[RFC PATCH 1/5] Rework OpenFirmware GPIO handling
Dmitry Eremin-Solenikov
dbaryshkov at gmail.com
Wed Nov 18 02:42:22 EST 2009
This patch improves OF GPIO bindings so, that most non-OF-specific gpio
controllers don't need to call any of OF binding function:
0) Move of_gpio_chip into main gpio_chip structure.
1) Call of_gpio_init/destroy from gpiochip_add/remove.
2) By default supply reasonable defaults for gpio_cells/xlate
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov at gmail.com>
---
drivers/gpio/gpiolib.c | 6 ++++++
drivers/of/gpio.c | 42 ++++++++++++++++++++++++++++++++++++------
include/asm-generic/gpio.h | 19 +++++++++++++++++++
include/linux/of_gpio.h | 29 ++++++++++++++++-------------
4 files changed, 77 insertions(+), 19 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 50de0f5..7c998b3 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -10,6 +10,8 @@
#include <linux/gpio.h>
#include <linux/idr.h>
+#include <linux/of_gpio.h>
+
/* Optional implementation infrastructure for GPIO interfaces.
*
@@ -963,6 +965,8 @@ unlock:
spin_unlock_irqrestore(&gpio_lock, flags);
if (status == 0)
status = gpiochip_export(chip);
+ if (status == 0)
+ of_gpio_init(chip);
fail:
/* failures here can mean systems won't boot... */
if (status)
@@ -994,6 +998,8 @@ int gpiochip_remove(struct gpio_chip *chip)
}
}
if (status == 0) {
+ of_gpio_destroy(chip);
+
for (id = chip->base; id < chip->base + chip->ngpio; id++)
gpio_desc[id].chip = NULL;
}
diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
index 6eea601..903e79f 100644
--- a/drivers/of/gpio.c
+++ b/drivers/of/gpio.c
@@ -70,7 +70,7 @@ int of_get_gpio_flags(struct device_node *np, int index,
if (ret < 0)
goto err1;
- ret += of_gc->gc.base;
+ ret += to_gpio_chip_of(of_gc)->base;
err1:
of_node_put(gc);
err0:
@@ -140,7 +140,7 @@ int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np,
return -EINVAL;
}
- if (*gpio > of_gc->gc.ngpio)
+ if (*gpio > to_gpio_chip_of(of_gc)->ngpio)
return -EINVAL;
if (flags)
@@ -176,7 +176,7 @@ int of_mm_gpiochip_add(struct device_node *np,
{
int ret = -ENOMEM;
struct of_gpio_chip *of_gc = &mm_gc->of_gc;
- struct gpio_chip *gc = &of_gc->gc;
+ struct gpio_chip *gc = &mm_gc->gc;
gc->label = kstrdup(np->full_name, GFP_KERNEL);
if (!gc->label)
@@ -188,9 +188,6 @@ int of_mm_gpiochip_add(struct device_node *np,
gc->base = -1;
- if (!of_gc->xlate)
- of_gc->xlate = of_gpio_simple_xlate;
-
if (mm_gc->save_regs)
mm_gc->save_regs(mm_gc);
@@ -217,3 +214,36 @@ err0:
return ret;
}
EXPORT_SYMBOL(of_mm_gpiochip_add);
+
+void of_gpio_init(struct gpio_chip *gc)
+{
+ struct of_gpio_chip *of_gc = &gc->of_gc;
+ struct device_node *np = gc->dev ?
+ dev_archdata_get_node(&gc->dev->archdata) :
+ NULL;
+
+ if (!of_gc->xlate) {
+ if (!of_gc->gpio_cells)
+ of_gc->gpio_cells = 2;
+ of_gc->xlate = of_gpio_simple_xlate;
+ }
+
+ if (np) {
+ of_node_get(np);
+ np->data = of_gc;
+ }
+}
+EXPORT_SYMBOL(of_gpio_init);
+
+void of_gpio_destroy(struct gpio_chip *gc)
+{
+ struct device_node *np = gc->dev ?
+ dev_archdata_get_node(&gc->dev->archdata) :
+ NULL;
+
+ if (np) {
+ np->data = NULL;
+ of_node_put(np);
+ }
+}
+EXPORT_SYMBOL(of_gpio_destroy);
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 66d6106..3a70958 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -31,6 +31,21 @@ static inline int gpio_is_valid(int number)
struct seq_file;
struct module;
+#ifdef CONFIG_OF_GPIO
+struct device_node;
+enum of_gpio_flags;
+
+/*
+ * Generic OF GPIO chip
+ */
+struct of_gpio_chip {
+ int gpio_cells;
+ int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
+ const void *gpio_spec, enum of_gpio_flags *flags);
+};
+#endif
+
+
/**
* struct gpio_chip - abstract a GPIO controller
* @label: for diagnostics
@@ -76,6 +91,10 @@ struct gpio_chip {
struct device *dev;
struct module *owner;
+#ifdef CONFIG_OF_GPIO
+ struct of_gpio_chip of_gc;
+#endif
+
int (*request)(struct gpio_chip *chip,
unsigned offset);
void (*free)(struct gpio_chip *chip,
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index fc2472c..99cf84f 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -32,25 +32,16 @@ enum of_gpio_flags {
#ifdef CONFIG_OF_GPIO
-/*
- * Generic OF GPIO chip
- */
-struct of_gpio_chip {
- struct gpio_chip gc;
- int gpio_cells;
- int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
- const void *gpio_spec, enum of_gpio_flags *flags);
-};
-
-static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
+static inline struct gpio_chip *to_gpio_chip_of(struct of_gpio_chip *of_gc)
{
- return container_of(gc, struct of_gpio_chip, gc);
+ return container_of(of_gc, struct gpio_chip, of_gc);
}
/*
* OF GPIO chip for memory mapped banks
*/
struct of_mm_gpio_chip {
+ struct gpio_chip gc;
struct of_gpio_chip of_gc;
void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
void __iomem *regs;
@@ -58,8 +49,11 @@ struct of_mm_gpio_chip {
static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
{
- struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
+ return container_of(gc, struct of_mm_gpio_chip, gc);
+}
+static inline struct of_mm_gpio_chip *to_of_mm_of_chip(struct of_gpio_chip *of_gc)
+{
return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
}
@@ -73,6 +67,9 @@ extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
struct device_node *np,
const void *gpio_spec,
enum of_gpio_flags *flags);
+
+extern void of_gpio_init(struct gpio_chip *gc);
+extern void of_gpio_destroy(struct gpio_chip *gc);
#else
/* Drivers may not strictly depend on the GPIO support, so let them link. */
@@ -87,6 +84,12 @@ static inline unsigned int of_gpio_count(struct device_node *np)
return 0;
}
+static inline void of_gpio_init(struct gpio_chip *gc)
+{
+}
+static inline void of_gpio_destroy(struct gpio_chip *gc)
+{
+}
#endif /* CONFIG_OF_GPIO */
/**
--
1.6.5
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