aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/pinctrl.txt
diff options
context:
space:
mode:
authorStephen Warren <swarren@nvidia.com>2012-03-02 20:05:48 (GMT)
committerLinus Walleij <linus.walleij@linaro.org>2012-03-05 10:25:11 (GMT)
commit1e2082b520721734c358f776d34a069867214c8e (patch)
tree4d11e15a4127ad69faf7555864480a6fafe5422c /Documentation/pinctrl.txt
parent6e5e959dde0d92d177f035652aeaa77f9330c9c6 (diff)
pinctrl: enhance mapping table to support pin config operations
The pinctrl mapping table can now contain entries to: * Set the mux function of a pin group * Apply a set of pin config options to a pin or a group This allows pinctrl_select_state() to apply pin configs settings as well as mux settings. v3: Fix find_pinctrl() to iterate over the correct list. s/_MUX_CONFIGS_/_CONFIGS_/ in mapping table macros. Fix documentation to use correct mapping table macro. v2: Added numerous extra PIN_MAP_*() special-case macros. Fixed kerneldoc typo. Delete pinctrl_get_pin_id() and replace it with pin_get_from_name(). Various minor fixes. Updates due to rebase. Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Dong Aisheng <dong.aisheng@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'Documentation/pinctrl.txt')
-rw-r--r--Documentation/pinctrl.txt76
1 files changed, 64 insertions, 12 deletions
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
index 23426c7..d97bccf 100644
--- a/Documentation/pinctrl.txt
+++ b/Documentation/pinctrl.txt
@@ -206,14 +206,21 @@ using a certain resistor value - pull up and pull down - so that the pin has a
stable value when nothing is driving the rail it is connected to, or when it's
unconnected.
-For example, a platform may do this:
+Pin configuration can be programmed either using the explicit APIs described
+immediately below, or by adding configuration entries into the mapping table;
+see section "Board/machine configuration" below.
+
+For example, a platform may do the following to pull up a pin to VDD:
#include <linux/pinctrl/consumer.h>
ret = pin_config_set("foo-dev", "FOO_GPIO_PIN", PLATFORM_X_PULL_UP);
-To pull up a pin to VDD. The pin configuration driver implements callbacks for
-changing pin configuration in the pin controller ops like this:
+The format and meaning of the configuration parameter, PLATFORM_X_PULL_UP
+above, is entirely defined by the pin controller driver.
+
+The pin configuration driver implements callbacks for changing pin
+configuration in the pin controller ops like this:
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf.h>
@@ -765,7 +772,7 @@ obtain the function "gpioN" where "N" is the global GPIO pin number if no
special GPIO-handler is registered.
-Pinmux board/machine configuration
+Board/machine configuration
==================================
Boards and machines define how a certain complete running system is put
@@ -773,9 +780,9 @@ together, including how GPIOs and devices are muxed, how regulators are
constrained and how the clock tree looks. Of course pinmux settings are also
part of this.
-A pinmux config for a machine looks pretty much like a simple regulator
-configuration, so for the example array above we want to enable i2c and
-spi on the second function mapping:
+A pin controller configuration for a machine looks pretty much like a simple
+regulator configuration, so for the example array above we want to enable i2c
+and spi on the second function mapping:
#include <linux/pinctrl/machine.h>
@@ -783,20 +790,23 @@ static const struct pinctrl_map __initdata mapping[] = {
{
.dev_name = "foo-spi.0",
.name = PINCTRL_STATE_DEFAULT,
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
- .function = "spi0",
+ .data.mux.function = "spi0",
},
{
.dev_name = "foo-i2c.0",
.name = PINCTRL_STATE_DEFAULT,
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
- .function = "i2c0",
+ .data.mux.function = "i2c0",
},
{
.dev_name = "foo-mmc.0",
.name = PINCTRL_STATE_DEFAULT,
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
- .function = "mmc0",
+ .data.mux.function = "mmc0",
},
};
@@ -817,7 +827,40 @@ it even more compact which assumes you want to use pinctrl-foo and position
0 for mapping, for example:
static struct pinctrl_map __initdata mapping[] = {
- PIN_MAP(PINCTRL_STATE_DEFAULT, "pinctrl-foo", "i2c0", "foo-i2c.0"),
+ PIN_MAP_MUX_GROUP("foo-i2c.o", PINCTRL_STATE_DEFAULT, "pinctrl-foo", NULL, "i2c0"),
+};
+
+The mapping table may also contain pin configuration entries. It's common for
+each pin/group to have a number of configuration entries that affect it, so
+the table entries for configuration reference an array of config parameters
+and values. An example using the convenience macros is shown below:
+
+static unsigned long i2c_grp_configs[] = {
+ FOO_PIN_DRIVEN,
+ FOO_PIN_PULLUP,
+};
+
+static unsigned long i2c_pin_configs[] = {
+ FOO_OPEN_COLLECTOR,
+ FOO_SLEW_RATE_SLOW,
+};
+
+static struct pinctrl_map __initdata mapping[] = {
+ PIN_MAP_MUX_GROUP("foo-i2c.0", PINCTRL_STATE_DEFAULT, "pinctrl-foo", "i2c0", "i2c0"),
+ PIN_MAP_MUX_CONFIGS_GROUP("foo-i2c.0", PINCTRL_STATE_DEFAULT, "pinctrl-foo", "i2c0", i2c_grp_configs),
+ PIN_MAP_MUX_CONFIGS_PIN("foo-i2c.0", PINCTRL_STATE_DEFAULT, "pinctrl-foo", "i2c0scl", i2c_pin_configs),
+ PIN_MAP_MUX_CONFIGS_PIN("foo-i2c.0", PINCTRL_STATE_DEFAULT, "pinctrl-foo", "i2c0sda", i2c_pin_configs),
+};
+
+Finally, some devices expect the mapping table to contain certain specific
+named states. When running on hardware that doesn't need any pin controller
+configuration, the mapping table must still contain those named states, in
+order to explicitly indicate that the states were provided and intended to
+be empty. Table entry macro PIN_MAP_DUMMY_STATE serves the purpose of defining
+a named state without causing any pin controller to be programmed:
+
+static struct pinctrl_map __initdata mapping[] = {
+ PIN_MAP_DUMMY_STATE("foo-i2c.0", PINCTRL_STATE_DEFAULT),
};
@@ -831,6 +874,7 @@ As it is possible to map a function to different groups of pins an optional
{
.dev_name = "foo-spi.0",
.name = "spi0-pos-A",
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "spi0",
.group = "spi0_0_grp",
@@ -838,6 +882,7 @@ As it is possible to map a function to different groups of pins an optional
{
.dev_name = "foo-spi.0",
.name = "spi0-pos-B",
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "spi0",
.group = "spi0_1_grp",
@@ -857,6 +902,7 @@ case), we define a mapping like this:
{
.dev_name = "foo-mmc.0",
.name = "2bit"
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "mmc0",
.group = "mmc0_1_grp",
@@ -864,6 +910,7 @@ case), we define a mapping like this:
{
.dev_name = "foo-mmc.0",
.name = "4bit"
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "mmc0",
.group = "mmc0_1_grp",
@@ -871,6 +918,7 @@ case), we define a mapping like this:
{
.dev_name = "foo-mmc.0",
.name = "4bit"
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "mmc0",
.group = "mmc0_2_grp",
@@ -878,6 +926,7 @@ case), we define a mapping like this:
{
.dev_name = "foo-mmc.0",
.name = "8bit"
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "mmc0",
.group = "mmc0_1_grp",
@@ -885,6 +934,7 @@ case), we define a mapping like this:
{
.dev_name = "foo-mmc.0",
.name = "8bit"
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "mmc0",
.group = "mmc0_2_grp",
@@ -892,6 +942,7 @@ case), we define a mapping like this:
{
.dev_name = "foo-mmc.0",
.name = "8bit"
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "mmc0",
.group = "mmc0_3_grp",
@@ -1014,6 +1065,7 @@ to the pin controller device name, and the state name is PINCTRL_STATE_DEFAULT.
{
.dev_name = "pinctrl-foo",
.name = PINCTRL_STATE_DEFAULT,
+ .type = PIN_MAP_TYPE_MUX_GROUP,
.ctrl_dev_name = "pinctrl-foo",
.function = "power_func",
},
@@ -1022,7 +1074,7 @@ Since it may be common to request the core to hog a few always-applicable
mux settings on the primary pin controller, there is a convenience macro for
this:
-PIN_MAP_SYS_HOG("pinctrl-foo", "power_func")
+PIN_MAP_MUX_GROUP_HOG_DEFAULT("pinctrl-foo", NULL /* group */, "power_func")
This gives the exact same result as the above construction.

Privacy Policy