
idev->info = &at91_adc_info;
|
||||
|
||||
st->irq = platform_get_irq(pdev, 0);
|
||||
if (st->irq < 0) {
|
||||
dev_err(&pdev->dev, "No IRQ ID is designated\n");
|
||||
ret = -ENODEV;
|
||||
goto error_free_device;
|
||||
}
|
||||
|
||||
if (!request_mem_region(res->start, resource_size(res),
|
||||
"AT91 adc registers")) {
|
||||
dev_err(&pdev->dev, "Resources are unavailable.\n");
|
||||
ret = -EBUSY;
|
||||
goto error_free_device;
|
||||
}
|
||||
|
||||
st->reg_base = ioremap(res->start, resource_size(res));
|
||||
if (!st->reg_base) {
|
||||
dev_err(&pdev->dev, "Failed to map registers.\n");
|
||||
ret = -ENOMEM;
|
||||
goto error_release_mem;
|
||||
}
|
||||
|
||||
/*
|
||||
* Disable all IRQs before setting up the handler
|
||||
*/
|
||||
at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
|
||||
at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
|
||||
ret = request_irq(st->irq,
|
||||
at91_adc_eoc_trigger,
|
||||
0,
|
||||
pdev->dev.driver->name,
|
||||
idev);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Failed to allocate IRQ.\n");
|
||||
goto error_unmap_reg;
|
||||
}
|
||||
|
||||
st->clk = clk_get(&pdev->dev, "adc_clk");
|
||||
if (IS_ERR(st->clk)) {
|
||||
dev_err(&pdev->dev, "Failed to get the clock.\n");
|
||||
ret = PTR_ERR(st->clk);
|
||||
goto error_free_irq;
|
||||
}
|
||||
|
||||
ret = clk_prepare(st->clk);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Could not prepare the clock.\n");
|
||||
goto error_free_clk;
|
||||
}
|
||||
|
||||
ret = clk_enable(st->clk);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Could not enable the clock.\n");
|
||||
goto error_unprepare_clk;
|
||||
}
|
||||
|
||||
st->adc_clk = clk_get(&pdev->dev, "adc_op_clk");
|
||||
if (IS_ERR(st->adc_clk)) {
|
||||
dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
|
||||
ret = PTR_ERR(st->clk);
|
||||
goto error_disable_clk;
|
||||
}
|
||||
|
||||
ret = clk_prepare(st->adc_clk);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Could not prepare the ADC clock.\n");
|
||||
goto error_free_adc_clk;
|
||||
}
|
||||
|
||||
ret = clk_enable(st->adc_clk);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Could not enable the ADC clock.\n");
|
||||
goto error_unprepare_adc_clk;
|
||||
}
|
||||
|
||||
/*
|
||||
* Prescaler rate computation using the formula from the Atmel's
|
||||
* datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
|
||||
* specified by the electrical characteristics of the board.
|
||||
*/
|
||||
mstrclk = clk_get_rate(st->clk);
|
||||
adc_clk = clk_get_rate(st->adc_clk);
|
||||
prsc = (mstrclk / (2 * adc_clk)) - 1;
|
||||
|
||||
if (!st->startup_time) {
|
||||
dev_err(&pdev->dev, "No startup time available.\n");
|
||||
ret = -EINVAL;
|
||||
goto error_disable_adc_clk;
|
||||
}
|
||||
|
||||
/*
|
||||
* Number of ticks needed to cover the startup time of the ADC as
|
||||
* defined in the electrical characteristics of the board, divided by 8.
|
||||
* The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
|
||||
*/
|
||||
ticks = round_up((st->startup_time * adc_clk /
|
||||
1000000) - 1, 8) / 8;
|
||||
at91_adc_writel(st, AT91_ADC_MR,
|
||||
(AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) |
|
||||
(AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP));
|
||||
|
||||
/* Setup the ADC channels available on the board */
|
||||
ret = at91_adc_channel_init(idev);
|
||||
if (ret < 0) {
|
||||
dev_err(&pdev->dev, "Couldn't initialize the channels.\n");
|
||||
goto error_disable_adc_clk;
|
||||
}
|
||||
|
||||
init_waitqueue_head(&st->wq_data_avail);
|
||||
mutex_init(&st->lock);
|
||||
|
||||
ret = at91_adc_buffer_init(idev);
|
||||
if (ret < 0) {
|
||||
dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
|
||||
goto error_disable_adc_clk;
|
||||
}
|
||||
|
||||
ret = at91_adc_trigger_init(idev);
|
||||
if (ret < 0) {
|
||||
dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
|
||||
goto error_unregister_buffer;
|
||||
}
|
||||
|
||||
ret = iio_device_register(idev);
|
||||
if (ret < 0) {
|
||||
dev_err(&pdev->dev, "Couldn't register the device.\n");
|
||||
goto error_remove_triggers;
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
||||
error_remove_triggers:
|
||||
at91_adc_trigger_remove(idev);
|
||||
error_unregister_buffer:
|
||||
at91_adc_buffer_remove(idev);
|
||||
error_disable_adc_clk:
|
||||
clk_disable(st->adc_clk);
|
||||
error_unprepare_adc_clk:
|
||||
clk_unprepare(st->adc_clk);
|
||||
error_free_adc_clk:
|
||||
clk_put(st->adc_clk);
|
||||
error_disable_clk:
|
||||
clk_disable(st->clk);
|
||||
error_unprepare_clk:
|
||||
clk_unprepare(st->clk);
|
||||
error_free_clk:
|
||||
clk_put(st->clk);
|
||||
error_free_irq:
|
||||
free_irq(st->irq, idev);
|
||||
error_unmap_reg:
|
||||
iounmap(st->reg_base);
|
||||
error_release_mem:
|
||||
release_mem_region(res->start, resource_size(res));
|
||||
error_free_device:
|
||||
iio_device_free(idev);
|
||||
error_ret:
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int __devexit at91_adc_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct iio_dev *idev = platform_get_drvdata(pdev);
|
||||
struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
struct at91_adc_state *st = iio_priv(idev);
|
||||
|
||||
iio_device_unregister(idev);
|
||||
at91_adc_trigger_remove(idev);
|
||||
at91_adc_buffer_remove(idev);
|
||||
clk_disable_unprepare(st->adc_clk);
|
||||
clk_put(st->adc_clk);
|
||||
clk_disable(st->clk);
|
||||
clk_unprepare(st->clk);
|
||||
clk_put(st->clk);
|
||||
free_irq(st->irq, idev);
|
||||
iounmap(st->reg_base);
|
||||
release_mem_region(res->start, resource_size(res));
|
||||
iio_device_free(idev);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct platform_driver at91_adc_driver = {
|
||||
.probe = at91_adc_probe,
|
||||
.remove = __devexit_p(at91_adc_remove),
|
||||
.driver = {
|
||||
.name = "at91_adc",
|
||||
},
|
||||
};
|
||||
|
||||
module_platform_driver(at91_adc_driver);
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
|
||||
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
|
||||
Loading…
Reference in a new issue