* [PATCH 1/6 v8] gpio: Add a block GPIO API to gpiolib
2012-11-30 18:03 [PATCH 0/6 v8] gpio: Add block GPIO Roland Stigge
@ 2012-11-30 18:03 ` Roland Stigge
2012-11-30 18:03 ` [PATCH 2/6 v8] gpio: Add sysfs support to block GPIO API Roland Stigge
` (5 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Roland Stigge @ 2012-11-30 18:03 UTC (permalink / raw)
To: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr, wg
Cc: Roland Stigge
The recurring task of providing simultaneous access to GPIO lines (especially
for bit banging protocols) needs an appropriate API.
This patch adds a kernel internal "Block GPIO" API that enables simultaneous
access to several GPIOs. This is done by abstracting GPIOs to an n-bit word:
Once requested, it provides access to a group of GPIOs which can range over
multiple GPIO chips.
Signed-off-by: Roland Stigge <stigge@antcom.de>
---
Documentation/gpio.txt | 58 +++++++++++
drivers/gpio/gpiolib.c | 227 +++++++++++++++++++++++++++++++++++++++++++++
include/asm-generic/gpio.h | 17 +++
include/linux/gpio.h | 97 +++++++++++++++++++
4 files changed, 399 insertions(+)
--- linux-2.6.orig/Documentation/gpio.txt
+++ linux-2.6/Documentation/gpio.txt
@@ -439,6 +439,64 @@ slower clock delays the rising edge of S
signaling rate accordingly.
+Block GPIO
+----------
+
+The above described interface concentrates on handling single GPIOs. However,
+in applications where it is critical to set several GPIOs at once, this
+interface doesn't work well, e.g. bit-banging protocols via grouped GPIO lines.
+Consider a GPIO controller that is connected via a slow I2C line. When
+switching two or more GPIOs one after another, there can be considerable time
+between those events. This is solved by an interface called Block GPIO:
+
+struct gpio_block *gpio_block_create(unsigned int *gpios, size_t size,
+ const char *name);
+
+This creates a new block of GPIOs as a list of GPIO numbers with the specified
+size which are accessible via the returned struct gpio_block and the accessor
+functions described below. Please note that you need to request the GPIOs
+separately via gpio_request(). Similarly, the direction of the used GPIOs need
+to be set by the user before using the block. An arbitrary list of globally
+valid GPIOs can be specified, even ranging over several gpio_chips. Actual
+handling of I/O operations will be done on a best effort base, i.e.
+simultaneous I/O only where possible by hardware and implemented in the
+respective GPIO driver. The number of GPIOs in one block is limited to the
+number of bits in an unsigned long, or BITS_PER_LONG, of the respective
+platform, i.e. typically at least 32 on a 32 bit system, and at least 64 on a
+64 bit system. However, several blocks can be defined at once.
+
+unsigned long gpio_block_get(struct gpio_block *block, unsigned long mask);
+void gpio_block_set(struct gpio_block *block, unsigned long mask,
+ unsigned long values);
+
+With those accessor functions, setting and getting the GPIO values is possible,
+analogous to gpio_get_value() and gpio_set_value(). Each bit in the return
+value of gpio_block_get() and in the value argument of gpio_block_set()
+corresponds to a bit specified on gpio_block_create(). The mask parameters
+specify which bits in the block are acted upon. This is useful to let some bits
+untouched when doing a set operation on the block.
+
+Block operations in hardware are only possible where the respective GPIO driver
+implements it, falling back to using single GPIO operations where the driver
+only implements single GPIO access.
+
+If a GPIO block includes GPIOs from several chips, the chips are handled one
+after another in the order of first specification in the list of GPIOs defined
+in the GPIO block, starting with bit 0. Note that in this case, you typically
+can't assume simultaneous access.
+
+void gpio_block_free(struct gpio_block *block);
+
+After the GPIO block isn't used anymore, it should be free'd via
+gpio_block_free().
+
+int gpio_block_register(struct gpio_block *block);
+void gpio_block_unregister(struct gpio_block *block);
+
+These functions can be used to register a GPIO block. Blocks registered this
+way will be available via userspace API.
+
+
What do these conventions omit?
===============================
One of the biggest things these conventions omit is pin multiplexing, since
--- linux-2.6.orig/drivers/gpio/gpiolib.c
+++ linux-2.6/drivers/gpio/gpiolib.c
@@ -83,6 +83,8 @@ static inline void desc_set_label(struct
#endif
}
+static LIST_HEAD(gpio_block_list);
+
/* Warn when drivers omit gpio_request() calls -- legal but ill-advised
* when setting direction, and otherwise illegal. Until board setup code
* and drivers use explicit requests everywhere (which won't happen when
@@ -191,6 +193,16 @@ err:
return ret;
}
+static bool gpio_block_is_output(struct gpio_block *block)
+{
+ int i;
+
+ for (i = 0; i < block->ngpio; i++)
+ if (!test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags))
+ return false;
+ return true;
+}
+
#ifdef CONFIG_GPIO_SYSFS
/* lock protects against unexport_gpio() being called while
@@ -1680,6 +1692,221 @@ void __gpio_set_value(unsigned gpio, int
}
EXPORT_SYMBOL_GPL(__gpio_set_value);
+static struct gpio_block_chip *gpio_block_chip_get(struct gpio_block *block,
+ struct gpio_chip *gc)
+{
+ struct gpio_block_chip *i;
+
+ list_for_each_entry(i, &block->gbc_list, list)
+ if (i->gc == gc)
+ return i;
+ return NULL;
+}
+
+struct gpio_block *gpio_block_create(unsigned *gpios, size_t size,
+ const char *name)
+{
+ struct gpio_block *block;
+ struct gpio_block_chip *gbc;
+ struct gpio_remap *remap;
+ int i;
+
+ if (size < 1 || size > BITS_PER_LONG)
+ return ERR_PTR(-EINVAL);
+
+ for (i = 0; i < size; i++)
+ if (!gpio_is_valid(gpios[i]))
+ return ERR_PTR(-EINVAL);
+
+ block = kzalloc(sizeof(struct gpio_block), GFP_KERNEL);
+ if (!block)
+ return ERR_PTR(-ENOMEM);
+
+ block->name = name;
+ block->ngpio = size;
+ INIT_LIST_HEAD(&block->gbc_list);
+ block->gpio = kzalloc(sizeof(*block->gpio) * size, GFP_KERNEL);
+ if (!block->gpio)
+ goto err;
+
+ memcpy(block->gpio, gpios, sizeof(*block->gpio) * size);
+
+ for (i = 0; i < size; i++) {
+ struct gpio_chip *gc = gpio_to_chip(gpios[i]);
+ int bit = gpios[i] - gc->base;
+ gbc = gpio_block_chip_get(block, gc);
+
+ if (!gbc) {
+ gbc = kzalloc(sizeof(struct gpio_block_chip),
+ GFP_KERNEL);
+ if (!gbc)
+ goto err;
+ list_add_tail(&gbc->list, &block->gbc_list);
+ gbc->gc = gc;
+ INIT_LIST_HEAD(&gbc->remap_list);
+ }
+
+ /*
+ * represents the mask necessary on calls to the driver's
+ * .get_block() and .set_block()
+ */
+ gbc->mask |= BIT(bit);
+
+ /*
+ * collect gpios that are specified together, represented by
+ * neighboring bits
+ *
+ * get last element and create new element if list empty or
+ * new element necessary
+ */
+ remap = list_entry(gbc->remap_list.prev, struct gpio_remap,
+ list);
+ if (list_empty(&gbc->remap_list) ||
+ (bit - i != remap->offset)) {
+ remap = kzalloc(sizeof(struct gpio_remap), GFP_KERNEL);
+ if (!remap)
+ goto err;
+ list_add_tail(&remap->list, &gbc->remap_list);
+ remap->offset = bit - i;
+ }
+
+ /*
+ * represents the mask necessary for bit reordering between
+ * gpio_block (i.e. as specified on gpio_block_get() and
+ * gpio_block_set()) and gpio_chip domain (i.e. as specified on
+ * the driver's .set_block() and .get_block())
+ */
+ remap->mask |= BIT(i);
+ }
+
+ return block;
+err:
+ gpio_block_free(block);
+ return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(gpio_block_create);
+
+void gpio_block_free(struct gpio_block *block)
+{
+ struct list_head *i, *itmp, *j, *jtmp;
+ struct gpio_block_chip *gbc;
+ struct gpio_remap *remap;
+
+ list_for_each_safe(i, itmp, &block->gbc_list) {
+ gbc = list_entry(i, struct gpio_block_chip, list);
+ list_del(i);
+ list_for_each_safe(j, jtmp, &gbc->remap_list) {
+ remap = list_entry(j, struct gpio_remap, list);
+ list_del(j);
+ kfree(remap);
+ }
+ kfree(gbc);
+ }
+
+ kfree(block->gpio);
+ kfree(block);
+}
+EXPORT_SYMBOL_GPL(gpio_block_free);
+
+unsigned long gpio_block_get(const struct gpio_block *block, unsigned long mask)
+{
+ struct gpio_block_chip *gbc;
+ unsigned long values = 0;
+
+ list_for_each_entry(gbc, &block->gbc_list, list) {
+ struct gpio_remap *remap;
+ int i;
+ unsigned long remapped = 0;
+ unsigned long remapped_mask = 0;
+
+ list_for_each_entry(remap, &gbc->remap_list, list)
+ remapped_mask |= (mask & remap->mask) << remap->offset;
+ remapped_mask &= gbc->mask;
+
+ if (!remapped_mask)
+ continue;
+
+ if (gbc->gc->get_block)
+ remapped = gbc->gc->get_block(gbc->gc, remapped_mask);
+ else
+ /* emulate */
+ for_each_set_bit(i, &remapped_mask, BITS_PER_LONG)
+ remapped |= gbc->gc->get(gbc->gc,
+ gbc->gc->base + i) << i;
+
+ list_for_each_entry(remap, &gbc->remap_list, list)
+ values |= (remapped >> remap->offset) & remap->mask;
+ }
+
+ return values;
+}
+EXPORT_SYMBOL_GPL(gpio_block_get);
+
+void gpio_block_set(struct gpio_block *block, unsigned long mask,
+ unsigned long values)
+{
+ struct gpio_block_chip *gbc;
+
+ list_for_each_entry(gbc, &block->gbc_list, list) {
+ struct gpio_remap *remap;
+ int i;
+ unsigned long remapped = 0;
+ unsigned long remapped_mask = 0;
+
+ list_for_each_entry(remap, &gbc->remap_list, list) {
+ remapped |= (values & remap->mask) << remap->offset;
+ remapped_mask |= (mask & remap->mask) << remap->offset;
+ }
+ remapped_mask &= gbc->mask;
+
+ if (!remapped_mask)
+ continue;
+
+ if (gbc->gc->set_block)
+ gbc->gc->set_block(gbc->gc, remapped_mask, remapped);
+ else
+ /* emulate */
+ for_each_set_bit(i, &remapped_mask, BITS_PER_LONG)
+ gbc->gc->set(gbc->gc, gbc->gc->base + i,
+ (remapped >> i) & 1);
+ }
+}
+EXPORT_SYMBOL_GPL(gpio_block_set);
+
+struct gpio_block *gpio_block_find_by_name(const char *name)
+{
+ struct gpio_block *i;
+
+ list_for_each_entry(i, &gpio_block_list, list)
+ if (!strcmp(i->name, name))
+ return i;
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(gpio_block_find_by_name);
+
+int gpio_block_register(struct gpio_block *block)
+{
+ if (gpio_block_find_by_name(block->name))
+ return -EBUSY;
+
+ list_add(&block->list, &gpio_block_list);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gpio_block_register);
+
+void gpio_block_unregister(struct gpio_block *block)
+{
+ struct gpio_block *i;
+
+ list_for_each_entry(i, &gpio_block_list, list)
+ if (i == block) {
+ list_del(&i->list);
+ break;
+ }
+}
+EXPORT_SYMBOL_GPL(gpio_block_unregister);
+
/**
* __gpio_cansleep() - report whether gpio value access will sleep
* @gpio: gpio in question
--- linux-2.6.orig/include/asm-generic/gpio.h
+++ linux-2.6/include/asm-generic/gpio.h
@@ -43,6 +43,7 @@ static inline bool gpio_is_valid(int num
struct device;
struct gpio;
+struct gpio_block;
struct seq_file;
struct module;
struct device_node;
@@ -105,6 +106,8 @@ struct gpio_chip {
unsigned offset);
int (*get)(struct gpio_chip *chip,
unsigned offset);
+ unsigned long (*get_block)(struct gpio_chip *chip,
+ unsigned long mask);
int (*direction_output)(struct gpio_chip *chip,
unsigned offset, int value);
int (*set_debounce)(struct gpio_chip *chip,
@@ -112,6 +115,9 @@ struct gpio_chip {
void (*set)(struct gpio_chip *chip,
unsigned offset, int value);
+ void (*set_block)(struct gpio_chip *chip,
+ unsigned long mask,
+ unsigned long values);
int (*to_irq)(struct gpio_chip *chip,
unsigned offset);
@@ -171,6 +177,17 @@ extern void gpio_set_value_cansleep(unsi
extern int __gpio_get_value(unsigned gpio);
extern void __gpio_set_value(unsigned gpio, int value);
+extern struct gpio_block *gpio_block_create(unsigned *gpio, size_t size,
+ const char *name);
+extern void gpio_block_free(struct gpio_block *block);
+extern unsigned long gpio_block_get(const struct gpio_block *block,
+ unsigned long mask);
+extern void gpio_block_set(struct gpio_block *block, unsigned long mask,
+ unsigned long values);
+extern struct gpio_block *gpio_block_find_by_name(const char *name);
+extern int gpio_block_register(struct gpio_block *block);
+extern void gpio_block_unregister(struct gpio_block *block);
+
extern int __gpio_cansleep(unsigned gpio);
extern int __gpio_to_irq(unsigned gpio);
--- linux-2.6.orig/include/linux/gpio.h
+++ linux-2.6/include/linux/gpio.h
@@ -2,6 +2,8 @@
#define __LINUX_GPIO_H
#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/list.h>
/* see Documentation/gpio.txt */
@@ -39,6 +41,64 @@ struct gpio {
const char *label;
};
+/**
+ * struct gpio_remap - a structure for describing a bit mapping
+ * @mask: a bit mask, relevant for a (partial) mapping
+ * @offset: how many bits to shift to the left (negative: to the right)
+ * @list: several remappings are internally collected in a list
+ *
+ * When we are mapping bit values from one word to another (here: from GPIO
+ * block domain to GPIO driver domain) we first mask them out with mask and
+ * shift them as specified with offset. More complicated mappings are done by
+ * grouping several of those structs and adding the results together.
+ */
+struct gpio_remap {
+ unsigned long mask;
+ int offset;
+
+ struct list_head list;
+};
+
+/**
+ * struct gpio_block_chip - a structure representing chip specific data in a
+ * gpio block
+ * @gc: the chip
+ * @remap_list: list of remappings, there are several necessary if the bits
+ * are not consecutive
+ * @mask: chip specific mask, used for propagating to the driver's
+ * get_block() and set_block() functions
+ * @list: list collecting potentially multiple chips in one block
+ *
+ * This structure holds information about remapping and masking of gpios within
+ * one chip. There can be several of those in one block.
+ */
+struct gpio_block_chip {
+ struct gpio_chip *gc;
+ struct list_head remap_list;
+ unsigned long mask;
+
+ struct list_head list;
+};
+
+/**
+ * struct gpio_block - a structure describing a list of GPIOs for simultaneous
+ * operations
+ * @gbc_list: list of chips in this block, typically just one
+ * @name: the name of this block
+ * @ngpio: number of gpios in this block
+ * @gpio: list of gpios in this block
+ * @list: global list of blocks, maintained by gpiolib
+ */
+struct gpio_block {
+ struct list_head gbc_list;
+ const char *name;
+
+ int ngpio;
+ unsigned *gpio;
+
+ struct list_head list;
+};
+
#ifdef CONFIG_GENERIC_GPIO
#ifdef CONFIG_ARCH_HAVE_CUSTOM_GPIO_H
@@ -169,6 +229,43 @@ static inline void gpio_set_value(unsign
WARN_ON(1);
}
+static inline
+struct gpio_block *gpio_block_create(unsigned *gpios, size_t size,
+ const char *name)
+{
+ WARN_ON(1);
+ return NULL;
+}
+
+static inline void gpio_block_free(struct gpio_block *block)
+{
+ WARN_ON(1);
+}
+
+static inline unsigned long gpio_block_get(const struct gpio_block *block,
+ unsigned long mask)
+{
+ WARN_ON(1);
+ return 0;
+}
+
+static inline void gpio_block_set(struct gpio_block *block, unsigned long mask,
+ unsigned long values)
+{
+ WARN_ON(1);
+}
+
+static inline int gpio_block_register(struct gpio_block *block)
+{
+ WARN_ON(1);
+ return 0;
+}
+
+static inline void gpio_block_unregister(struct gpio_block *block)
+{
+ WARN_ON(1);
+}
+
static inline int gpio_cansleep(unsigned gpio)
{
/* GPIO can never have been requested or set as {in,out}put */
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH 2/6 v8] gpio: Add sysfs support to block GPIO API
2012-11-30 18:03 [PATCH 0/6 v8] gpio: Add block GPIO Roland Stigge
2012-11-30 18:03 ` [PATCH 1/6 v8] gpio: Add a block GPIO API to gpiolib Roland Stigge
@ 2012-11-30 18:03 ` Roland Stigge
2012-11-30 18:03 ` [PATCH 3/6 v8] gpio: Add userland device interface to block GPIO Roland Stigge
` (4 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Roland Stigge @ 2012-11-30 18:03 UTC (permalink / raw)
To: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr, wg
Cc: Roland Stigge
This patch adds sysfs support to the block GPIO API.
Signed-off-by: Roland Stigge <stigge@antcom.de>
---
Documentation/ABI/testing/sysfs-gpio | 20 ++
drivers/gpio/gpiolib.c | 247 +++++++++++++++++++++++++++++++++++
include/asm-generic/gpio.h | 11 +
include/linux/gpio.h | 14 +
4 files changed, 292 insertions(+)
--- linux-2.6.orig/Documentation/ABI/testing/sysfs-gpio
+++ linux-2.6/Documentation/ABI/testing/sysfs-gpio
@@ -25,3 +25,23 @@ Description:
/label ... (r/o) descriptive, not necessarily unique
/ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1)
+What: /sys/class/gpioblock/
+Date: October 2012
+KernelVersion: 3.7
+Contact: Roland Stigge <stigge@antcom.de>
+Description:
+
+ Block GPIO devices are visible in sysfs as soon as they are registered
+ (e.g. via devicetree definition). For actual I/O use, their "exported"
+ boolean attribute must be set to "1". Then, the attribute "values" is
+ created and at the same time, the GPIOs in the block are requested for
+ exclusive use by sysfs.
+
+ /sys/class/gpioblock
+ /BLOCKNAME ... for each GPIO block name
+ /ngpio ... (r/o) number of GPIOs in this group
+ /exported ... sysfs export state of this group (0, 1)
+ /value ... current value as 32 or 64 bit integer in hex
+ (only available if /exported is 1)
+ /mask ... current mask as 32 or 64 bit integer in hex
+ (only available if /exported is 1)
--- linux-2.6.orig/drivers/gpio/gpiolib.c
+++ linux-2.6/drivers/gpio/gpiolib.c
@@ -984,6 +984,238 @@ static void gpiochip_unexport(struct gpi
chip->label, status);
}
+static ssize_t gpio_block_ngpio_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_block *block = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", block->ngpio);
+}
+
+static ssize_t gpio_block_value_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_block *block = dev_get_drvdata(dev);
+
+ return sprintf(buf, sizeof(unsigned long) == 4 ? "0x%08lx\n" :
+ "0x%016lx\n", gpio_block_get(block, ~0));
+}
+
+static ssize_t gpio_block_value_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ ssize_t status;
+ struct gpio_block *block = dev_get_drvdata(dev);
+ unsigned long value;
+
+ status = kstrtoul(buf, 0, &value);
+ if (status == 0) {
+ mutex_lock(&sysfs_lock);
+ if (gpio_block_is_output(block)) {
+ gpio_block_set(block, ~0, value);
+ status = size;
+ } else {
+ status = -EPERM;
+ }
+ mutex_unlock(&sysfs_lock);
+ }
+ return status;
+}
+
+static struct device_attribute
+dev_attr_block_value = __ATTR(value, S_IWUSR | S_IRUGO, gpio_block_value_show,
+ gpio_block_value_store);
+
+static ssize_t gpio_block_mask_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_block *block = dev_get_drvdata(dev);
+
+ return sprintf(buf, sizeof(unsigned long) == 4 ? "0x%08lx\n" :
+ "0x%016lx\n", block->cur_mask);
+}
+
+static ssize_t gpio_block_mask_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ ssize_t status;
+ struct gpio_block *block = dev_get_drvdata(dev);
+ unsigned long mask;
+
+ status = kstrtoul(buf, 0, &mask);
+ if (status == 0)
+ block->cur_mask = mask;
+ return status;
+}
+
+static struct device_attribute
+dev_attr_block_mask = __ATTR(mask, S_IWUSR | S_IRUGO, gpio_block_mask_show,
+ gpio_block_mask_store);
+
+static struct class gpio_block_class;
+
+static int gpio_block_value_is_exported(struct gpio_block *block)
+{
+ struct device *dev;
+ struct sysfs_dirent *sd = NULL;
+
+ mutex_lock(&sysfs_lock);
+ dev = class_find_device(&gpio_block_class, NULL, block, match_export);
+ if (!dev)
+ goto out;
+
+ sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value");
+
+out:
+ mutex_unlock(&sysfs_lock);
+ return !!sd;
+}
+
+static ssize_t gpio_block_exported_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct gpio_block *block = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", gpio_block_value_is_exported(block));
+}
+
+static int gpio_block_value_export(struct gpio_block *block)
+{
+ struct device *dev;
+ int status;
+ int i;
+
+ mutex_lock(&sysfs_lock);
+
+ for (i = 0; i < block->ngpio; i++) {
+ status = gpio_request(block->gpio[i], "sysfs");
+ if (status)
+ goto out1;
+ }
+
+ dev = class_find_device(&gpio_block_class, NULL, block, match_export);
+ if (!dev) {
+ status = -ENODEV;
+ goto out1;
+ }
+
+ status = device_create_file(dev, &dev_attr_block_value);
+ if (status)
+ goto out1;
+
+ status = device_create_file(dev, &dev_attr_block_mask);
+ if (status)
+ goto out2;
+
+ mutex_unlock(&sysfs_lock);
+ return 0;
+
+out2:
+ device_remove_file(dev, &dev_attr_block_value);
+out1:
+ while (--i >= 0)
+ gpio_free(block->gpio[i]);
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static int gpio_block_value_unexport(struct gpio_block *block)
+{
+ struct device *dev;
+ int i;
+
+ dev = class_find_device(&gpio_block_class, NULL, block, match_export);
+ if (!dev)
+ return -ENODEV;
+
+ for (i = 0; i < block->ngpio; i++)
+ gpio_free(block->gpio[i]);
+
+ device_remove_file(dev, &dev_attr_block_value);
+ device_remove_file(dev, &dev_attr_block_mask);
+
+ return 0;
+}
+
+static ssize_t gpio_block_exported_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ long value;
+ int status;
+ struct gpio_block *block = dev_get_drvdata(dev);
+ int exported = gpio_block_value_is_exported(block);
+
+ status = kstrtoul(buf, 0, &value);
+ if (status < 0)
+ goto err;
+
+ if (value != exported) {
+ if (value)
+ status = gpio_block_value_export(block);
+ else
+ status = gpio_block_value_unexport(block);
+ if (!status)
+ status = size;
+ } else {
+ status = size;
+ }
+err:
+ return status;
+}
+
+static struct device_attribute gpio_block_attrs[] = {
+ __ATTR(exported, S_IWUSR | S_IRUGO, gpio_block_exported_show,
+ gpio_block_exported_store),
+ __ATTR(ngpio, S_IRUGO, gpio_block_ngpio_show, NULL),
+ __ATTR_NULL,
+};
+
+static struct class gpio_block_class = {
+ .name = "gpioblock",
+ .owner = THIS_MODULE,
+
+ .dev_attrs = gpio_block_attrs,
+};
+
+int gpio_block_export(struct gpio_block *block)
+{
+ int status = 0;
+ struct device *dev;
+
+ /* can't export until sysfs is available ... */
+ if (!gpio_block_class.p) {
+ pr_debug("%s: called too early!\n", __func__);
+ return -ENOENT;
+ }
+
+ mutex_lock(&sysfs_lock);
+ dev = device_create(&gpio_block_class, NULL, MKDEV(0, 0), block,
+ block->name);
+ if (IS_ERR(dev))
+ status = PTR_ERR(dev);
+ mutex_unlock(&sysfs_lock);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_block_export);
+
+void gpio_block_unexport(struct gpio_block *block)
+{
+ struct device *dev;
+
+ mutex_lock(&sysfs_lock);
+ dev = class_find_device(&gpio_block_class, NULL, block, match_export);
+ if (dev)
+ device_unregister(dev);
+ mutex_unlock(&sysfs_lock);
+}
+EXPORT_SYMBOL_GPL(gpio_block_unexport);
+
static int __init gpiolib_sysfs_init(void)
{
int status;
@@ -994,6 +1226,10 @@ static int __init gpiolib_sysfs_init(voi
if (status < 0)
return status;
+ status = class_register(&gpio_block_class);
+ if (status < 0)
+ return status;
+
/* Scan and register the gpio_chips which registered very
* early (e.g. before the class_register above was called).
*
@@ -1724,6 +1960,7 @@ struct gpio_block *gpio_block_create(uns
block->name = name;
block->ngpio = size;
+ block->cur_mask = ~0;
INIT_LIST_HEAD(&block->gbc_list);
block->gpio = kzalloc(sizeof(*block->gpio) * size, GFP_KERNEL);
if (!block->gpio)
@@ -1886,12 +2123,21 @@ EXPORT_SYMBOL_GPL(gpio_block_find_by_nam
int gpio_block_register(struct gpio_block *block)
{
+ int ret;
+
if (gpio_block_find_by_name(block->name))
return -EBUSY;
list_add(&block->list, &gpio_block_list);
+ ret = gpio_block_export(block);
+ if (ret)
+ goto err1;
+
return 0;
+err1:
+ list_del(&block->list);
+ return ret;
}
EXPORT_SYMBOL_GPL(gpio_block_register);
@@ -1902,6 +2148,7 @@ void gpio_block_unregister(struct gpio_b
list_for_each_entry(i, &gpio_block_list, list)
if (i == block) {
list_del(&i->list);
+ gpio_block_unexport(block);
break;
}
}
--- linux-2.6.orig/include/asm-generic/gpio.h
+++ linux-2.6/include/asm-generic/gpio.h
@@ -213,6 +213,8 @@ extern int gpio_export_link(struct devic
unsigned gpio);
extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
extern void gpio_unexport(unsigned gpio);
+extern int gpio_block_export(struct gpio_block *block);
+extern void gpio_block_unexport(struct gpio_block *block);
#endif /* CONFIG_GPIO_SYSFS */
@@ -272,6 +274,15 @@ static inline int gpio_sysfs_set_active_
static inline void gpio_unexport(unsigned gpio)
{
}
+
+static inline int gpio_block_export(struct gpio_block *block)
+{
+ return -ENOSYS;
+}
+
+static inline void gpio_block_unexport(struct gpio_block *block)
+{
+}
#endif /* CONFIG_GPIO_SYSFS */
#endif /* _ASM_GENERIC_GPIO_H */
--- linux-2.6.orig/include/linux/gpio.h
+++ linux-2.6/include/linux/gpio.h
@@ -97,6 +97,7 @@ struct gpio_block {
unsigned *gpio;
struct list_head list;
+ unsigned long cur_mask;
};
#ifdef CONFIG_GENERIC_GPIO
@@ -314,6 +315,19 @@ static inline void gpio_unexport(unsigne
WARN_ON(1);
}
+static inline int gpio_block_export(struct gpio_block *block)
+{
+ /* GPIO block can never have been requested or set as {in,out}put */
+ WARN_ON(1);
+ return -EINVAL;
+}
+
+static inline void gpio_block_unexport(struct gpio_block *block)
+{
+ /* GPIO block can never have been exported */
+ WARN_ON(1);
+}
+
static inline int gpio_to_irq(unsigned gpio)
{
/* GPIO can never have been requested or set as input */
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH 3/6 v8] gpio: Add userland device interface to block GPIO
2012-11-30 18:03 [PATCH 0/6 v8] gpio: Add block GPIO Roland Stigge
2012-11-30 18:03 ` [PATCH 1/6 v8] gpio: Add a block GPIO API to gpiolib Roland Stigge
2012-11-30 18:03 ` [PATCH 2/6 v8] gpio: Add sysfs support to block GPIO API Roland Stigge
@ 2012-11-30 18:03 ` Roland Stigge
2012-11-30 18:03 ` [PATCH 4/6 v8] gpiolib: Fix default attributes for class Roland Stigge
` (3 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Roland Stigge @ 2012-11-30 18:03 UTC (permalink / raw)
To: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr, wg
Cc: Roland Stigge
This patch adds a character device interface to the block GPIO system.
Signed-off-by: Roland Stigge <stigge@antcom.de>
---
Documentation/ABI/testing/dev-gpioblock | 25 ++++++
drivers/gpio/gpiolib.c | 121 +++++++++++++++++++++++++++++++-
include/linux/gpio.h | 4 +
3 files changed, 147 insertions(+), 3 deletions(-)
--- /dev/null
+++ linux-2.6/Documentation/ABI/testing/dev-gpioblock
@@ -0,0 +1,25 @@
+What: /dev/<gpioblock>
+Date: Nov 2012
+KernelVersion: 3.7
+Contact: Roland Stigge <stigge@antcom.de>
+Description: The /dev/<gpioblock> character device node provides userspace
+ access to GPIO blocks, named exactly as the block, e.g.
+ /dev/block0.
+
+ Reading:
+ When reading sizeof(unsigned long) bytes from the device, the
+ current state of the block, masked by the current mask (see
+ below) can be obtained as a word.
+
+ Writing:
+ By writing sizeof(unsigned long) bytes to the device, the
+ current state of the block can be set. This operation is
+ masked by the current mask (see below).
+
+ Setting the mask (default: all bits set):
+ By doing an ioctl(fd, 0, &mask) with an unsigned long mask, the
+ current mask for read and write operations on this gpio block
+ can be set.
+
+ See also Documentation/gpio.txt for an explanation of block
+ GPIO.
--- linux-2.6.orig/drivers/gpio/gpiolib.c
+++ linux-2.6/drivers/gpio/gpiolib.c
@@ -11,6 +11,7 @@
#include <linux/of_gpio.h>
#include <linux/idr.h>
#include <linux/slab.h>
+#include <linux/uaccess.h>
#define CREATE_TRACE_POINTS
#include <trace/events/gpio.h>
@@ -193,12 +194,13 @@ err:
return ret;
}
-static bool gpio_block_is_output(struct gpio_block *block)
+static bool gpio_block_is_output(struct gpio_block *block, unsigned long mask)
{
int i;
for (i = 0; i < block->ngpio; i++)
- if (!test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags))
+ if ((mask & BIT(i)) &&
+ !test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags))
return false;
return true;
}
@@ -1012,7 +1014,7 @@ static ssize_t gpio_block_value_store(st
status = kstrtoul(buf, 0, &value);
if (status == 0) {
mutex_lock(&sysfs_lock);
- if (gpio_block_is_output(block)) {
+ if (gpio_block_is_output(block, ~0)) {
gpio_block_set(block, ~0, value);
status = size;
} else {
@@ -2121,6 +2123,105 @@ struct gpio_block *gpio_block_find_by_na
}
EXPORT_SYMBOL_GPL(gpio_block_find_by_name);
+static struct gpio_block *gpio_block_find_by_minor(int minor)
+{
+ struct gpio_block *i;
+
+ list_for_each_entry(i, &gpio_block_list, list)
+ if (i->miscdev.minor == minor)
+ return i;
+ return NULL;
+}
+
+static int gpio_block_fop_open(struct inode *in, struct file *f)
+{
+ int i;
+ struct gpio_block *block = gpio_block_find_by_minor(MINOR(in->i_rdev));
+
+ if (!block)
+ return -ENOENT;
+
+ for (i = 0; i < block->ngpio; i++) {
+ int status = gpio_request(block->gpio[i], "gpioblock dev");
+
+ if (status)
+ return -EBUSY;
+ }
+
+ f->private_data = block;
+
+ return 0;
+}
+
+static int gpio_block_fop_release(struct inode *in, struct file *f)
+{
+ int i;
+ struct gpio_block *block = (struct gpio_block *)f->private_data;
+
+ for (i = 0; i < block->ngpio; i++)
+ gpio_free(block->gpio[i]);
+
+ return 0;
+}
+
+static ssize_t gpio_block_fop_read(struct file *f, char __user *buf, size_t n,
+ loff_t *offset)
+{
+ struct gpio_block *block = (struct gpio_block *)f->private_data;
+ int err;
+
+ if (n >= sizeof(unsigned long)) {
+ unsigned long values = gpio_block_get(block, block->cur_mask);
+
+ err = put_user(values, buf);
+ if (err)
+ return err;
+
+ return sizeof(unsigned long);
+ }
+ return 0;
+}
+static ssize_t gpio_block_fop_write(struct file *f, const char __user *buf,
+ size_t n, loff_t *offset)
+{
+ struct gpio_block *block = (struct gpio_block *)f->private_data;
+ int err;
+
+ if (n >= sizeof(unsigned long)) {
+ unsigned long values;
+
+ err = get_user(values, buf);
+ if (err)
+ return err;
+ if (gpio_block_is_output(block, block->cur_mask))
+ gpio_block_set(block, block->cur_mask, values);
+ else
+ return -EPERM;
+ return sizeof(unsigned long);
+ }
+ return 0;
+}
+
+static long gpio_block_fop_ioctl(struct file *f, unsigned int cmd,
+ unsigned long arg)
+{
+ struct gpio_block *block = (struct gpio_block *)f->private_data;
+ unsigned long __user *x = (unsigned long __user *)arg;
+
+ if (cmd == 0)
+ return get_user(block->cur_mask, x);
+
+ return -EINVAL;
+}
+
+static const struct file_operations gpio_block_fops = {
+ .open = gpio_block_fop_open,
+ .release = gpio_block_fop_release,
+ .read = gpio_block_fop_read,
+ .write = gpio_block_fop_write,
+ .unlocked_ioctl = gpio_block_fop_ioctl,
+};
+
int gpio_block_register(struct gpio_block *block)
{
int ret;
@@ -2134,9 +2235,22 @@ int gpio_block_register(struct gpio_bloc
if (ret)
goto err1;
+ block->miscdev.name = block->name;
+ block->miscdev.nodename = block->name;
+ block->miscdev.minor = MISC_DYNAMIC_MINOR;
+ block->miscdev.fops = &gpio_block_fops;
+ block->miscdev.mode = S_IWUSR | S_IRUGO;
+
+ ret = misc_register(&block->miscdev);
+ if (ret)
+ goto err2;
+
return 0;
+err2:
+ gpio_block_unexport(block);
err1:
list_del(&block->list);
+
return ret;
}
EXPORT_SYMBOL_GPL(gpio_block_register);
@@ -2149,6 +2263,7 @@ void gpio_block_unregister(struct gpio_b
if (i == block) {
list_del(&i->list);
gpio_block_unexport(block);
+ misc_deregister(&block->miscdev);
break;
}
}
--- linux-2.6.orig/include/linux/gpio.h
+++ linux-2.6/include/linux/gpio.h
@@ -4,6 +4,7 @@
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/list.h>
+#include <linux/miscdevice.h>
/* see Documentation/gpio.txt */
@@ -88,6 +89,8 @@ struct gpio_block_chip {
* @ngpio: number of gpios in this block
* @gpio: list of gpios in this block
* @list: global list of blocks, maintained by gpiolib
+ * @miscdev: userspace API / device
+ * @cur_mask: currently used gpio mask used by userspace API
*/
struct gpio_block {
struct list_head gbc_list;
@@ -98,6 +101,7 @@ struct gpio_block {
struct list_head list;
unsigned long cur_mask;
+ struct miscdevice miscdev;
};
#ifdef CONFIG_GENERIC_GPIO
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH 4/6 v8] gpiolib: Fix default attributes for class
2012-11-30 18:03 [PATCH 0/6 v8] gpio: Add block GPIO Roland Stigge
` (2 preceding siblings ...)
2012-11-30 18:03 ` [PATCH 3/6 v8] gpio: Add userland device interface to block GPIO Roland Stigge
@ 2012-11-30 18:03 ` Roland Stigge
2012-11-30 18:03 ` [PATCH 5/6 v8] gpio: Add device tree support to block GPIO API Roland Stigge
` (2 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Roland Stigge @ 2012-11-30 18:03 UTC (permalink / raw)
To: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr, wg
Cc: Roland Stigge
There is a race condition between creating a gpio or gpiochip device and adding
default attributes. This patch fixes this by defining the default attributes as
dev_attrs of the class. For this, it was necessary to create a separate
gpiochip_class besides gpio_class.
Signed-off-by: Roland Stigge <stigge@antcom.de>
---
Documentation/ABI/testing/sysfs-gpio | 11 ++++
drivers/gpio/gpiolib.c | 79 +++++++++++++++--------------------
2 files changed, 45 insertions(+), 45 deletions(-)
--- linux-2.6.orig/Documentation/ABI/testing/sysfs-gpio
+++ linux-2.6/Documentation/ABI/testing/sysfs-gpio
@@ -20,6 +20,17 @@ Description:
/value ... always readable, writes fail for input GPIOs
/direction ... r/w as: in, out (default low); write: high, low
/edge ... r/w as: none, falling, rising, both
+
+What: /sys/class/gpiochip/
+Date: October 2012
+KernelVersion: 3.7
+Contact: Roland Stigge <stigge@antcom.de>
+Description:
+
+ Each gpiochip is represented by a separate device having the following
+ attributes:
+
+ /sys/class/gpiochip
/gpiochipN ... for each gpiochip; #N is its first GPIO
/base ... (r/o) same as N
/label ... (r/o) descriptive, not necessarily unique
--- linux-2.6.orig/drivers/gpio/gpiolib.c
+++ linux-2.6/drivers/gpio/gpiolib.c
@@ -333,9 +333,6 @@ static ssize_t gpio_value_store(struct d
return status;
}
-static const DEVICE_ATTR(value, 0644,
- gpio_value_show, gpio_value_store);
-
static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
{
struct sysfs_dirent *value_sd = priv;
@@ -556,19 +553,6 @@ static ssize_t gpio_active_low_store(str
return status ? : size;
}
-static const DEVICE_ATTR(active_low, 0644,
- gpio_active_low_show, gpio_active_low_store);
-
-static const struct attribute *gpio_attrs[] = {
- &dev_attr_value.attr,
- &dev_attr_active_low.attr,
- NULL,
-};
-
-static const struct attribute_group gpio_attr_group = {
- .attrs = (struct attribute **) gpio_attrs,
-};
-
/*
* /sys/class/gpio/gpiochipN/
* /base ... matching gpio_chip.base (N)
@@ -583,7 +567,6 @@ static ssize_t chip_base_show(struct dev
return sprintf(buf, "%d\n", chip->base);
}
-static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
static ssize_t chip_label_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -592,7 +575,6 @@ static ssize_t chip_label_show(struct de
return sprintf(buf, "%s\n", chip->label ? : "");
}
-static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
static ssize_t chip_ngpio_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -601,18 +583,6 @@ static ssize_t chip_ngpio_show(struct de
return sprintf(buf, "%u\n", chip->ngpio);
}
-static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
-
-static const struct attribute *gpiochip_attrs[] = {
- &dev_attr_base.attr,
- &dev_attr_label.attr,
- &dev_attr_ngpio.attr,
- NULL,
-};
-
-static const struct attribute_group gpiochip_attr_group = {
- .attrs = (struct attribute **) gpiochip_attrs,
-};
/*
* /sys/class/gpio/export ... write-only
@@ -691,11 +661,32 @@ static struct class_attribute gpio_class
__ATTR_NULL,
};
+static struct device_attribute gpio_attrs[] = {
+ __ATTR(active_low, 0644, gpio_active_low_show, gpio_active_low_store),
+ __ATTR(value, 0644, gpio_value_show, gpio_value_store),
+ __ATTR_NULL,
+};
+
static struct class gpio_class = {
.name = "gpio",
.owner = THIS_MODULE,
- .class_attrs = gpio_class_attrs,
+ .class_attrs = gpio_class_attrs,
+ .dev_attrs = gpio_attrs,
+};
+
+static struct device_attribute gpiochip_attrs[] = {
+ __ATTR(label, 0444, chip_label_show, NULL),
+ __ATTR(base, 0444, chip_base_show, NULL),
+ __ATTR(ngpio, 0444, chip_ngpio_show, NULL),
+ __ATTR_NULL,
+};
+
+static struct class gpiochip_class = {
+ .name = "gpiochip",
+ .owner = THIS_MODULE,
+
+ .dev_attrs = gpiochip_attrs,
};
@@ -752,10 +743,7 @@ int gpio_export(unsigned gpio, bool dire
dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
desc, ioname ? ioname : "gpio%u", gpio);
if (!IS_ERR(dev)) {
- status = sysfs_create_group(&dev->kobj,
- &gpio_attr_group);
-
- if (!status && direction_may_change)
+ if (direction_may_change)
status = device_create_file(dev,
&dev_attr_direction);
@@ -925,25 +913,22 @@ EXPORT_SYMBOL_GPL(gpio_unexport);
static int gpiochip_export(struct gpio_chip *chip)
{
- int status;
+ int status = 0;
struct device *dev;
/* Many systems register gpio chips for SOC support very early,
* before driver model support is available. In those cases we
* export this later, in gpiolib_sysfs_init() ... here we just
- * verify that _some_ field of gpio_class got initialized.
+ * verify that _some_ field of gpiochip_class got initialized.
*/
- if (!gpio_class.p)
+ if (!gpiochip_class.p)
return 0;
/* use chip->base for the ID; it's already known to be unique */
mutex_lock(&sysfs_lock);
- dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
- "gpiochip%d", chip->base);
- if (!IS_ERR(dev)) {
- status = sysfs_create_group(&dev->kobj,
- &gpiochip_attr_group);
- } else
+ dev = device_create(&gpiochip_class, chip->dev, MKDEV(0, 0), chip,
+ "gpiochip%d", chip->base);
+ if (IS_ERR(dev))
status = PTR_ERR(dev);
chip->exported = (status == 0);
mutex_unlock(&sysfs_lock);
@@ -971,7 +956,7 @@ static void gpiochip_unexport(struct gpi
struct device *dev;
mutex_lock(&sysfs_lock);
- dev = class_find_device(&gpio_class, NULL, chip, match_export);
+ dev = class_find_device(&gpiochip_class, NULL, chip, match_export);
if (dev) {
put_device(dev);
device_unregister(dev);
@@ -1228,6 +1213,10 @@ static int __init gpiolib_sysfs_init(voi
if (status < 0)
return status;
+ status = class_register(&gpiochip_class);
+ if (status < 0)
+ return status;
+
status = class_register(&gpio_block_class);
if (status < 0)
return status;
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH 5/6 v8] gpio: Add device tree support to block GPIO API
2012-11-30 18:03 [PATCH 0/6 v8] gpio: Add block GPIO Roland Stigge
` (3 preceding siblings ...)
2012-11-30 18:03 ` [PATCH 4/6 v8] gpiolib: Fix default attributes for class Roland Stigge
@ 2012-11-30 18:03 ` Roland Stigge
2012-11-30 18:03 ` [PATCH 6/6 v8] gpio: Add block gpio to several gpio drivers Roland Stigge
2012-12-03 9:17 ` [PATCH 0/6 v8] gpio: Add block GPIO Wolfgang Grandegger
6 siblings, 0 replies; 11+ messages in thread
From: Roland Stigge @ 2012-11-30 18:03 UTC (permalink / raw)
To: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr, wg
Cc: Roland Stigge
This patch adds device tree support to the block GPIO API.
Signed-off-by: Roland Stigge <stigge@antcom.de>
---
Documentation/devicetree/bindings/gpio/gpio-block.txt | 36 +++++++
drivers/gpio/Makefile | 1
drivers/gpio/gpioblock-of.c | 84 ++++++++++++++++++
3 files changed, 121 insertions(+)
--- /dev/null
+++ linux-2.6/Documentation/devicetree/bindings/gpio/gpio-block.txt
@@ -0,0 +1,36 @@
+Block GPIO definition
+=====================
+
+This binding specifies arbitrary blocks of gpios, combining gpios from one or
+more GPIO controllers together, to form a word for r/w access.
+
+Required property:
+- compatible: must be "linux,gpio-block"
+
+Required subnodes:
+- the name will be the registered name of the block
+- property "gpios" is a list of gpios for the respective block
+
+Example:
+
+ blockgpio {
+ compatible = "linux,gpio-block";
+
+ block0 {
+ gpios = <&gpio 3 0 0>,
+ <&gpio 3 1 0>;
+ };
+ block1 {
+ gpios = <&gpio 4 1 0>,
+ <&gpio 4 3 0>,
+ <&gpio 4 2 0>,
+ <&gpio 4 4 0>,
+ <&gpio 4 5 0>,
+ <&gpio 4 6 0>,
+ <&gpio 4 7 0>,
+ <&gpio 4 8 0>,
+ <&gpio 4 9 0>,
+ <&gpio 4 10 0>,
+ <&gpio 4 19 0>;
+ };
+ };
--- linux-2.6.orig/drivers/gpio/Makefile
+++ linux-2.6/drivers/gpio/Makefile
@@ -4,6 +4,7 @@ ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
obj-$(CONFIG_GPIOLIB) += gpiolib.o devres.o
obj-$(CONFIG_OF_GPIO) += gpiolib-of.o
+obj-$(CONFIG_OF_GPIO) += gpioblock-of.o
# Device drivers. Generally keep list sorted alphabetically
obj-$(CONFIG_GPIO_GENERIC) += gpio-generic.o
--- /dev/null
+++ linux-2.6/drivers/gpio/gpioblock-of.c
@@ -0,0 +1,84 @@
+/*
+ * OF implementation for Block GPIO
+ *
+ * Copyright (C) 2012 Roland Stigge <stigge@antcom.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+
+static int __devinit gpioblock_of_probe(struct platform_device *pdev)
+{
+ struct device_node *block;
+ unsigned *gpios;
+ int ngpio;
+ int ret;
+ struct gpio_block *gb;
+
+ for_each_available_child_of_node(pdev->dev.of_node, block) {
+ int i;
+
+ ngpio = of_gpio_count(block);
+ gpios = kzalloc(ngpio * sizeof(*gpios), GFP_KERNEL);
+ if (!gpios)
+ return -ENOMEM;
+ for (i = 0; i < ngpio; i++) {
+ ret = of_get_gpio(block, i);
+ if (ret < 0)
+ return ret; /* expect -EPROBE_DEFER */
+ gpios[i] = ret;
+ }
+ gb = gpio_block_create(gpios, ngpio, block->name);
+ if (IS_ERR(gb)) {
+ dev_err(&pdev->dev,
+ "Error creating GPIO block from device tree\n");
+ return PTR_ERR(gb);
+ }
+ ret = gpio_block_register(gb);
+ if (ret < 0) {
+ gpio_block_free(gb);
+ return ret;
+ }
+ kfree(gpios);
+ dev_info(&pdev->dev, "Registered gpio block %s: %d gpios\n",
+ block->name, ngpio);
+ }
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id gpioblock_of_match[] __devinitdata = {
+ { .compatible = "linux,gpio-block", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, gpioblock_of_match);
+#endif
+
+static struct platform_driver gpioblock_of_driver = {
+ .driver = {
+ .name = "gpio-block",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(gpioblock_of_match),
+
+ },
+ .probe = gpioblock_of_probe,
+};
+
+module_platform_driver(gpioblock_of_driver);
+
+MODULE_DESCRIPTION("GPIO Block driver");
+MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpioblock-of");
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH 6/6 v8] gpio: Add block gpio to several gpio drivers
2012-11-30 18:03 [PATCH 0/6 v8] gpio: Add block GPIO Roland Stigge
` (4 preceding siblings ...)
2012-11-30 18:03 ` [PATCH 5/6 v8] gpio: Add device tree support to block GPIO API Roland Stigge
@ 2012-11-30 18:03 ` Roland Stigge
2012-12-03 9:17 ` [PATCH 0/6 v8] gpio: Add block GPIO Wolfgang Grandegger
6 siblings, 0 replies; 11+ messages in thread
From: Roland Stigge @ 2012-11-30 18:03 UTC (permalink / raw)
To: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr, wg
Cc: Roland Stigge
This patch adds block GPIO support to several gpio drivers.
Signed-off-by: Roland Stigge <stigge@antcom.de>
---
drivers/gpio/gpio-em.c | 23 ++++++++++++
drivers/gpio/gpio-generic.c | 56 ++++++++++++++++++++++++++++++
drivers/gpio/gpio-lpc32xx.c | 82 ++++++++++++++++++++++++++++++++++++++++++++
drivers/gpio/gpio-max730x.c | 61 ++++++++++++++++++++++++++++++++
drivers/gpio/gpio-max732x.c | 59 +++++++++++++++++++++++++++++++
drivers/gpio/gpio-pca953x.c | 64 ++++++++++++++++++++++++++++++++++
drivers/gpio/gpio-pcf857x.c | 24 ++++++++++++
drivers/gpio/gpio-pch.c | 27 ++++++++++++++
drivers/gpio/gpio-pl061.c | 17 +++++++++
drivers/gpio/gpio-twl6040.c | 32 +++++++++++++++++
drivers/gpio/gpio-ucb1400.c | 23 ++++++++++++
drivers/gpio/gpio-vt8500.c | 24 ++++++++++++
drivers/gpio/gpio-xilinx.c | 44 +++++++++++++++++++++++
13 files changed, 536 insertions(+)
--- linux-2.6.orig/drivers/gpio/gpio-em.c
+++ linux-2.6/drivers/gpio/gpio-em.c
@@ -203,6 +203,27 @@ static void em_gio_set(struct gpio_chip
__em_gio_set(chip, GIO_OH, offset - 16, value);
}
+static unsigned long em_gio_get_block(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ return (int)(em_gio_read(gpio_to_priv(chip), GIO_I) & mask);
+}
+
+static void em_gio_set_block(struct gpio_chip *chip, unsigned long mask,
+ unsigned long values)
+{
+ unsigned long mask_ol = mask & 0xFFFF;
+ unsigned long mask_oh = mask >> 16;
+
+ unsigned long values_ol = values & mask_ol;
+ unsigned long values_oh = (values >> 16) & mask_oh;
+
+ em_gio_write(gpio_to_priv(chip), GIO_OL,
+ mask_ol << 16 | values_ol);
+ em_gio_write(gpio_to_priv(chip), GIO_OH,
+ mask_oh << 16 | values_oh);
+}
+
static int em_gio_direction_output(struct gpio_chip *chip, unsigned offset,
int value)
{
@@ -317,8 +338,10 @@ static int __devinit em_gio_probe(struct
gpio_chip = &p->gpio_chip;
gpio_chip->direction_input = em_gio_direction_input;
gpio_chip->get = em_gio_get;
+ gpio_chip->get_block = em_gio_get_block;
gpio_chip->direction_output = em_gio_direction_output;
gpio_chip->set = em_gio_set;
+ gpio_chip->set_block = em_gio_set_block;
gpio_chip->to_irq = em_gio_to_irq;
gpio_chip->label = name;
gpio_chip->owner = THIS_MODULE;
--- linux-2.6.orig/drivers/gpio/gpio-generic.c
+++ linux-2.6/drivers/gpio/gpio-generic.c
@@ -122,6 +122,13 @@ static int bgpio_get(struct gpio_chip *g
return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);
}
+static unsigned long bgpio_get_block(struct gpio_chip *gc, unsigned long mask)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+ return bgc->read_reg(bgc->reg_dat) & mask;
+}
+
static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
struct bgpio_chip *bgc = to_bgpio_chip(gc);
@@ -170,6 +177,51 @@ static void bgpio_set_set(struct gpio_ch
spin_unlock_irqrestore(&bgc->lock, flags);
}
+static void bgpio_set_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->data &= ~mask;
+ bgc->data |= values & mask;
+
+ bgc->write_reg(bgc->reg_dat, bgc->data);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void bgpio_set_with_clear_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long set_bits = values & mask;
+ unsigned long clr_bits = ~values & mask;
+
+ if (set_bits)
+ bgc->write_reg(bgc->reg_set, set_bits);
+ if (clr_bits)
+ bgc->write_reg(bgc->reg_set, clr_bits);
+}
+
+static void bgpio_set_set_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->data &= ~mask;
+ bgc->data |= values & mask;
+
+ bgc->write_reg(bgc->reg_set, bgc->data);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
{
return 0;
@@ -317,14 +369,18 @@ static int bgpio_setup_io(struct bgpio_c
bgc->reg_set = set;
bgc->reg_clr = clr;
bgc->gc.set = bgpio_set_with_clear;
+ bgc->gc.set_block = bgpio_set_with_clear_block;
} else if (set && !clr) {
bgc->reg_set = set;
bgc->gc.set = bgpio_set_set;
+ bgc->gc.set_block = bgpio_set_set_block;
} else {
bgc->gc.set = bgpio_set;
+ bgc->gc.set_block = bgpio_set_block;
}
bgc->gc.get = bgpio_get;
+ bgc->gc.get_block = bgpio_get_block;
return 0;
}
--- linux-2.6.orig/drivers/gpio/gpio-lpc32xx.c
+++ linux-2.6/drivers/gpio/gpio-lpc32xx.c
@@ -297,6 +297,22 @@ static int lpc32xx_gpio_get_value_p3(str
return __get_gpio_state_p3(group, pin);
}
+static unsigned long lpc32xx_gpio_get_block_p3(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ struct lpc32xx_gpio_chip *group = to_lpc32xx_gpio(chip);
+ u32 bits = __raw_readl(group->gpio_grp->inp_state);
+
+ /* In P3_INP_STATE, the 6 GPIOs are scattered over the register,
+ * rearranging to bits 0-5
+ */
+ bits >>= 10;
+ bits &= 0x401F;
+ bits |= (bits & 0x4000) >> 9;
+
+ return bits & mask & 0x3F;
+}
+
static int lpc32xx_gpi_get_value(struct gpio_chip *chip, unsigned pin)
{
struct lpc32xx_gpio_chip *group = to_lpc32xx_gpio(chip);
@@ -304,6 +320,15 @@ static int lpc32xx_gpi_get_value(struct
return __get_gpi_state_p3(group, pin);
}
+static unsigned long lpc32xx_gpi_get_block(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ struct lpc32xx_gpio_chip *group = to_lpc32xx_gpio(chip);
+ u32 bits = __raw_readl(group->gpio_grp->inp_state);
+
+ return bits & mask;
+}
+
static int lpc32xx_gpio_dir_output_p012(struct gpio_chip *chip, unsigned pin,
int value)
{
@@ -351,6 +376,27 @@ static void lpc32xx_gpio_set_value_p3(st
__set_gpio_level_p3(group, pin, value);
}
+static void lpc32xx_gpio_set_block_p3(struct gpio_chip *chip,
+ unsigned long mask,
+ unsigned long values)
+{
+ struct lpc32xx_gpio_chip *group = to_lpc32xx_gpio(chip);
+ u32 set_bits = values & mask;
+ u32 clr_bits = ~values & mask;
+
+ /* States of GPIO 0-5 start at bit 25 */
+ set_bits <<= 25;
+ clr_bits <<= 25;
+
+ /* Note: On LPC32xx, GPOs can only be set at once or cleared at once,
+ * but not set and cleared at once
+ */
+ if (set_bits)
+ __raw_writel(set_bits, group->gpio_grp->outp_set);
+ if (clr_bits)
+ __raw_writel(clr_bits, group->gpio_grp->outp_clr);
+}
+
static void lpc32xx_gpo_set_value(struct gpio_chip *chip, unsigned pin,
int value)
{
@@ -366,6 +412,31 @@ static int lpc32xx_gpo_get_value(struct
return __get_gpo_state_p3(group, pin);
}
+static void lpc32xx_gpo_set_block(struct gpio_chip *chip, unsigned long mask,
+ unsigned long values)
+{
+ struct lpc32xx_gpio_chip *group = to_lpc32xx_gpio(chip);
+ u32 set_bits = values & mask;
+ u32 clr_bits = ~values & mask;
+
+ /* Note: On LPC32xx, GPOs can only be set at once or cleared at once,
+ * but not set and cleared at once
+ */
+ if (set_bits)
+ __raw_writel(set_bits, group->gpio_grp->outp_set);
+ if (clr_bits)
+ __raw_writel(clr_bits, group->gpio_grp->outp_clr);
+}
+
+static unsigned long lpc32xx_gpo_get_block(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ struct lpc32xx_gpio_chip *group = to_lpc32xx_gpio(chip);
+ u32 bits = __raw_readl(group->gpio_grp->outp_state);
+
+ return bits & mask;
+}
+
static int lpc32xx_gpio_request(struct gpio_chip *chip, unsigned pin)
{
if (pin < chip->ngpio)
@@ -440,8 +511,10 @@ static struct lpc32xx_gpio_chip lpc32xx_
.label = "gpio_p0",
.direction_input = lpc32xx_gpio_dir_input_p012,
.get = lpc32xx_gpio_get_value_p012,
+ .get_block = lpc32xx_gpi_get_block,
.direction_output = lpc32xx_gpio_dir_output_p012,
.set = lpc32xx_gpio_set_value_p012,
+ .set_block = lpc32xx_gpo_set_block,
.request = lpc32xx_gpio_request,
.to_irq = lpc32xx_gpio_to_irq_p01,
.base = LPC32XX_GPIO_P0_GRP,
@@ -456,8 +529,10 @@ static struct lpc32xx_gpio_chip lpc32xx_
.label = "gpio_p1",
.direction_input = lpc32xx_gpio_dir_input_p012,
.get = lpc32xx_gpio_get_value_p012,
+ .get_block = lpc32xx_gpi_get_block,
.direction_output = lpc32xx_gpio_dir_output_p012,
.set = lpc32xx_gpio_set_value_p012,
+ .set_block = lpc32xx_gpo_set_block,
.request = lpc32xx_gpio_request,
.to_irq = lpc32xx_gpio_to_irq_p01,
.base = LPC32XX_GPIO_P1_GRP,
@@ -472,8 +547,10 @@ static struct lpc32xx_gpio_chip lpc32xx_
.label = "gpio_p2",
.direction_input = lpc32xx_gpio_dir_input_p012,
.get = lpc32xx_gpio_get_value_p012,
+ .get_block = lpc32xx_gpi_get_block,
.direction_output = lpc32xx_gpio_dir_output_p012,
.set = lpc32xx_gpio_set_value_p012,
+ .set_block = lpc32xx_gpo_set_block,
.request = lpc32xx_gpio_request,
.base = LPC32XX_GPIO_P2_GRP,
.ngpio = LPC32XX_GPIO_P2_MAX,
@@ -487,8 +564,10 @@ static struct lpc32xx_gpio_chip lpc32xx_
.label = "gpio_p3",
.direction_input = lpc32xx_gpio_dir_input_p3,
.get = lpc32xx_gpio_get_value_p3,
+ .get_block = lpc32xx_gpio_get_block_p3,
.direction_output = lpc32xx_gpio_dir_output_p3,
.set = lpc32xx_gpio_set_value_p3,
+ .set_block = lpc32xx_gpio_set_block_p3,
.request = lpc32xx_gpio_request,
.to_irq = lpc32xx_gpio_to_irq_gpio_p3,
.base = LPC32XX_GPIO_P3_GRP,
@@ -503,6 +582,7 @@ static struct lpc32xx_gpio_chip lpc32xx_
.label = "gpi_p3",
.direction_input = lpc32xx_gpio_dir_in_always,
.get = lpc32xx_gpi_get_value,
+ .get_block = lpc32xx_gpi_get_block,
.request = lpc32xx_gpio_request,
.to_irq = lpc32xx_gpio_to_irq_gpi_p3,
.base = LPC32XX_GPI_P3_GRP,
@@ -517,7 +597,9 @@ static struct lpc32xx_gpio_chip lpc32xx_
.label = "gpo_p3",
.direction_output = lpc32xx_gpio_dir_out_always,
.set = lpc32xx_gpo_set_value,
+ .set_block = lpc32xx_gpo_set_block,
.get = lpc32xx_gpo_get_value,
+ .get_block = lpc32xx_gpo_get_block,
.request = lpc32xx_gpio_request,
.base = LPC32XX_GPO_P3_GRP,
.ngpio = LPC32XX_GPO_P3_MAX,
--- linux-2.6.orig/drivers/gpio/gpio-max730x.c
+++ linux-2.6/drivers/gpio/gpio-max730x.c
@@ -146,6 +146,44 @@ static int max7301_get(struct gpio_chip
return level;
}
+static unsigned long max7301_get_block(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ struct max7301 *ts = container_of(chip, struct max7301, chip);
+ int i, j;
+ unsigned long result = 0;
+
+ for (i = 0; i < 4; i++) {
+ if ((mask >> (i * 8)) & 0xFF) { /* i/o only if necessary */
+ u8 in_level = ts->read(ts->dev, 0x44 + i * 8);
+ u8 in_mask = 0;
+ u8 out_level = (ts->out_level >> (i * 8 + 4)) & 0xFF;
+ u8 out_mask = 0;
+
+ for (j = 0; j < 8; j++) {
+ int offset = 4 + i * 8 + j;
+ int config = (ts->port_config[offset >> 2] >>
+ ((offset & 3) << 1)) &
+ PIN_CONFIG_MASK;
+
+ switch (config) {
+ case PIN_CONFIG_OUT:
+ out_mask |= BIT(j);
+ break;
+ case PIN_CONFIG_IN_WO_PULLUP:
+ case PIN_CONFIG_IN_PULLUP:
+ in_mask |= BIT(j);
+ }
+ }
+
+ result |= ((unsigned long)(in_level & in_mask) |
+ (out_level & out_mask)) << (i * 8);
+ }
+ }
+
+ return result & mask;
+}
+
static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct max7301 *ts = container_of(chip, struct max7301, chip);
@@ -160,6 +198,27 @@ static void max7301_set(struct gpio_chip
mutex_unlock(&ts->lock);
}
+static void max7301_set_block(struct gpio_chip *chip, unsigned long mask,
+ unsigned long values)
+{
+ struct max7301 *ts = container_of(chip, struct max7301, chip);
+ unsigned long changes;
+ int i;
+
+ mutex_lock(&ts->lock);
+
+ changes = (ts->out_level ^ (values << 4)) & (mask << 4);
+ ts->out_level ^= changes;
+
+ for (i = 0; i < 4; i++) {
+ if ((changes >> (i * 8 + 4)) & 0xFF) /* i/o only on change */
+ ts->write(ts->dev, 0x44 + i * 8,
+ (ts->out_level >> (i * 8 + 4)) & 0xFF);
+ }
+
+ mutex_unlock(&ts->lock);
+}
+
int __devinit __max730x_probe(struct max7301 *ts)
{
struct device *dev = ts->dev;
@@ -184,8 +243,10 @@ int __devinit __max730x_probe(struct max
ts->chip.direction_input = max7301_direction_input;
ts->chip.get = max7301_get;
+ ts->chip.get_block = max7301_get_block;
ts->chip.direction_output = max7301_direction_output;
ts->chip.set = max7301_set;
+ ts->chip.set_block = max7301_set_block;
ts->chip.ngpio = PIN_NUMBER;
ts->chip.can_sleep = 1;
--- linux-2.6.orig/drivers/gpio/gpio-max732x.c
+++ linux-2.6/drivers/gpio/gpio-max732x.c
@@ -219,6 +219,63 @@ out:
mutex_unlock(&chip->lock);
}
+static unsigned long max732x_gpio_get_block(struct gpio_chip *gc,
+ unsigned long mask)
+{
+ struct max732x_chip *chip;
+ uint8_t lo = 0;
+ uint8_t hi = 0;
+ int ret;
+
+ chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+ if (mask & 0xFF) {
+ ret = max732x_readb(chip, is_group_a(chip, 0), &lo);
+ if (ret < 0)
+ return 0;
+ }
+ if (mask & 0xFF00) {
+ ret = max732x_readb(chip, is_group_a(chip, 8), &hi);
+ if (ret < 0)
+ return 0;
+ }
+
+ return (((unsigned long)hi << 8) | lo) & mask;
+}
+
+static void max732x_gpio_set_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ struct max732x_chip *chip;
+ uint8_t reg_out;
+ uint8_t lo_mask = mask & 0xFF;
+ uint8_t hi_mask = (mask >> 8) & 0xFF;
+ int ret;
+
+ chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+ mutex_lock(&chip->lock);
+
+ if (lo_mask) {
+ reg_out = (chip->reg_out[0] & ~lo_mask) | (values & lo_mask);
+ ret = max732x_writeb(chip, is_group_a(chip, 0), reg_out);
+ if (ret < 0)
+ goto out;
+ chip->reg_out[0] = reg_out;
+ }
+ if (hi_mask) {
+ reg_out = (chip->reg_out[1] & ~hi_mask) |
+ ((values >> 8) & hi_mask);
+ ret = max732x_writeb(chip, is_group_a(chip, 8), reg_out);
+ if (ret < 0)
+ goto out;
+ chip->reg_out[1] = reg_out;
+ }
+
+out:
+ mutex_unlock(&chip->lock);
+}
+
static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
{
struct max732x_chip *chip;
@@ -562,8 +619,10 @@ static int __devinit max732x_setup_gpio(
if (chip->dir_output) {
gc->direction_output = max732x_gpio_direction_output;
gc->set = max732x_gpio_set_value;
+ gc->set_block = max732x_gpio_set_block;
}
gc->get = max732x_gpio_get_value;
+ gc->get_block = max732x_gpio_get_block;
gc->can_sleep = 1;
gc->base = gpio_start;
--- linux-2.6.orig/drivers/gpio/gpio-pca953x.c
+++ linux-2.6/drivers/gpio/gpio-pca953x.c
@@ -300,6 +300,68 @@ exit:
mutex_unlock(&chip->i2c_lock);
}
+static unsigned long pca953x_gpio_get_block(struct gpio_chip *gc,
+ unsigned long mask)
+{
+ struct pca953x_chip *chip;
+ u32 reg_val;
+ int ret, offset = 0;
+
+ chip = container_of(gc, struct pca953x_chip, gpio_chip);
+
+ mutex_lock(&chip->i2c_lock);
+ switch (chip->chip_type) {
+ case PCA953X_TYPE:
+ offset = PCA953X_INPUT;
+ break;
+ case PCA957X_TYPE:
+ offset = PCA957X_IN;
+ break;
+ }
+ ret = pca953x_read_reg(chip, offset, ®_val);
+ mutex_unlock(&chip->i2c_lock);
+ if (ret < 0) {
+ /* NOTE: diagnostic already emitted; that's all we should
+ * do unless gpio_*_value_cansleep() calls become different
+ * from their nonsleeping siblings (and report faults).
+ */
+ return 0;
+ }
+
+ return reg_val & mask;
+}
+
+static void pca953x_gpio_set_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ struct pca953x_chip *chip;
+ u32 reg_val;
+ int ret, offset = 0;
+
+ chip = container_of(gc, struct pca953x_chip, gpio_chip);
+
+ mutex_lock(&chip->i2c_lock);
+
+ reg_val = chip->reg_output & ~mask;
+ reg_val |= values & mask;
+
+ switch (chip->chip_type) {
+ case PCA953X_TYPE:
+ offset = PCA953X_OUTPUT;
+ break;
+ case PCA957X_TYPE:
+ offset = PCA957X_OUT;
+ break;
+ }
+ ret = pca953x_write_reg(chip, offset, reg_val);
+ if (ret)
+ goto exit;
+
+ chip->reg_output = reg_val;
+exit:
+ mutex_unlock(&chip->i2c_lock);
+}
+
static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
{
struct gpio_chip *gc;
@@ -310,6 +372,8 @@ static void pca953x_setup_gpio(struct pc
gc->direction_output = pca953x_gpio_direction_output;
gc->get = pca953x_gpio_get_value;
gc->set = pca953x_gpio_set_value;
+ gc->get_block = pca953x_gpio_get_block;
+ gc->set_block = pca953x_gpio_set_block;
gc->can_sleep = 1;
gc->base = chip->gpio_start;
--- linux-2.6.orig/drivers/gpio/gpio-pcf857x.c
+++ linux-2.6/drivers/gpio/gpio-pcf857x.c
@@ -158,6 +158,28 @@ static void pcf857x_set(struct gpio_chip
pcf857x_output(chip, offset, value);
}
+static unsigned long pcf857x_get_block(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
+ int value;
+
+ value = gpio->read(gpio->client);
+ return (value < 0) ? 0 : (value & mask);
+}
+
+static void pcf857x_set_block(struct gpio_chip *chip, unsigned long mask,
+ unsigned long values)
+{
+ struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
+
+ mutex_lock(&gpio->lock);
+ gpio->out &= ~mask;
+ gpio->out |= values & mask;
+ gpio->write(gpio->client, gpio->out);
+ mutex_unlock(&gpio->lock);
+}
+
/*-------------------------------------------------------------------------*/
static int pcf857x_to_irq(struct gpio_chip *chip, unsigned offset)
@@ -280,6 +302,8 @@ static int pcf857x_probe(struct i2c_clie
gpio->chip.owner = THIS_MODULE;
gpio->chip.get = pcf857x_get;
gpio->chip.set = pcf857x_set;
+ gpio->chip.get_block = pcf857x_get_block;
+ gpio->chip.set_block = pcf857x_set_block;
gpio->chip.direction_input = pcf857x_input;
gpio->chip.direction_output = pcf857x_output;
gpio->chip.ngpio = id->driver_data;
--- linux-2.6.orig/drivers/gpio/gpio-pch.c
+++ linux-2.6/drivers/gpio/gpio-pch.c
@@ -122,6 +122,23 @@ static void pch_gpio_set(struct gpio_chi
spin_unlock_irqrestore(&chip->spinlock, flags);
}
+static void pch_gpio_set_block(struct gpio_chip *gpio, unsigned long mask,
+ unsigned long values)
+{
+ u32 reg_val;
+ struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
+ unsigned long flags;
+
+ spin_lock_irqsave(&chip->spinlock, flags);
+ reg_val = ioread32(&chip->reg->po);
+
+ reg_val &= ~mask;
+ reg_val |= values & mask;
+
+ iowrite32(reg_val, &chip->reg->po);
+ spin_unlock_irqrestore(&chip->spinlock, flags);
+}
+
static int pch_gpio_get(struct gpio_chip *gpio, unsigned nr)
{
struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
@@ -129,6 +146,14 @@ static int pch_gpio_get(struct gpio_chip
return ioread32(&chip->reg->pi) & (1 << nr);
}
+static unsigned long pch_gpio_get_block(struct gpio_chip *gpio,
+ unsigned long mask)
+{
+ struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
+
+ return ioread32(&chip->reg->pi) & mask;
+}
+
static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
int val)
{
@@ -218,8 +243,10 @@ static void pch_gpio_setup(struct pch_gp
gpio->owner = THIS_MODULE;
gpio->direction_input = pch_gpio_direction_input;
gpio->get = pch_gpio_get;
+ gpio->get_block = pch_gpio_get_block;
gpio->direction_output = pch_gpio_direction_output;
gpio->set = pch_gpio_set;
+ gpio->set_block = pch_gpio_set_block;
gpio->dbg_show = NULL;
gpio->base = -1;
gpio->ngpio = gpio_pins[chip->ioh];
--- linux-2.6.orig/drivers/gpio/gpio-pl061.c
+++ linux-2.6/drivers/gpio/gpio-pl061.c
@@ -123,6 +123,21 @@ static void pl061_set_value(struct gpio_
writeb(!!value << offset, chip->base + (1 << (offset + 2)));
}
+static unsigned long pl061_get_block(struct gpio_chip *gc, unsigned long mask)
+{
+ struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+
+ return !!readb(chip->base + (mask << 2));
+}
+
+static void pl061_set_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
+
+ writeb(values & mask, chip->base + (mask << 2));
+}
+
static int pl061_to_irq(struct gpio_chip *gc, unsigned offset)
{
struct pl061_gpio *chip = container_of(gc, struct pl061_gpio, gc);
@@ -256,6 +271,8 @@ static int pl061_probe(struct amba_devic
chip->gc.direction_output = pl061_direction_output;
chip->gc.get = pl061_get_value;
chip->gc.set = pl061_set_value;
+ chip->gc.get_block = pl061_get_block;
+ chip->gc.set_block = pl061_set_block;
chip->gc.to_irq = pl061_to_irq;
chip->gc.ngpio = PL061_GPIO_NR;
chip->gc.label = dev_name(&dev->dev);
--- linux-2.6.orig/drivers/gpio/gpio-twl6040.c
+++ linux-2.6/drivers/gpio/gpio-twl6040.c
@@ -46,6 +46,19 @@ static int twl6040gpo_get(struct gpio_ch
return (ret >> offset) & 1;
}
+static unsigned long twl6040gpo_get_block(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ struct twl6040 *twl6040 = dev_get_drvdata(chip->dev->parent);
+ int ret = 0;
+
+ ret = twl6040_reg_read(twl6040, TWL6040_REG_GPOCTL);
+ if (ret < 0)
+ return 0;
+
+ return ret & mask;
+}
+
static int twl6040gpo_direction_out(struct gpio_chip *chip, unsigned offset,
int value)
{
@@ -71,12 +84,31 @@ static void twl6040gpo_set(struct gpio_c
twl6040_reg_write(twl6040, TWL6040_REG_GPOCTL, gpoctl);
}
+static void twl6040gpo_set_block(struct gpio_chip *chip, unsigned long mask,
+ unsigned long values)
+{
+ struct twl6040 *twl6040 = dev_get_drvdata(chip->dev->parent);
+ int ret;
+ u8 gpoctl;
+
+ ret = twl6040_reg_read(twl6040, TWL6040_REG_GPOCTL);
+ if (ret < 0)
+ return;
+
+ gpoctl = ret & ~mask;
+ gpoctl |= values & mask;
+
+ twl6040_reg_write(twl6040, TWL6040_REG_GPOCTL, gpoctl);
+}
+
static struct gpio_chip twl6040gpo_chip = {
.label = "twl6040",
.owner = THIS_MODULE,
.get = twl6040gpo_get,
+ .get_block = twl6040gpo_get_block,
.direction_output = twl6040gpo_direction_out,
.set = twl6040gpo_set,
+ .set_block = twl6040gpo_set_block,
.can_sleep = 1,
};
--- linux-2.6.orig/drivers/gpio/gpio-ucb1400.c
+++ linux-2.6/drivers/gpio/gpio-ucb1400.c
@@ -45,6 +45,27 @@ static void ucb1400_gpio_set(struct gpio
ucb1400_gpio_set_value(gpio->ac97, off, val);
}
+static unsigned long ucb1400_gpio_get_block(struct gpio_chip *gc,
+ unsigned long mask)
+{
+ struct ucb1400_gpio *gpio;
+ gpio = container_of(gc, struct ucb1400_gpio, gc);
+ return ucb1400_reg_read(gpio->ac97, UCB_IO_DATA) & mask;
+}
+
+static void ucb1400_gpio_set_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ struct ucb1400_gpio *gpio;
+ u16 tmp;
+ gpio = container_of(gc, struct ucb1400_gpio, gc);
+
+ tmp = ucb1400_reg_read(gpio->ac97, UCB_IO_DATA) & ~mask;
+ tmp |= values & mask;
+
+ ucb1400_reg_write(gpio->ac97, UCB_IO_DATA, tmp);
+}
+
static int ucb1400_gpio_probe(struct platform_device *dev)
{
struct ucb1400_gpio *ucb = dev->dev.platform_data;
@@ -66,6 +87,8 @@ static int ucb1400_gpio_probe(struct pla
ucb->gc.direction_output = ucb1400_gpio_dir_out;
ucb->gc.get = ucb1400_gpio_get;
ucb->gc.set = ucb1400_gpio_set;
+ ucb->gc.get_block = ucb1400_gpio_get_block;
+ ucb->gc.set_block = ucb1400_gpio_set_block;
ucb->gc.can_sleep = 1;
err = gpiochip_add(&ucb->gc);
--- linux-2.6.orig/drivers/gpio/gpio-vt8500.c
+++ linux-2.6/drivers/gpio/gpio-vt8500.c
@@ -209,6 +209,28 @@ static void vt8500_gpio_set_value(struct
writel_relaxed(val, vt8500_chip->base + vt8500_chip->regs->data_out);
}
+static unsigned long vt8500_gpio_get_block(struct gpio_chip *chip,
+ unsigned long mask)
+{
+ struct vt8500_gpio_chip *vt8500_chip = to_vt8500(chip);
+
+ return readl_relaxed(vt8500_chip->base + vt8500_chip->regs->data_in) &
+ mask;
+}
+
+static void vt8500_gpio_set_block(struct gpio_chip *chip, unsigned long mask,
+ unsigned long values)
+{
+ struct vt8500_gpio_chip *vt8500_chip = to_vt8500(chip);
+
+ u32 val = readl_relaxed(vt8500_chip->base +
+ vt8500_chip->regs->data_out);
+ val &= ~mask;
+ val |= values & mask;
+
+ writel_relaxed(val, vt8500_chip->base + vt8500_chip->regs->data_out);
+}
+
static int vt8500_of_xlate(struct gpio_chip *gc,
const struct of_phandle_args *gpiospec, u32 *flags)
{
@@ -251,6 +273,8 @@ static int vt8500_add_chips(struct platf
chip->direction_output = vt8500_gpio_direction_output;
chip->get = vt8500_gpio_get_value;
chip->set = vt8500_gpio_set_value;
+ chip->get_block = vt8500_gpio_get_block;
+ chip->set_block = vt8500_gpio_set_block;
chip->can_sleep = 0;
chip->base = pin_cnt;
chip->ngpio = data->banks[i].ngpio;
--- linux-2.6.orig/drivers/gpio/gpio-xilinx.c
+++ linux-2.6/drivers/gpio/gpio-xilinx.c
@@ -49,6 +49,21 @@ static int xgpio_get(struct gpio_chip *g
}
/**
+ * xgpio_get_block - Read a block of specified signals of the GPIO device.
+ * @gc: Pointer to gpio_chip device structure.
+ * @mask: Bit mask (bit 0 == 0th GPIO) for GPIOs to get
+ *
+ * This function reads a block of specified signal of the GPIO device, returned
+ * as a bit mask, each bit representing a GPIO
+ */
+static unsigned long xgpio_get_block(struct gpio_chip *gc, unsigned long mask)
+{
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+
+ return in_be32(mm_gc->regs + XGPIO_DATA_OFFSET) & mask;
+}
+
+/**
* xgpio_set - Write the specified signal of the GPIO device.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
@@ -77,6 +92,33 @@ static void xgpio_set(struct gpio_chip *
}
/**
+ * xgpio_set_block - Write a block of specified signals of the GPIO device.
+ * @gc: Pointer to gpio_chip device structure.
+ * @mask: Bit mask (bit 0 == 0th GPIO) for GPIOs to set
+ * @values: Bit mapped values
+ *
+ * This function writes the specified values in to the specified signals of the
+ * GPIO device.
+ */
+static void xgpio_set_block(struct gpio_chip *gc, unsigned long mask,
+ unsigned long values)
+{
+ unsigned long flags;
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+ struct xgpio_instance *chip =
+ container_of(mm_gc, struct xgpio_instance, mmchip);
+
+ spin_lock_irqsave(&chip->gpio_lock, flags);
+
+ chip->gpio_state &= ~mask;
+ chip->gpio_state |= mask & values;
+
+ out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
+
+ spin_unlock_irqrestore(&chip->gpio_lock, flags);
+}
+
+/**
* xgpio_dir_in - Set the direction of the specified GPIO signal as input.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
@@ -195,6 +237,8 @@ static int __devinit xgpio_of_probe(stru
chip->mmchip.gc.direction_output = xgpio_dir_out;
chip->mmchip.gc.get = xgpio_get;
chip->mmchip.gc.set = xgpio_set;
+ chip->mmchip.gc.get_block = xgpio_get_block;
+ chip->mmchip.gc.set_block = xgpio_set_block;
chip->mmchip.save_regs = xgpio_save_regs;
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 0/6 v8] gpio: Add block GPIO
2012-11-30 18:03 [PATCH 0/6 v8] gpio: Add block GPIO Roland Stigge
` (5 preceding siblings ...)
2012-11-30 18:03 ` [PATCH 6/6 v8] gpio: Add block gpio to several gpio drivers Roland Stigge
@ 2012-12-03 9:17 ` Wolfgang Grandegger
2012-12-04 20:39 ` Roland Stigge
6 siblings, 1 reply; 11+ messages in thread
From: Wolfgang Grandegger @ 2012-12-03 9:17 UTC (permalink / raw)
To: Roland Stigge
Cc: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr
Hi Roland,
On 11/30/2012 07:03 PM, Roland Stigge wrote:
> This set of patches adds:
>
> * Block GPIO API to gpiolib
> * Sysfs support for GPIO API, to provide userland access
> * Device interface for userland access (alternative to sysfs)
> * Devicetree support to instantiate GPIO blocks via DT
> * Example implementations in several gpio drivers since they need
> special accessor functions for block wise GPIO access
> * Fix for race condition in gpiolib on device creation
>
> Signed-off-by: Roland Stigge <stigge@antcom.de>
> --
>
> Changes since v7:
> * Fixed error in API documentation (name arg missing in prototype)
> * Fixed compile error if sysfs is missing: Moved gpio_block_is_output()
> out of sysfs-ifdef
> * Added error handling to gpio_block_register()
> * Added mask attribute to sysfs (although dev interface exists now)
>
> Changes since v6:
> * Changed realloc to list handling
> * Added mask to kernel API
> * Added device interface as userspace API
> * Changed sizeof() to BITS_PER_LONG
> * Fixed multiline comment style
> * Documented direction setting by the user
> * Documented order of handled chips in case of multiple chips in one block
>
> Changes since v5:
> * Documented sysfs: elaborated on "exported" and "values" attributes
> * Documented sysfs: gpiochip is a separate class now
> * Aggregated driver support patches for block gpio into one single patch
> * Added gpio block driver support for twl6040 and pch
>
> Changes since v4:
> * Documented word width
> * Bugfix: export/unexport on register/unregister
> * Using default dev_attrs for gpio_block_class
> * Fix gpiolib: race condition on device creation
> * Added driver support for ucb14500, vt8500, xilinx
>
> Changes since v3:
> * Added driver support for pca953x, em, pl061, max732x, pcf857x
> * Coding style improvements
> * Fixed krealloc memory leak in error case
> * sysfs: values in hex
> * Register blocks in a list
> * Narrowing lock scope
> * Use S_IWUSR and S_IRUGO instead of direct octal values
> * Use for_each_set_bit()
> * Change from unsigned to unsigned long for masks and values
>
> Changes since v2:
> * Added sysfs support
> * Added devicetree support
> * Added support for lpc32xx, generic
> * Added functions for GPIO block registration
> * Added more error checking
> * Bit remapping bugfix
>
> Changes since v1:
> * API change to 32/64 bit word, bit masks
>
> Thanks to Ryan Mallon, Linus Walleij, Stijn Devriendt, Jean-Christophe
> Plagniol-Villard, Mark Brown, Greg Kroah-Hartman, Grant Likely, Stefan
> Roese and Wolfgang Grandegger for reviewing!
I re-tried v8 on my AT91-SAM9G45 board and it works fine if
CONFIG_GPIO_SYSFS is enable. Unfortunately, the access via misc device
fails if CONFIG_GPIO_SYSFS is not set. That's due to gpio_block_export()
returning -ENOSYS in gpio_block_register().
Anyway, I really like that new GPIO block interface making life for
applications fiddling with GPIOs much easier and faster. Just the poll
support is missing.
Thanks,
Wolfgang.
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 0/6 v8] gpio: Add block GPIO
2012-12-03 9:17 ` [PATCH 0/6 v8] gpio: Add block GPIO Wolfgang Grandegger
@ 2012-12-04 20:39 ` Roland Stigge
2012-12-05 18:44 ` Wolfgang Grandegger
0 siblings, 1 reply; 11+ messages in thread
From: Roland Stigge @ 2012-12-04 20:39 UTC (permalink / raw)
To: Wolfgang Grandegger
Cc: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr
Hi Wolfgang,
On 03/12/12 10:17, Wolfgang Grandegger wrote:
> I re-tried v8 on my AT91-SAM9G45 board and it works fine if
> CONFIG_GPIO_SYSFS is enable. Unfortunately, the access via misc device
> fails if CONFIG_GPIO_SYSFS is not set. That's due to gpio_block_export()
> returning -ENOSYS in gpio_block_register().
>
> Anyway, I really like that new GPIO block interface making life for
> applications fiddling with GPIOs much easier and faster. Just the poll
> support is missing.
Thanks for your feedback!
I'm posting an update (v9) which includes poll() support in the dev
interface.
Some issues regarding IRQ driven poll() remain:
* What would be the correct locking mechanism for the got_int flag (set
in the isr and reset on read()'s return), if necessary at all?
* There is probably an explicit interrupt configuration necessary (via
struct gpio_block, and devicetree, respectively) since there are
constellations where gpio_to_irq() isn't working. E.g., in contrast to
controllers which are aware of their IRQs and providing to_irq(), there
is typically independent wiring from GPIO expander chips' interrupt line
to individual IRQ inputs on SoCs/CPUs. Or should all this be solved via
devicetree and drivers (which should support IRQ config where possible)?
* For the same reason, the IRQ flags are currently IRQF_TRIGGER_FALLING,
which isn't flexible. Instead, either preset by board setup/firmware, or
via interrupts config in devicetree (optional property of a GPIO block?)
* Some GPIOs' IRQs are not suitable for GPI input change detection. E.g.
on LPC32xx, I can configure the IRQ which is controlled directly by the
GPI's values as FALLING, RISING, HIGH /exclusive/ or LOW. I.e., this way
it's not possible to detect both 0->1 and 1->0 changes without
reconfiguring the GPIO controller inbetween. Other controllers provide a
dedicated interrupt on all values changes.
* Would IRQF_SHARED be appropriate to enable opening IRQ enabled GPIO
blocks multiple times?
Thanks,
Roland
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 0/6 v8] gpio: Add block GPIO
2012-12-04 20:39 ` Roland Stigge
@ 2012-12-05 18:44 ` Wolfgang Grandegger
2012-12-05 22:10 ` Roland Stigge
0 siblings, 1 reply; 11+ messages in thread
From: Wolfgang Grandegger @ 2012-12-05 18:44 UTC (permalink / raw)
To: Roland Stigge
Cc: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr
Hi Roland,
On 12/04/2012 09:39 PM, Roland Stigge wrote:
> Hi Wolfgang,
>
> On 03/12/12 10:17, Wolfgang Grandegger wrote:
>> I re-tried v8 on my AT91-SAM9G45 board and it works fine if
>> CONFIG_GPIO_SYSFS is enable. Unfortunately, the access via misc device
>> fails if CONFIG_GPIO_SYSFS is not set. That's due to gpio_block_export()
>> returning -ENOSYS in gpio_block_register().
>>
>> Anyway, I really like that new GPIO block interface making life for
>> applications fiddling with GPIOs much easier and faster. Just the poll
>> support is missing.
>
> Thanks for your feedback!
>
> I'm posting an update (v9) which includes poll() support in the dev
> interface.
I just gave it a try and it was working after replacing
IRQF_TRIGGER_FALLING with 0 in the request_irq in the device open:
# ./gpio_block_test
mask=0x7e
mask=0x7f
mask=0x7d
mask=0x7f
mask=0x77
mask=0x7f
Otherwise it get:
# ./gpio_block_test
genirq: Setting trigger mode 2 for irq 86 failed (gpio_irq_type+0x0/0x18)
can't open device /dev/gpiobuttons (Invalid argument)
Also opening with O_NONBLOCK works as expected.
> Some issues regarding IRQ driven poll() remain:
>
> * What would be the correct locking mechanism for the got_int flag (set
> in the isr and reset on read()'s return), if necessary at all?
If you sync against the interrupt context, I think spin_lock_irqsave and
spin_unlock_irqrestore should be used.
> * There is probably an explicit interrupt configuration necessary (via
> struct gpio_block, and devicetree, respectively) since there are
> constellations where gpio_to_irq() isn't working. E.g., in contrast to
> controllers which are aware of their IRQs and providing to_irq(), there
> is typically independent wiring from GPIO expander chips' interrupt line
> to individual IRQ inputs on SoCs/CPUs. Or should all this be solved via
> devicetree and drivers (which should support IRQ config where possible)?
Yes, I think it's up to the device tree or platform code to properly setup
the interrupt... like for defining the GPIO block.
> * For the same reason, the IRQ flags are currently IRQF_TRIGGER_FALLING,
> which isn't flexible. Instead, either preset by board setup/firmware, or
> via interrupts config in devicetree (optional property of a GPIO block?)
Yes, and it did fail on my setup.
> * Some GPIOs' IRQs are not suitable for GPI input change detection. E.g.
> on LPC32xx, I can configure the IRQ which is controlled directly by the
> GPI's values as FALLING, RISING, HIGH /exclusive/ or LOW. I.e., this way
> it's not possible to detect both 0->1 and 1->0 changes without
> reconfiguring the GPIO controller inbetween. Other controllers provide a
> dedicated interrupt on all values changes.
Hm.
> * Would IRQF_SHARED be appropriate to enable opening IRQ enabled GPIO
> blocks multiple times?
Sounds reasonable for me. Some more comments in the patch mails...
Wolfgang.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 0/6 v8] gpio: Add block GPIO
2012-12-05 18:44 ` Wolfgang Grandegger
@ 2012-12-05 22:10 ` Roland Stigge
0 siblings, 0 replies; 11+ messages in thread
From: Roland Stigge @ 2012-12-05 22:10 UTC (permalink / raw)
To: Wolfgang Grandegger
Cc: gregkh, grant.likely, linus.walleij, linux-kernel,
linux-arm-kernel, w.sang, jbe, plagnioj, highguy, broonie,
daniel-gl, rmallon, tru, sr
Hi Wolfgang,
On 05/12/12 19:44, Wolfgang Grandegger wrote:
>> * There is probably an explicit interrupt configuration necessary (via
>> struct gpio_block, and devicetree, respectively) since there are
>> constellations where gpio_to_irq() isn't working. E.g., in contrast to
>> controllers which are aware of their IRQs and providing to_irq(), there
>> is typically independent wiring from GPIO expander chips' interrupt line
>> to individual IRQ inputs on SoCs/CPUs. Or should all this be solved via
>> devicetree and drivers (which should support IRQ config where possible)?
>
> Yes, I think it's up to the device tree or platform code to properly setup
> the interrupt... like for defining the GPIO block.
OK, sounds reasonable. Luckily, in reality it already works fine in this
regard with many current drivers.
>> * For the same reason, the IRQ flags are currently IRQF_TRIGGER_FALLING,
>> which isn't flexible. Instead, either preset by board setup/firmware, or
>> via interrupts config in devicetree (optional property of a GPIO block?)
>
> Yes, and it did fail on my setup.
OK, will replace the flags with 0 (and need to fix my own board setup ;-) ).
>> * Some GPIOs' IRQs are not suitable for GPI input change detection. E.g.
>> on LPC32xx, I can configure the IRQ which is controlled directly by the
>> GPI's values as FALLING, RISING, HIGH /exclusive/ or LOW. I.e., this way
>> it's not possible to detect both 0->1 and 1->0 changes without
>> reconfiguring the GPIO controller inbetween. Other controllers provide a
>> dedicated interrupt on all values changes.
>
> Hm.
For now, we are expecting IRQs to fire on "changes". Otherwise, the user
needs to handle the issue manually, using busy polling, manual
reconfiguration of the GPIO controller etc.
>> * Would IRQF_SHARED be appropriate to enable opening IRQ enabled GPIO
>> blocks multiple times?
>
> Sounds reasonable for me. Some more comments in the patch mails...
OK, will do in the next update.
Thanks for your feedback,
Roland
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