[PATCH v2] Documentation/pinctrl: various minor fixes
Linus Walleij
linus.walleij at linaro.org
Fri Dec 9 06:02:54 EST 2011
2011/12/8 Uwe Kleine-König <u.kleine-koenig at pengutronix.de>:
> - add some consts
> - don't use the group index alone to determine the value to write to
> foo's mux register. For spi and i2c the group index is always 0.
> Additionally using the function index makes much more sense as it
> generates a different value for each function/group pair.
> - fix a few syntax errors
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
Some of these were fixed in earlier documentation patches in
my tree, so I took out the pieces that were missing and squashed
into that patch. The result now looks like this:
commit 478781254aea577029c7872bab5578e98ef0cbad
Author: Linus Walleij <linus.walleij at linaro.org>
Date: Thu Nov 10 09:27:41 2011 +0100
pinctrl: documentation update
Update the docs removing an obsolete __refdata tag and document
the mysterious return value of pin_free(). And fixes up some various
confusions in the pinctrl documentation.
Reported-by: Rajendra Nayak <rnayak at ti.com>
Reported-by: Randy Dunlap <rdunlap at xenotime.net>
Reported-by: Thomas Abraham <thomas.abraham at linaro.org>
Reported-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
Acked-by: Stephen Warren <swarren at nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
index b04cb7d..0a8b225 100644
--- a/Documentation/pinctrl.txt
+++ b/Documentation/pinctrl.txt
@@ -32,7 +32,7 @@ Definition of PIN:
be sparse - i.e. there may be gaps in the space with numbers where no
pin exists.
-When a PIN CONTROLLER is instatiated, it will register a descriptor to the
+When a PIN CONTROLLER is instantiated, it will register a descriptor to the
pin control framework, and this descriptor contains an array of pin descriptors
describing the pins handled by this specific pin controller.
@@ -61,14 +61,14 @@ this in our driver:
#include <linux/pinctrl/pinctrl.h>
-const struct pinctrl_pin_desc __refdata foo_pins[] = {
- PINCTRL_PIN(0, "A1"),
- PINCTRL_PIN(1, "A2"),
- PINCTRL_PIN(2, "A3"),
+const struct pinctrl_pin_desc foo_pins[] = {
+ PINCTRL_PIN(0, "A8"),
+ PINCTRL_PIN(1, "B8"),
+ PINCTRL_PIN(2, "C8"),
...
- PINCTRL_PIN(61, "H6"),
- PINCTRL_PIN(62, "H7"),
- PINCTRL_PIN(63, "H8"),
+ PINCTRL_PIN(61, "F1"),
+ PINCTRL_PIN(62, "G1"),
+ PINCTRL_PIN(63, "H1"),
};
static struct pinctrl_desc foo_desc = {
@@ -91,8 +91,8 @@ int __init foo_probe(void)
Pins usually have fancier names than this. You can find these in the dataheet
for your chip. Notice that the core pinctrl.h file provides a fancy macro
called PINCTRL_PIN() to create the struct entries. As you can see I enumerated
-the pins from 0 in the upper left corner to 63 in the lower right corner,
-this enumeration was arbitrarily chosen, in practice you need to think
+the pins from 0 in the upper left corner to 63 in the lower right corner.
+This enumeration was arbitrarily chosen, in practice you need to think
through your numbering system so that it matches the layout of registers
and such things in your driver, or the code may become complicated. You must
also consider matching of offsets to the GPIO ranges that may be handled by
@@ -133,8 +133,8 @@ struct foo_group {
const unsigned num_pins;
};
-static unsigned int spi0_pins[] = { 0, 8, 16, 24 };
-static unsigned int i2c0_pins[] = { 24, 25 };
+static const unsigned int spi0_pins[] = { 0, 8, 16, 24 };
+static const unsigned int i2c0_pins[] = { 24, 25 };
static const struct foo_group foo_groups[] = {
{
@@ -242,7 +242,7 @@ chip a: [32 .. 47]
chip b: [48 .. 55]
When GPIO-specific functions in the pin control subsystem are called, these
-ranges will be used to look up the apropriate pin controller by inspecting
+ranges will be used to look up the appropriate pin controller by inspecting
and matching the pin to the pin ranges across all controllers. When a
pin controller handling the matching range is found, GPIO-specific functions
will be called on that specific pin controller.
@@ -438,7 +438,7 @@ you. Define enumerators only for the pins you can
control if that makes sense.
Assumptions:
-We assume that the number possible function maps to pin groups is limited by
+We assume that the number of possible function maps to pin groups is limited by
the hardware. I.e. we assume that there is no system where any function can be
mapped to any pin, like in a phone exchange. So the available pins groups for
a certain function will be limited to a few choices (say up to eight or so),
@@ -585,7 +585,7 @@ int foo_list_funcs(struct pinctrl_dev *pctldev,
unsigned selector)
const char *foo_get_fname(struct pinctrl_dev *pctldev, unsigned selector)
{
- return myfuncs[selector].name;
+ return foo_functions[selector].name;
}
static int foo_get_groups(struct pinctrl_dev *pctldev, unsigned selector,
@@ -600,16 +600,16 @@ static int foo_get_groups(struct pinctrl_dev
*pctldev, unsigned selector,
int foo_enable(struct pinctrl_dev *pctldev, unsigned selector,
unsigned group)
{
- u8 regbit = (1 << group);
+ u8 regbit = (1 << selector + group);
writeb((readb(MUX)|regbit), MUX)
return 0;
}
-int foo_disable(struct pinctrl_dev *pctldev, unsigned selector,
+void foo_disable(struct pinctrl_dev *pctldev, unsigned selector,
unsigned group)
{
- u8 regbit = (1 << group);
+ u8 regbit = (1 << selector + group);
writeb((readb(MUX) & ~(regbit)), MUX)
return 0;
@@ -683,7 +683,7 @@ spi on the second function mapping:
#include <linux/pinctrl/machine.h>
-static struct pinmux_map pmx_mapping[] = {
+static const struct pinmux_map pmx_mapping[] = {
{
.ctrl_dev_name = "pinctrl.0",
.function = "spi0",
@@ -714,7 +714,7 @@ for example if they are not yet instantiated or
cumbersome to obtain.
You register this pinmux mapping to the pinmux subsystem by simply:
- ret = pinmux_register_mappings(&pmx_mapping, ARRAY_SIZE(pmx_mapping));
+ ret = pinmux_register_mappings(pmx_mapping, ARRAY_SIZE(pmx_mapping));
Since the above construct is pretty common there is a helper macro to make
it even more compact which assumes you want to use pinctrl.0 and position
@@ -762,42 +762,42 @@ case), we define a mapping like this:
.name "2bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
- .group = "mmc0_0_grp",
+ .group = "mmc0_1_grp",
.dev_name = "foo-mmc.0",
},
{
.name "4bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
- .group = "mmc0_0_grp",
+ .group = "mmc0_1_grp",
.dev_name = "foo-mmc.0",
},
{
.name "4bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
- .group = "mmc0_1_grp",
+ .group = "mmc0_2_grp",
.dev_name = "foo-mmc.0",
},
{
.name "8bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
- .group = "mmc0_0_grp",
+ .group = "mmc0_1_grp",
.dev_name = "foo-mmc.0",
},
{
.name "8bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
- .group = "mmc0_1_grp",
+ .group = "mmc0_2_grp",
.dev_name = "foo-mmc.0",
},
{
.name "8bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
- .group = "mmc0_2_grp",
+ .group = "mmc0_3_grp",
.dev_name = "foo-mmc.0",
},
...
diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index c77aee5..0923824 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -174,6 +174,10 @@ out:
* @pin: the pin to free
* @gpio_range: the range matching the GPIO pin if this is a request for a
* single GPIO pin
+ *
+ * This function returns a pointer to the function name in use. This is used
+ * for callers that dynamically allocate a function name so it can be freed
+ * once the pin is free. This is done for GPIO request functions.
*/
static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
struct pinctrl_gpio_range *gpio_range)
Hope this looks OK for you Uwe.
Thanks,
Linus Walleij
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