};
-static int foo_list_groups(struct pinctrl_dev *pctldev, unsigned selector)
+static int foo_get_groups_count(struct pinctrl_dev *pctldev)
{
- if (selector >= ARRAY_SIZE(foo_groups))
- return -EINVAL;
- return 0;
+ return ARRAY_SIZE(foo_groups);
}
static const char *foo_get_group_name(struct pinctrl_dev *pctldev,
}
static struct pinctrl_ops foo_pctrl_ops = {
- .list_groups = foo_list_groups,
+ .get_groups_count = foo_get_groups_count,
.get_group_name = foo_get_group_name,
.get_group_pins = foo_get_group_pins,
};
.pctlops = &foo_pctrl_ops,
};
-The pin control subsystem will call the .list_groups() function repeatedly
-beginning on 0 until it returns non-zero to determine legal selectors, then
-it will call the other functions to retrieve the name and pins of the group.
-Maintaining the data structure of the groups is up to the driver, this is
-just a simple example - in practice you may need more entries in your group
-structure, for example specific register ranges associated with each group
-and so on.
+The pin control subsystem will call the .get_groups_count() function to
+determine total number of legal selectors, then it will call the other functions
+to retrieve the name and pins of the group. Maintaining the data structure of
+the groups is up to the driver, this is just a simple example - in practice you
+may need more entries in your group structure, for example specific register
+ranges associated with each group and so on.
Pin configuration
};
-static int foo_list_groups(struct pinctrl_dev *pctldev, unsigned selector)
+static int foo_get_groups_count(struct pinctrl_dev *pctldev)
{
- if (selector >= ARRAY_SIZE(foo_groups))
- return -EINVAL;
- return 0;
+ return ARRAY_SIZE(foo_groups);
}
static const char *foo_get_group_name(struct pinctrl_dev *pctldev,
}
static struct pinctrl_ops foo_pctrl_ops = {
- .list_groups = foo_list_groups,
+ .get_groups_count = foo_get_groups_count,
.get_group_name = foo_get_group_name,
.get_group_pins = foo_get_group_pins,
};
const unsigned num_groups;
};
-static const char * const spi0_groups[] = { "spi0_1_grp" };
+static const char * const spi0_groups[] = { "spi0_0_grp", "spi0_1_grp" };
static const char * const i2c0_groups[] = { "i2c0_grp" };
static const char * const mmc0_groups[] = { "mmc0_1_grp", "mmc0_2_grp",
"mmc0_3_grp" };
},
};
-int foo_list_funcs(struct pinctrl_dev *pctldev, unsigned selector)
+int foo_get_functions_count(struct pinctrl_dev *pctldev)
{
- if (selector >= ARRAY_SIZE(foo_functions))
- return -EINVAL;
- return 0;
+ return ARRAY_SIZE(foo_functions);
}
const char *foo_get_fname(struct pinctrl_dev *pctldev, unsigned selector)
}
struct pinmux_ops foo_pmxops = {
- .list_functions = foo_list_funcs,
+ .get_functions_count = foo_get_functions_count,
.get_function_name = foo_get_fname,
.get_function_groups = foo_get_groups,
.enable = foo_enable,
#include <linux/pinctrl/machine.h>
-static const struct pinctrl_map __initdata mapping[] = {
+static const struct pinctrl_map mapping[] __initconst = {
{
.dev_name = "foo-spi.0",
.name = PINCTRL_STATE_DEFAULT,
The result of grabbing this mapping from the device with something like
this (see next paragraph):
- p = pinctrl_get(dev);
+ p = devm_pinctrl_get(dev);
s = pinctrl_lookup_state(p, "8bit");
ret = pinctrl_select_state(p, s);
or more simply:
- p = pinctrl_get_select(dev, "8bit");
+ p = devm_pinctrl_get_select(dev, "8bit");
Will be that you activate all the three bottom records in the mapping at
once. Since they share the same name, pin controller device, function and
/* Allocate a state holder named "foo" etc */
struct foo_state *foo = ...;
- foo->p = pinctrl_get(&device);
+ foo->p = devm_pinctrl_get(&device);
if (IS_ERR(foo->p)) {
/* FIXME: clean up "foo" here */
return PTR_ERR(foo->p);
foo->s = pinctrl_lookup_state(foo->p, PINCTRL_STATE_DEFAULT);
if (IS_ERR(foo->s)) {
- pinctrl_put(foo->p);
/* FIXME: clean up "foo" here */
return PTR_ERR(s);
}
ret = pinctrl_select_state(foo->s);
if (ret < 0) {
- pinctrl_put(foo->p);
/* FIXME: clean up "foo" here */
return ret;
}
}
-foo_remove()
-{
- pinctrl_put(state->p);
-}
-
This get/lookup/select/put sequence can just as well be handled by bus drivers
if you don't want each and every driver to handle it and you know the
arrangement on your bus.
kernel memory to hold the pinmux state. All mapping table parsing or similar
slow operations take place within this API.
+- devm_pinctrl_get() is a variant of pinctrl_get() that causes pinctrl_put()
+ to be called automatically on the retrieved pointer when the associated
+ device is removed. It is recommended to use this function over plain
+ pinctrl_get().
+
- pinctrl_lookup_state() is called in process context to obtain a handle to a
specific state for a the client device. This operation may be slow too.
- pinctrl_put() frees all information associated with a pinctrl handle.
+- devm_pinctrl_put() is a variant of pinctrl_put() that may be used to
+ explicitly destroy a pinctrl object returned by devm_pinctrl_get().
+ However, use of this function will be rare, due to the automatic cleanup
+ that will occur even without calling it.
+
+ pinctrl_get() must be paired with a plain pinctrl_put().
+ pinctrl_get() may not be paired with devm_pinctrl_put().
+ devm_pinctrl_get() can optionally be paired with devm_pinctrl_put().
+ devm_pinctrl_get() may not be paired with plain pinctrl_put().
+
Usually the pin control core handled the get/put pair and call out to the
device drivers bookkeeping operations, like checking available functions and
the associated pins, whereas the enable/disable pass on to the pin controller
driver which takes care of activating and/or deactivating the mux setting by
quickly poking some registers.
-The pins are allocated for your device when you issue the pinctrl_get() call,
-after this you should be able to see this in the debugfs listing of all pins.
+The pins are allocated for your device when you issue the devm_pinctrl_get()
+call, after this you should be able to see this in the debugfs listing of all
+pins.
+
+NOTE: the pinctrl system will return -EPROBE_DEFER if it cannot find the
+requested pinctrl handles, for example if the pinctrl driver has not yet
+registered. Thus make sure that the error path in your driver gracefully
+cleans up and is ready to retry the probing later in the startup process.
System pin control hogging
#include <linux/pinctrl/consumer.h>
-foo_switch()
-{
- struct pinctrl *p;
- struct pinctrl_state *s1, *s2;
+struct pinctrl *p;
+struct pinctrl_state *s1, *s2;
+foo_probe()
+{
/* Setup */
- p = pinctrl_get(&device);
+ p = devm_pinctrl_get(&device);
if (IS_ERR(p))
...
s2 = pinctrl_lookup_state(foo->p, "pos-B");
if (IS_ERR(s2))
...
+}
+foo_switch()
+{
/* Enable on position A */
ret = pinctrl_select_state(s1);
if (ret < 0)
...
...
-
- pinctrl_put(p);
}
The above has to be done from process context.