On 03/06/16 18:42, William Breathitt Gray wrote:
> 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.
>
> Signed-off-by: William Breathitt Gray <vilhelm.g...@gmail.com>
This is a gpio chip support patch. Even though the driver is in IIO we
need to get it reviewed by appropriate maintainer.
Cc'd Linus, Alexandre and the list.
> ---
> 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 | 118
> ++++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 122 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index 61d5008..35a3d49 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
> + depends on 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..dc445cf 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 +111,74 @@ 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)
> +{
> + return 0;
> +}
> +
> +static int stx104_gpio_direction_output(struct gpio_chip *chip,
> + unsigned int offset, int value)
> +{
> + return 0;
Not return an error if the relevant pin can't be an output?
> +}
> +
> +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 +199,53 @@ 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)
>
