From: Ismo Puustinen <ismo.puusti...@intel.com>
Galileo gen 2 has support for setting GPIO modes. Expose these
properties through the GPIO sysfs interface. This approach is bit hacky,
since it changes the interface semantics.
Original patch by Josef Ahmad <josef.ah...@linux.intel.com>.
Upstream-status: Forward-ported from Intel IOT Develper Kit Quark BSP.
Inappropriate for Linux upstream, since it changes the
sysfs GPIO userspace API. We need to keep this for
backwards compatibility. A better solution would be to
implement a pin control driver to handle the drive
states of the GPIO pins, but there isn't a userspace
interface yet for that.
Signed-off-by: Ismo Puustinen <ismo.puusti...@intel.com>
Signed-off-by: Saul Wold <s...@linux.intel.com>
---
drivers/gpio/gpio-pca953x.c | 57 +++++++++++++++++++++++++++----
drivers/gpio/gpiolib-sysfs.c | 78 +++++++++++++++++++++++++++++++++++++++++++
drivers/gpio/gpiolib.c | 18 ++++++++++
drivers/gpio/gpiolib.h | 7 +++-
include/asm-generic/gpio.h | 5 +++
include/linux/gpio.h | 10 ++++++
include/linux/gpio/consumer.h | 11 ++++++
include/linux/gpio/driver.h | 2 ++
8 files changed, 180 insertions(+), 8 deletions(-)
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 0227cde..8f49bd6 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -39,6 +39,9 @@
#define PCA957X_MSK 6
#define PCA957X_INTS 7
+#define PCA953X_PUPD_EN 35
+#define PCA953X_PUPD_SEL 36
+
#define PCA_GPIO_MASK 0x00FF
#define PCA_INT 0x0100
#define PCA953X_TYPE 0x1000
@@ -374,6 +377,43 @@ exit:
mutex_unlock(&chip->i2c_lock);
}
+static int pca953x_gpio_set_drive(struct gpio_chip *gc,
+ unsigned off, unsigned mode)
+{
+ struct pca953x_chip *chip;
+ int ret = 0;
+ int val;
+
+ chip = container_of(gc, struct pca953x_chip, gpio_chip);
+
+ if (chip->chip_type != PCA953X_TYPE)
+ return -EINVAL;
+
+ mutex_lock(&chip->i2c_lock);
+
+ switch (mode) {
+ case GPIOF_DRIVE_PULLUP:
+ ret = pca953x_write_single(chip, PCA953X_PUPD_EN, 1, off) ||
+ pca953x_write_single(chip, PCA953X_PUPD_SEL, 1,
off);
+ break;
+ case GPIOF_DRIVE_PULLDOWN:
+ ret = pca953x_write_single(chip, PCA953X_PUPD_EN, 1, off) ||
+ pca953x_write_single(chip, PCA953X_PUPD_SEL, 0,
off);
+ break;
+ case GPIOF_DRIVE_STRONG:
+ case GPIOF_DRIVE_HIZ:
+ ret = pca953x_read_single(chip, PCA953X_PUPD_EN, &val, off) ||
+ pca953x_write_single(chip, PCA953X_PUPD_EN, 0,
off) ||
+ pca953x_write_single(chip, PCA953X_PUPD_SEL,
val, off);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ mutex_unlock(&chip->i2c_lock);
+ return ret;
+}
+
static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
{
struct gpio_chip *gc;
@@ -392,6 +432,9 @@ static void pca953x_setup_gpio(struct pca953x_chip *chip,
int gpios)
gc->dev = &chip->client->dev;
gc->owner = THIS_MODULE;
gc->names = chip->names;
+
+ if (chip->chip_type == PCA953X_TYPE)
+ gc->set_drive = pca953x_gpio_set_drive;
}
#ifdef CONFIG_GPIO_PCA953X_IRQ
@@ -548,7 +591,7 @@ static irqreturn_t pca953x_irq_handler(int irq, void *devid)
}
static int pca953x_irq_setup(struct pca953x_chip *chip,
- int irq_base)
+ int irq_base)
{
struct i2c_client *client = chip->client;
int ret, i, offset = 0;
@@ -591,10 +634,10 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
}
ret = gpiochip_irqchip_add(&chip->gpio_chip,
- &pca953x_irq_chip,
- irq_base,
- handle_simple_irq,
- IRQ_TYPE_NONE);
+ &pca953x_irq_chip,
+ irq_base,
+ handle_simple_irq,
+ IRQ_TYPE_NONE);
if (ret) {
dev_err(&client->dev,
"could not connect irqchip to gpiochip\n");
@@ -607,7 +650,7 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
#else /* CONFIG_GPIO_PCA953X_IRQ */
static int pca953x_irq_setup(struct pca953x_chip *chip,
- int irq_base)
+ int irq_base)
{
struct i2c_client *client = chip->client;
@@ -628,7 +671,7 @@ static int device_pca953x_init(struct pca953x_chip *chip,
u32 invert)
goto out;
ret = pca953x_read_regs(chip, PCA953X_DIRECTION,
- chip->reg_direction);
+ chip->reg_direction);
if (ret)
goto out;
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index af3bc7a..4f90f69 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -6,6 +6,7 @@
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/kdev_t.h>
+#include <linux/gpio.h>
#include "gpiolib.h"
@@ -356,6 +357,82 @@ static ssize_t gpio_active_low_store(struct device *dev,
static DEVICE_ATTR(active_low, 0644,
gpio_active_low_show, gpio_active_low_store);
+
+static ssize_t gpio_drive_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags)) {
+ status = -EIO;
+ } else {
+ if (test_bit(FLAG_PULLUP, &desc->flags))
+ status = sprintf(buf, "pullup\n");
+ else if (test_bit(FLAG_PULLDOWN, &desc->flags))
+ status = sprintf(buf, "pulldown\n");
+ else if (test_bit(FLAG_STRONG, &desc->flags))
+ status = sprintf(buf, "strong\n");
+ else if (test_bit(FLAG_HIZ, &desc->flags))
+ status = sprintf(buf, "hiz\n");
+ else
+ status = -EINVAL;
+ }
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static ssize_t gpio_drive_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else {
+ if (sysfs_streq(buf, "pullup")) {
+ status = gpiod_set_drive(desc, GPIOF_DRIVE_PULLUP);
+ if (!status) {
+ desc->flags &= ~GPIO_DRIVE_MASK;
+ set_bit(FLAG_PULLUP, &desc->flags);
+ }
+ } else if (sysfs_streq(buf, "pulldown")) {
+ status = gpiod_set_drive(desc, GPIOF_DRIVE_PULLDOWN);
+ if (!status) {
+ desc->flags &= ~GPIO_DRIVE_MASK;
+ set_bit(FLAG_PULLDOWN, &desc->flags);
+ }
+ } else if (sysfs_streq(buf, "strong")) {
+ status = gpiod_set_drive(desc, GPIOF_DRIVE_STRONG);
+ if (!status) {
+ desc->flags &= ~GPIO_DRIVE_MASK;
+ set_bit(FLAG_STRONG, &desc->flags);
+ }
+ } else if (sysfs_streq(buf, "hiz")) {
+ status = gpiod_set_drive(desc, GPIOF_DRIVE_HIZ);
+ if (!status) {
+ desc->flags &= ~GPIO_DRIVE_MASK;
+ set_bit(FLAG_HIZ, &desc->flags);
+ }
+ } else {
+ status = -EINVAL;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+ return status ? : size;
+}
+
+static const DEVICE_ATTR(drive, 0644,
+ gpio_drive_show, gpio_drive_store);
+
+
static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
int n)
{
@@ -382,6 +459,7 @@ static struct attribute *gpio_attrs[] = {
&dev_attr_edge.attr,
&dev_attr_value.attr,
&dev_attr_active_low.attr,
+ &dev_attr_drive.attr,
NULL,
};
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 6bc612b..038159b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1127,6 +1127,24 @@ int gpiod_is_active_low(const struct gpio_desc *desc)
}
EXPORT_SYMBOL_GPL(gpiod_is_active_low);
+int gpiod_set_drive(struct gpio_desc *desc, unsigned mode)
+{
+ unsigned long flags;
+ struct gpio_chip *chip;
+
+ chip = desc->chip;
+ if (!chip || !chip->set || !chip->set_drive)
+ goto fail;
+
+ might_sleep_if(chip->can_sleep);
+
+ return chip->set_drive(chip, gpio_chip_hwgpio(desc), mode);
+
+fail:
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(gpiod_set_drive);
+
/* I/O calls are only valid after configuration completed; the relevant
* "is this a valid GPIO" error checks should already have been done.
*
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 594b179..2ffc2e6 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -91,12 +91,17 @@ struct gpio_desc {
#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
#define FLAG_SYSFS_DIR 10 /* show sysfs direction attribute */
#define FLAG_IS_HOGGED 11 /* GPIO is hogged */
+#define FLAG_PULLUP 12 /* Gpio drive is resistive pullup */
+#define FLAG_PULLDOWN 13 /* Gpio drive is resistive pulldown */
+#define FLAG_STRONG 14 /* Gpio drive is strong (fast output) */
+#define FLAG_HIZ 15 /* Gpio drive is Hi-Z (input) */
#define ID_SHIFT 16 /* add new flags before this one */
#define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1)
#define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
-
+#define GPIO_DRIVE_MASK (BIT(FLAG_PULLUP) | BIT(FLAG_PULLDOWN)
\
+ | BIT(FLAG_STRONG) | BIT(FLAG_HIZ))
const char *label;
};
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 9bb0d11..21c9497 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -76,6 +76,11 @@ static inline int gpio_set_debounce(unsigned gpio, unsigned
debounce)
return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
}
+static inline int gpio_set_drive(unsigned gpio, unsigned mode)
+{
+ return gpiod_set_drive(gpio_to_desc(gpio), mode);
+}
+
static inline int gpio_get_value_cansleep(unsigned gpio)
{
return gpiod_get_raw_value_cansleep(gpio_to_desc(gpio));
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index ab81339..c22f1f6 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -30,6 +30,11 @@
#define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
+#define GPIOF_DRIVE_PULLUP (1 << 7)
+#define GPIOF_DRIVE_PULLDOWN (1 << 8)
+#define GPIOF_DRIVE_STRONG (1 << 9)
+#define GPIOF_DRIVE_HIZ (1 << 10)
+
/**
* struct gpio - a structure describing a GPIO with configuration
* @gpio: the GPIO number
@@ -148,6 +153,11 @@ static inline int gpio_set_debounce(unsigned gpio,
unsigned debounce)
return -ENOSYS;
}
+static inline int gpio_set_drive(unsigned gpio, unsigned mode)
+{
+ return -ENOSYS;
+}
+
static inline int gpio_get_value(unsigned gpio)
{
/* GPIO can never have been requested or set as {in,out}put */
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index da04265..ecdbc74 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -121,6 +121,8 @@ void gpiod_set_raw_array_cansleep(unsigned int array_size,
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
+int gpiod_set_drive(struct gpio_desc *desc, unsigned mode);
+
int gpiod_is_active_low(const struct gpio_desc *desc);
int gpiod_cansleep(const struct gpio_desc *desc);
@@ -375,6 +377,15 @@ static inline int gpiod_set_debounce(struct gpio_desc
*desc, unsigned debounce)
return -ENOSYS;
}
+
+static inline int gpiod_set_drive(unsigned gpio, unsigned mode)
+{
+ /* GPIO can never have been requested */
+ WARN_ON(1);
+ return -ENOSYS;
+}
+
+
static inline int gpiod_is_active_low(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index f1b3659..2f19b34 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -97,6 +97,8 @@ struct gpio_chip {
int (*set_debounce)(struct gpio_chip *chip,
unsigned offset,
unsigned debounce);
+ int (*set_drive)(struct gpio_chip *chip,
+ unsigned offset, unsigned mode);
int (*to_irq)(struct gpio_chip *chip,
unsigned offset);
--
2.5.0
--
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