[linux-yocto] [PATCH 27/29] gpio-pca953x: add "drive" property.
Saul Wold
sgw at linux.intel.com
Fri Feb 5 06:53:44 PST 2016
From: Ismo Puustinen <ismo.puustinen at 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.
The original patch was by Josef Ahmad <josef.ahmad at linux.intel.com> and
made on top of kernel 3.8.
Signed-off-by: Ismo Puustinen <ismo.puustinen at intel.com>
Signed-off-by: Saul Wold <sgw at 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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