[U-Boot] [RESEND PATCH V3 1/6] dm: gpio: add a default gpio xlate routine

Eric Nelson
2016-04-20T15:37:34Z

Many drivers use a common form of offset + flags for device
tree nodes. e.g.:
<&gpio1 2 GPIO_ACTIVE_LOW>

This patch adds a common implementation of this type of parsing
and calls it when a gpio driver doesn't supply its' own xlate
routine.

This will allow removal of the driver-specific versions in a
handful of drivers and simplify the addition of new drivers.

Signed-off-by: Eric Nelson <eric@nelint.com>
---
V2 removes parsing of offset from the gpio_find_and_xlate routine,
and only parses the offset and GPIO_ACTIVE_LOW flag when a
driver-specific xlate is unavailable.

V3 re-works tests of the argument count as suggested by Stephen Warren
and will allow parsing of nodes with no flags field:
<&gpio1 2>

drivers/gpio/gpio-uclass.c | 30 +++++++++++++++++++++++-------
include/asm-generic/gpio.h | 19 ++++++++++++++-----
2 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c
index b58d4e6..3e83cec 100644
--- a/drivers/gpio/gpio-uclass.c
+++ b/drivers/gpio/gpio-uclass.c
@@ -6,6 +6,7 @@

#include <common.h>
#include <dm.h>
+#include <dt-bindings/gpio/gpio.h>
#include <errno.h>
#include <fdtdec.h>
#include <malloc.h>
@@ -113,19 +114,33 @@ int gpio_lookup_name(const char *name, struct udevice **devp,
return 0;
}

+int gpio_xlate_offs_flags(struct udevice *dev,
+ struct gpio_desc *desc,
+ struct fdtdec_phandle_args *args)
+{
+ if (args->args_count < 1)
+ return -EINVAL;
+
+ desc->offset = args->args[0];
+
+ if (args->args_count < 2)
+ return 0;
+
+ if (args->args[1] & GPIO_ACTIVE_LOW)
+ desc->flags = GPIOD_ACTIVE_LOW;
+
+ return 0;
+}
+
static int gpio_find_and_xlate(struct gpio_desc *desc,
struct fdtdec_phandle_args *args)
{
struct dm_gpio_ops *ops = gpio_get_ops(desc->dev);

- /* Use the first argument as the offset by default */
- if (args->args_count > 0)
- desc->offset = args->args[0];
+ if (ops->xlate)
+ return ops->xlate(desc->dev, desc, args);
else
- desc->offset = -1;
- desc->flags = 0;
-
- return ops->xlate ? ops->xlate(desc->dev, desc, args) : 0;
+ return gpio_xlate_offs_flags(desc->dev, desc, args);
}

int dm_gpio_request(struct gpio_desc *desc, const char *label)
@@ -605,6 +620,7 @@ static int _gpio_request_by_name_nodev(const void *blob, int node,

desc->dev = NULL;
desc->offset = 0;
+ desc->flags = 0;
ret = fdtdec_parse_phandle_with_args(blob, node, list_name,
"#gpio-cells", 0, index, &args);
if (ret) {
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 68b5f0b..2500c10 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -207,6 +207,16 @@ int gpio_requestf(unsigned gpio, const char *fmt, ...)
struct fdtdec_phandle_args;

/**
+ * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate
+ *
+ * This routine sets the offset field to args[0] and the flags field to
+ * GPIOD_ACTIVE_LOW if the GPIO_ACTIVE_LOW flag is present in args[1].
+ *
+ */
+int gpio_xlate_offs_flags(struct udevice *dev, struct gpio_desc *desc,
+ struct fdtdec_phandle_args *args);
+
+/**
* struct struct dm_gpio_ops - Driver model GPIO operations
*
* Refer to functions above for description. These function largely copy
@@ -258,12 +268,11 @@ struct dm_gpio_ops {
*
* @desc->dev to @dev
* @desc->flags to 0
- * @desc->offset to the value of the first argument in args, if any,
- * otherwise -1 (which is invalid)
+ * @desc->offset to 0
*
- * This method is optional so if the above defaults suit it can be
- * omitted. Typical behaviour is to set up the GPIOD_ACTIVE_LOW flag
- * in desc->flags.
+ * This method is optional and defaults to gpio_xlate_offs_flags,
+ * which will parse offset and the GPIO_ACTIVE_LOW flag in the first
+ * two arguments.
*
* Note that @dev is passed in as a parameter to follow driver model
* uclass conventions, even though it is already available as
--
2.6.2