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Message-ID: <20160613130628.GA28944@sophia>
Date: Mon, 13 Jun 2016 09:06:48 -0400
From: William Breathitt Gray <vilhelm.gray@...il.com>
To: jic23@...nel.org, knaack.h@....de, lars@...afoo.de,
pmeerw@...erw.net, linus.walleij@...aro.org
Cc: gnurou@...il.com, linux-gpio@...r.kernel.org,
linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3] iio: stx104: Add GPIO support for the Apex Embedded
Systems STX104
The Apex Embedded Systems STX104 device features eight lines of digital
I/O (four digital inputs and four digital outputs). This patch adds GPIO
support for these eight lines of digital I/O via GPIOLIB.
Cc: Linus Walleij <linus.walleij@...aro.org>
Cc: Alexandre Courbot <gnurou@...il.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@...il.com>
---
Changes in v3:
- Revert v2 change; any arch should be able to select GPIOLIB
- Return -EINVAL when attempting to set a GPIO to a direction it
cannot be
- Call stx104_gpio_set to have an initial value when setting a GPIO to
output direction
Changes in v2:
- Change GPIOLIB Kconfig selection to a dependency for the STX104
Kconfig option; STX104 should only be available to systems
configured for GPIOLIB
drivers/iio/dac/Kconfig | 11 +++--
drivers/iio/dac/stx104.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 129 insertions(+), 7 deletions(-)
diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index 61d5008..b3feb0bf 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -246,13 +246,14 @@ config MCP4922
will be called mcp4922.
config STX104
- tristate "Apex Embedded Systems STX104 DAC driver"
+ tristate "Apex Embedded Systems STX104 driver"
depends on ISA
+ select GPIOLIB
help
- Say yes here to build support for the 2-channel DAC on the Apex
- Embedded Systems STX104 integrated analog PC/104 card. The base port
- addresses for the devices may be configured via the "base" module
- parameter array.
+ Say yes here to build support for the 2-channel DAC and GPIO on the
+ Apex Embedded Systems STX104 integrated analog PC/104 card. The base
+ port addresses for the devices may be configured via the base array
+ module parameter.
config VF610_DAC
tristate "Vybrid vf610 DAC driver"
diff --git a/drivers/iio/dac/stx104.c b/drivers/iio/dac/stx104.c
index 174f4b7..e0f31a1 100644
--- a/drivers/iio/dac/stx104.c
+++ b/drivers/iio/dac/stx104.c
@@ -14,6 +14,7 @@
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
+#include <linux/gpio/driver.h>
#include <linux/iio/iio.h>
#include <linux/iio/types.h>
#include <linux/io.h>
@@ -21,6 +22,7 @@
#include <linux/isa.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
+#include <linux/spinlock.h>
#define STX104_NUM_CHAN 2
@@ -56,6 +58,20 @@ struct stx104_iio {
unsigned base;
};
+/**
+ * struct stx104_gpio - GPIO device private data structure
+ * @chip: instance of the gpio_chip
+ * @lock: synchronization lock to prevent I/O race conditions
+ * @base: base port address of the GPIO device
+ * @out_state: output bits state
+ */
+struct stx104_gpio {
+ struct gpio_chip chip;
+ spinlock_t lock;
+ unsigned int base;
+ unsigned int out_state;
+};
+
static int stx104_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val, int *val2, long mask)
{
@@ -95,15 +111,81 @@ static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = {
STX104_CHAN(1)
};
+static int stx104_gpio_get_direction(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ if (offset < 4)
+ return 1;
+
+ return 0;
+}
+
+static int stx104_gpio_direction_input(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ if (offset >= 4)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int stx104_gpio_direction_output(struct gpio_chip *chip,
+ unsigned int offset, int value)
+{
+ if (offset < 4)
+ return -EINVAL;
+
+ chip->set(chip, offset, value);
+ return 0;
+}
+
+static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
+
+ if (offset >= 4)
+ return -EINVAL;
+
+ return !!(inb(stx104gpio->base) & BIT(offset));
+}
+
+static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
+{
+ struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
+ const unsigned int mask = BIT(offset) >> 4;
+ unsigned long flags;
+
+ if (offset < 4)
+ return;
+
+ spin_lock_irqsave(&stx104gpio->lock, flags);
+
+ if (value)
+ stx104gpio->out_state |= mask;
+ else
+ stx104gpio->out_state &= ~mask;
+
+ outb(stx104gpio->out_state, stx104gpio->base);
+
+ spin_unlock_irqrestore(&stx104gpio->lock, flags);
+}
+
static int stx104_probe(struct device *dev, unsigned int id)
{
struct iio_dev *indio_dev;
struct stx104_iio *priv;
+ struct stx104_gpio *stx104gpio;
+ int err;
indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
if (!indio_dev)
return -ENOMEM;
+ stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
+ if (!stx104gpio)
+ return -ENOMEM;
+
if (!devm_request_region(dev, base[id], STX104_EXTENT,
dev_name(dev))) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
@@ -124,14 +206,53 @@ static int stx104_probe(struct device *dev, unsigned int id)
outw(0, base[id] + 4);
outw(0, base[id] + 6);
- return devm_iio_device_register(dev, indio_dev);
+ err = devm_iio_device_register(dev, indio_dev);
+ if (err) {
+ dev_err(dev, "IIO device registering failed (%d)\n", err);
+ return err;
+ }
+
+ stx104gpio->chip.label = dev_name(dev);
+ stx104gpio->chip.parent = dev;
+ stx104gpio->chip.owner = THIS_MODULE;
+ stx104gpio->chip.base = -1;
+ stx104gpio->chip.ngpio = 8;
+ stx104gpio->chip.get_direction = stx104_gpio_get_direction;
+ stx104gpio->chip.direction_input = stx104_gpio_direction_input;
+ stx104gpio->chip.direction_output = stx104_gpio_direction_output;
+ stx104gpio->chip.get = stx104_gpio_get;
+ stx104gpio->chip.set = stx104_gpio_set;
+ stx104gpio->base = base[id] + 3;
+ stx104gpio->out_state = 0x0;
+
+ spin_lock_init(&stx104gpio->lock);
+
+ dev_set_drvdata(dev, stx104gpio);
+
+ err = gpiochip_add_data(&stx104gpio->chip, stx104gpio);
+ if (err) {
+ dev_err(dev, "GPIO registering failed (%d)\n", err);
+ return err;
+ }
+
+ return 0;
+}
+
+static int stx104_remove(struct device *dev, unsigned int id)
+{
+ struct stx104_gpio *const stx104gpio = dev_get_drvdata(dev);
+
+ gpiochip_remove(&stx104gpio->chip);
+
+ return 0;
}
static struct isa_driver stx104_driver = {
.probe = stx104_probe,
.driver = {
.name = "stx104"
- }
+ },
+ .remove = stx104_remove
};
static void __exit stx104_exit(void)
--
2.7.3
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