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@ti.com>
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Reported-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
index b04cb7d45a1632625a194883587b1300690a200c..f78ebce09b9b9fb9cdb0ec8d2026f9bbb010fdcc 100644 (file)
--- 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
@@ -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,
@@ -606,7 +606,7 @@ int foo_enable(struct pinctrl_dev *pctldev, unsigned selector,
        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);
@@ -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 c77aee5508fbc97e843be0dacb9d6e20ab3fc6f1..092382452ed6a5b067373986c183ce05f8e4323b 100644 (file)
--- 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)