[PATCH 2/3] ARM: AT91: IIO: Add AT91 ADC driver.

Maxime Ripard
2011-11-03T10:11:09Z

Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Patrice Vilchez <patrice.vilchez@atmel.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
drivers/staging/iio/adc/Kconfig | 6 +
drivers/staging/iio/adc/Makefile | 1 +
drivers/staging/iio/adc/at91adc.c | 310 +++++++++++++++++++++++++++++++++++++
3 files changed, 317 insertions(+), 0 deletions(-)
create mode 100644 drivers/staging/iio/adc/at91adc.c

diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
index d9decea..c384894 100644
--- a/drivers/staging/iio/adc/Kconfig
+++ b/drivers/staging/iio/adc/Kconfig
@@ -169,6 +169,12 @@ config AD7280
To compile this driver as a module, choose M here: the
module will be called ad7280a

+config AT91ADC
+ tristate "Atmel AT91 ADC"
+ depends on SYSFS && ARCH_AT91
+ help
+ Say yes here to build support for Atmel AT91 ADC.
+
config MAX1363
tristate "Maxim max1363 ADC driver"
depends on I2C
diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
index ceee7f3..d250d06 100644
--- a/drivers/staging/iio/adc/Makefile
+++ b/drivers/staging/iio/adc/Makefile
@@ -37,3 +37,4 @@ obj-$(CONFIG_AD7192) += ad7192.o
obj-$(CONFIG_ADT7310) += adt7310.o
obj-$(CONFIG_ADT7410) += adt7410.o
obj-$(CONFIG_AD7280) += ad7280a.o
+obj-$(CONFIG_AT91ADC) += at91adc.o
diff --git a/drivers/staging/iio/adc/at91adc.c b/drivers/staging/iio/adc/at91adc.c
new file mode 100644
index 0000000..acf656d
--- /dev/null
+++ b/drivers/staging/iio/adc/at91adc.c
@@ -0,0 +1,310 @@
+/*
+ * Driver for the TouchScreen ADC Controller present in the Atmel AT91
+ * evaluation boards.
+ *
+ * Copyright 2011 Free Electrons
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#include "../iio.h"
+
+#include <mach/at91_adc.h>
+#include <mach/board.h>
+
+#define at91adc_reg_read(base, reg) readl_relaxed((base) + (reg))
+#define at91adc_reg_write(base, reg, val) writel_relaxed((val), (base) + (reg))
+
+struct at91adc_state {
+ struct clk *clk;
+ bool done;
+ struct mutex lock;
+ struct iio_chan_spec *channels;
+ int nb_chan;
+ int irq;
+ wait_queue_head_t wq_data_avail;
+ u16 lcdr;
+ void __iomem *reg_base;
+ unsigned int vref_mv;
+};
+
+static irqreturn_t at91adc_eoc_trigger(int irq, void *private)
+{
+ int chan;
+ struct at91adc_state *st = private;
+ unsigned int status = at91adc_reg_read(st->reg_base, AT91_ADC_SR);
+
+ if (!(status & AT91_ADC_DRDY))
+ return IRQ_HANDLED;
+
+ for (chan = 0; chan < st->nb_chan; chan++) {
+ if (status & AT91_ADC_EOC(chan)) {
+ st->done = true;
+ st->lcdr = at91adc_reg_read(st->reg_base,
+ AT91_ADC_CHR(chan));
+ }
+ }
+ wake_up_interruptible(&st->wq_data_avail);
+
+ return IRQ_HANDLED;
+}
+
+static int at91adc_channel_init(struct at91adc_state *st,
+ struct at91_adc_data *pdata)
+{
+ int i, idx = 0;
+ st->channels = kcalloc(pdata->num_channels_used,
+ sizeof(struct iio_chan_spec), GFP_KERNEL);
+ if (st->channels == NULL)
+ return -ENOMEM;
+
+ for (i = 0; i < st->nb_chan; i++) {
+ if(pdata->channels_used[i]) {
+ struct iio_chan_spec *chan = st->channels + idx;
+ chan->type = IIO_VOLTAGE;
+ chan->indexed = 1;
+ chan->channel = i;
+ chan->scan_type.sign = 's';
+ chan->scan_type.realbits = 10;
+ chan->scan_type.storagebits = 32;
+ chan->scan_type.shift = 0;
+ chan->info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT;
+ ++idx;
+ }
+ }
+
+ return st->nb_chan;
+}
+
+static int at91adc_read_raw(struct iio_dev *idev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct at91adc_state *st = iio_priv(idev);
+ unsigned int scale_uv;
+
+ switch (mask) {
+ case 0:
+ mutex_lock(&st->lock);
+
+ at91adc_reg_write(st->reg_base, AT91_ADC_CHER,
+ AT91_ADC_CH(chan->channel));
+ at91adc_reg_write(st->reg_base, AT91_ADC_IER,
+ AT91_ADC_EOC(chan->channel));
+ at91adc_reg_write(st->reg_base, AT91_ADC_CR, AT91_ADC_START);
+
+ wait_event_interruptible_timeout(st->wq_data_avail, st->done,
+ msecs_to_jiffies(10 * 1000));
+ *val = st->lcdr;
+
+ at91adc_reg_write(st->reg_base, AT91_ADC_CHDR,
+ AT91_ADC_CH(chan->channel));
+ at91adc_reg_write(st->reg_base, AT91_ADC_IDR,
+ AT91_ADC_EOC(chan->channel));
+
+ st->lcdr = 0;
+ st->done = false;
+ mutex_unlock(&st->lock);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ scale_uv = (st->vref_mv * 1000) >> chan->scan_type.realbits;
+ *val = scale_uv / 1000;
+ *val2 = (scale_uv % 1000) * 1000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ break;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_info at91adc_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = &at91adc_read_raw,
+};
+
+static int __devinit at91adc_probe(struct platform_device *pdev)
+{
+ unsigned int prsc, mstrclk, ticks;
+ int ret;
+ struct iio_dev *idev;
+ struct at91adc_state *st;
+ struct resource *res;
+ struct at91_adc_data *pdata = pdev->dev.platform_data;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "No resource defined\n");
+ ret = -ENXIO;
+ goto error_ret;
+ }
+
+ idev = iio_allocate_device(sizeof(struct at91adc_state));
+ if (idev == NULL) {
+ dev_err(&pdev->dev, "Failed to allocate memory.\n");
+ ret = -ENOMEM;
+ 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 = &at91adc_info;
+
+ st = iio_priv(idev);
+ 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
+ */
+ at91adc_reg_write(st->reg_base, AT91_ADC_CR, AT91_ADC_SWRST);
+ at91adc_reg_write(st->reg_base, AT91_ADC_IDR, 0xFFFFFFFF);
+ ret = request_irq(st->irq,
+ at91adc_eoc_trigger, 0, pdev->dev.driver->name, st);
+ 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;
+ }
+
+ clk_enable(st->clk);
+ mstrclk = clk_get_rate(st->clk);
+
+ if (!pdata) {
+ dev_err(&pdev->dev, "No platform data available.\n");
+ ret = -EINVAL;
+ goto error_free_clk;
+ }
+
+ if (!pdata->adc_clock) {
+ dev_err(&pdev->dev, "No ADCClock available.\n");
+ ret = -EINVAL;
+ goto error_free_clk;
+ }
+
+ prsc = (mstrclk / (2 * pdata->adc_clock)) - 1;
+
+ if (!pdata->startup_time) {
+ dev_err(&pdev->dev, "No startup time available.\n");
+ ret = -EINVAL;
+ goto error_free_clk;
+ }
+
+ ticks = round_up((pdata->startup_time * pdata->adc_clock /
+ 1000000) - 1, 8) / 8;
+ at91adc_reg_write(st->reg_base, 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 */
+ st->nb_chan = pdata->num_channels;
+ ret = at91adc_channel_init(st, pdata);
+ if (ret < 0) {
+ goto error_free_clk;
+ }
+
+ idev->channels = st->channels;
+ idev->num_channels = pdata->num_channels_used;
+
+ init_waitqueue_head(&st->wq_data_avail);
+ mutex_init(&st->lock);
+
+ st->vref_mv = pdata->vref;
+
+ ret = iio_device_register(idev);
+ if (ret < 0) {
+ goto error_free_clk;
+ }
+
+ return 0;
+
+error_free_clk:
+ clk_disable(st->clk);
+ clk_put(st->clk);
+error_free_irq:
+ free_irq(st->irq, st);
+error_unmap_reg:
+ iounmap(st->reg_base);
+error_release_mem:
+ release_mem_region(res->start, resource_size(res));
+error_free_device:
+ iio_free_device(idev);
+error_ret:
+ return ret;
+}
+
+static int __devexit at91adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *idev = platform_get_drvdata(pdev);
+ struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ struct at91adc_state *st = iio_priv(idev);
+
+ iio_device_unregister(idev);
+ free_irq(st->irq, st);
+ iounmap(st->reg_base);
+ release_mem_region(res->start, resource_size(res));
+ iio_free_device(idev);
+
+ return 0;
+}
+
+static struct platform_driver at91adc_driver = {
+ .probe = at91adc_probe,
+ .remove = __devexit_p(at91adc_remove),
+ .driver = {
+ .name = "at91adc",
+ },
+};
+
+static int __init at91adc_init(void)
+{
+ return platform_driver_register(&at91adc_driver);
+}
+
+static void __exit at91adc_exit(void)
+{
+ platform_driver_unregister(&at91adc_driver);
+}
+
+module_init(at91adc_init);
+module_exit(at91adc_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
--
1.7.4.1