diff options
Diffstat (limited to 'Documentation/pinctrl.txt')
| -rw-r--r-- | Documentation/pinctrl.txt | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt index b04cb7d45a1..0a8b2250062 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", }, ... |