* [PATCH 2/3] ARM: AT91: IIO: Add AT91 ADC driver.
2011-11-30 9:14 [PATCH v11] AT91: Add a driver for the ADC Maxime Ripard
2011-11-30 9:15 ` [PATCH 1/3] ARM: AT91: Add platform data for the ADCs Maxime Ripard
@ 2011-11-30 9:15 ` Maxime Ripard
2011-11-30 17:40 ` Arnd Bergmann
2011-11-30 9:15 ` [PATCH 3/3] ARM: AT91: Add the ADC to the sam9g20ek board Maxime Ripard
2 siblings, 1 reply; 6+ messages in thread
From: Maxime Ripard @ 2011-11-30 9:15 UTC (permalink / raw)
To: linux-arm-kernel, linux-iio; +Cc: Patrice Vilchez, Thomas Petazzoni
Cc: Patrice Vilchez <patrice.vilchez@atmel.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
---
drivers/iio/adc/Kconfig | 6 +
drivers/iio/adc/Makefile | 4 +-
drivers/iio/adc/at91_adc.c | 333 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 342 insertions(+), 1 deletions(-)
create mode 100644 drivers/iio/adc/at91_adc.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 3d97b21..02ed274 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -14,6 +14,12 @@ config IIO_AD799X
i2c analog to digital convertors (ADC). Provides direct access
via sysfs.
+config IIO_AT91_ADC
+ tristate "Atmel AT91 ADC"
+ depends on SYSFS && ARCH_AT91
+ help
+ Say yes here to build support for Atmel AT91 ADC.
+
config IIO_MAX1363
tristate "Maxim max1363 ADC driver"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index c197334..50ceaab7 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -6,4 +6,6 @@ iio_ad799x-y := ad799x_core.o
obj-$(CONFIG_IIO_AD799X) += iio_ad799x.o
iio_max1363-y := max1363_core.o
-obj-$(CONFIG_IIO_MAX1363) += iio_max1363.o
\ No newline at end of file
+obj-$(CONFIG_IIO_MAX1363) += iio_max1363.o
+
+obj-$(CONFIG_IIO_AT91_ADC) += at91_adc.o
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
new file mode 100644
index 0000000..d4cbc06
--- /dev/null
+++ b/drivers/iio/adc/at91_adc.c
@@ -0,0 +1,333 @@
+/*
+ * Driver for the ADC present in the Atmel AT91 evaluation boards.
+ *
+ * Copyright 2011 Free Electrons
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#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 <linux/iio/iio.h>
+#include <linux/platform_data/at91_adc.h>
+
+#include <mach/board.h>
+#include <mach/at91_adc.h>
+
+struct at91_adc_state {
+ struct clk *clk;
+ bool done;
+ struct mutex lock;
+ int irq;
+ wait_queue_head_t wq_data_avail;
+ u16 last_value;
+ void __iomem *reg_base;
+ unsigned int vref_mv;
+ unsigned long channels_mask;
+};
+
+static inline u32 at91_adc_reg_read(struct at91_adc_state *st,
+ u8 reg)
+{
+ return readl_relaxed(st->reg_base + reg);
+}
+
+static inline void at91_adc_reg_write(struct at91_adc_state *st,
+ u8 reg,
+ u32 val)
+{
+ writel_relaxed(val, st->reg_base + reg);
+}
+
+static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
+{
+ struct iio_dev *idev = private;
+ struct at91_adc_state *st = iio_priv(idev);
+ unsigned int status = at91_adc_reg_read(st, AT91_ADC_SR);
+
+ if (!(status & AT91_ADC_DRDY))
+ return IRQ_HANDLED;
+
+ if (status & st->channels_mask) {
+ st->done = true;
+ st->last_value = at91_adc_reg_read(st, AT91_ADC_LCDR);
+ }
+
+ wake_up_interruptible(&st->wq_data_avail);
+
+ return IRQ_HANDLED;
+}
+
+static int at91_adc_channel_init(struct iio_dev *idev,
+ struct at91_adc_data *pdata)
+{
+ struct iio_chan_spec *chan_array;
+ int bit, idx = 0;
+
+ idev->num_channels = bitmap_weight(&pdata->channels_used,
+ pdata->num_channels);
+ chan_array = kcalloc(idev->num_channels, sizeof(struct iio_chan_spec),
+ GFP_KERNEL);
+
+ if (chan_array == NULL)
+ return -ENOMEM;
+
+ for_each_set_bit(bit, &pdata->channels_used, pdata->num_channels) {
+ struct iio_chan_spec *chan = chan_array + idx;
+ chan->type = IIO_VOLTAGE;
+ chan->indexed = 1;
+ chan->channel = bit;
+ chan->scan_type.sign = 'u';
+ chan->scan_type.realbits = 10;
+ chan->info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT;
+ idx++;
+ }
+
+ idev->channels = chan_array;
+ return idev->num_channels;
+}
+
+static void at91_adc_channel_remove(struct iio_dev *idev)
+{
+ kfree(idev->channels);
+}
+
+static int at91_adc_read_raw(struct iio_dev *idev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct at91_adc_state *st = iio_priv(idev);
+ int ret;
+
+ switch (mask) {
+ case 0:
+ mutex_lock(&st->lock);
+
+ at91_adc_reg_write(st, AT91_ADC_CHER,
+ AT91_ADC_CH(chan->channel));
+ at91_adc_reg_write(st, AT91_ADC_IER,
+ AT91_ADC_EOC(chan->channel));
+ at91_adc_reg_write(st, AT91_ADC_CR, AT91_ADC_START);
+
+ ret = wait_event_interruptible_timeout(st->wq_data_avail,
+ st->done,
+ msecs_to_jiffies(1000));
+ if (ret == 0)
+ return -ETIMEDOUT;
+ else if (ret < 0)
+ return ret;
+
+ *val = st->last_value;
+
+ at91_adc_reg_write(st, AT91_ADC_CHDR,
+ AT91_ADC_CH(chan->channel));
+ at91_adc_reg_write(st, AT91_ADC_IDR,
+ AT91_ADC_EOC(chan->channel));
+
+ st->last_value = 0;
+ st->done = false;
+ mutex_unlock(&st->lock);
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = (st->vref_mv * 1000) >> chan->scan_type.realbits;
+ *val2 = 0;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ break;
+ }
+ return -EINVAL;
+}
+
+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;
+ int ret;
+ struct iio_dev *idev;
+ struct at91_adc_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_device_allocate(sizeof(struct at91_adc_state));
+ if (idev == NULL) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+
+ platform_set_drvdata(pdev, idev);
+
+ idev->dev.parent = &pdev->dev;
+ idev->name = dev_name(&pdev->dev);
+ idev->info = &at91_adc_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
+ */
+ at91_adc_reg_write(st, AT91_ADC_CR, AT91_ADC_SWRST);
+ at91_adc_reg_write(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;
+ }
+
+ 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;
+ }
+
+ /*
+ * 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.
+ */
+ 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;
+ }
+
+ /*
+ * 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((pdata->startup_time * pdata->adc_clock /
+ 1000000) - 1, 8) / 8;
+ at91_adc_reg_write(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, pdata);
+ if (ret < 0)
+ goto error_free_clk;
+
+ init_waitqueue_head(&st->wq_data_avail);
+ mutex_init(&st->lock);
+
+ st->vref_mv = pdata->vref;
+ st->channels_mask = pdata->channels_used;
+
+ ret = iio_device_register(idev);
+ if (ret < 0)
+ goto error_free_channels;
+
+ return 0;
+
+error_free_channels:
+ at91_adc_channel_remove(idev);
+error_free_clk:
+ clk_disable(st->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_channel_remove(idev);
+ clk_disable(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>");
--
1.7.4.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/3] ARM: AT91: Add the ADC to the sam9g20ek board
2011-11-30 9:14 [PATCH v11] AT91: Add a driver for the ADC Maxime Ripard
2011-11-30 9:15 ` [PATCH 1/3] ARM: AT91: Add platform data for the ADCs Maxime Ripard
2011-11-30 9:15 ` [PATCH 2/3] ARM: AT91: IIO: Add AT91 ADC driver Maxime Ripard
@ 2011-11-30 9:15 ` Maxime Ripard
2 siblings, 0 replies; 6+ messages in thread
From: Maxime Ripard @ 2011-11-30 9:15 UTC (permalink / raw)
To: linux-arm-kernel, linux-iio
Cc: Patrice Vilchez, Thomas Petazzoni, Nicolas Ferre,
Jean-Christophe PLAGNIOL-VILLARD
Cc: Patrice Vilchez <patrice.vilchez@atmel.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
---
arch/arm/mach-at91/at91sam9260_devices.c | 62 ++++++++++++++++++++++++++++++
arch/arm/mach-at91/board-sam9g20ek.c | 13 ++++++
2 files changed, 75 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-at91/at91sam9260_devices.c b/arch/arm/mach-at91/at91sam9260_devices.c
index 39f81f4..012992b 100644
--- a/arch/arm/mach-at91/at91sam9260_devices.c
+++ b/arch/arm/mach-at91/at91sam9260_devices.c
@@ -16,6 +16,8 @@
#include <linux/platform_device.h>
#include <linux/i2c-gpio.h>
+#include <linux/platform_data/at91_adc.h>
+
#include <mach/board.h>
#include <mach/gpio.h>
#include <mach/cpu.h>
@@ -1312,6 +1314,66 @@ void __init at91_add_device_cf(struct at91_cf_data *data)
void __init at91_add_device_cf(struct at91_cf_data * data) {}
#endif
+/* --------------------------------------------------------------------
+ * ADCs
+ * -------------------------------------------------------------------- */
+
+#if defined(CONFIG_IIO_AT91_ADC) || defined(CONFIG_IIO_AT91_ADC_MODULE)
+static struct at91_adc_data adc_data;
+
+static struct resource adc_resources[] = {
+ [0] = {
+ .start = AT91SAM9260_BASE_ADC,
+ .end = AT91SAM9260_BASE_ADC + SZ_16K - 1,
+ .flags = IORESOURCE_MEM,
+ },
+ [1] = {
+ .start = AT91SAM9260_ID_ADC,
+ .end = AT91SAM9260_ID_ADC,
+ .flags = IORESOURCE_IRQ,
+ },
+};
+
+static struct platform_device at91_adc_device = {
+ .name = "at91_adc",
+ .id = -1,
+ .dev = {
+ .platform_data = &adc_data,
+ },
+ .resource = adc_resources,
+ .num_resources = ARRAY_SIZE(adc_resources),
+};
+
+void __init at91_add_device_adc(struct at91_adc_data *data)
+{
+ if (!data)
+ return;
+
+ if (test_bit(0, &data->channels_used))
+ at91_set_A_periph(AT91_PIN_PC0, 0);
+ if (test_bit(1, &data->channels_used))
+ at91_set_A_periph(AT91_PIN_PC1, 0);
+ if (test_bit(2, &data->channels_used))
+ at91_set_A_periph(AT91_PIN_PC2, 0);
+ if (test_bit(3, &data->channels_used))
+ at91_set_A_periph(AT91_PIN_PC3, 0);
+
+ /*
+ * The electrical characteristics part of the AT91SAM9G20 datasheet
+ * sets the ADC clock to 5MHz.
+ */
+ data->adc_clock = 5000000;
+
+ data->num_channels = 4;
+ data->startup_time = 10;
+
+ adc_data = *data;
+ platform_device_register(&at91_adc_device);
+}
+#else
+void __init at91_add_device_adc(struct at91_adc_data *data) {}
+#endif
+
/* -------------------------------------------------------------------- */
/*
* These devices are always present and don't need any board-specific
diff --git a/arch/arm/mach-at91/board-sam9g20ek.c b/arch/arm/mach-at91/board-sam9g20ek.c
index 817f59d..29dae9f 100644
--- a/arch/arm/mach-at91/board-sam9g20ek.c
+++ b/arch/arm/mach-at91/board-sam9g20ek.c
@@ -31,6 +31,8 @@
#include <linux/regulator/fixed.h>
#include <linux/regulator/consumer.h>
+#include <linux/platform_data/at91_adc.h>
+
#include <mach/hardware.h>
#include <asm/setup.h>
#include <asm/mach-types.h>
@@ -314,6 +316,15 @@ static void __init ek_add_device_buttons(void)
static void __init ek_add_device_buttons(void) {}
#endif
+/*
+ * ADCs
+ */
+
+static struct at91_adc_data ek_adc_data = {
+ .channels_used = BIT(0) | BIT(1) | BIT(2) | BIT(3),
+ .vref = 3300,
+};
+
#if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE)
static struct regulator_consumer_supply ek_audio_consumer_supplies[] = {
REGULATOR_SUPPLY("AVDD", "0-001b"),
@@ -389,6 +400,8 @@ static void __init ek_board_init(void)
ek_add_device_gpio_leds();
/* Push Buttons */
ek_add_device_buttons();
+ /* ADCs */
+ at91_add_device_adc(&ek_adc_data);
/* PCK0 provides MCLK to the WM8731 */
at91_set_B_periph(AT91_PIN_PC1, 0);
/* SSC (for WM8731) */
--
1.7.4.1
^ permalink raw reply related [flat|nested] 6+ messages in thread