Lines Matching +full:signal +full:- +full:group
5 -----------------
7 GPIO properties should be named "[<name>-]gpios", with <name> being the purpose
8 of this GPIO for the device. While a non-existent <name> is considered valid
10 for new bindings. Also, GPIO properties named "[<name>-]gpio" are valid and old
24 and bit-banged data signals:
27 gpio-controller;
28 #gpio-cells = <2>;
32 data-gpios = <&gpio1 12 0>,
44 recommended to use the two-cell approach.
48 include/dt-bindings/gpio/gpio.h whenever possible:
53 enable-gpios = <&qe_pio_e 18 GPIO_ACTIVE_HIGH>;
56 GPIO_ACTIVE_HIGH is 0, so in this example gpio-specifier is "18 0" and encodes
57 GPIO pin number, and GPIO flags as accepted by the "qe_pio_e" gpio-controller.
61 - Bit 0: 0 means active high, 1 means active low
62 - Bit 1: 0 mean push-pull wiring, see:
63 https://en.wikipedia.org/wiki/Push-pull_output
64 1 means single-ended wiring, see:
65 https://en.wikipedia.org/wiki/Single-ended_triode
66 - Bit 2: 0 means open-source, 1 means open drain, see:
68 - Bit 3: 0 means the output should be maintained during sleep/low-power mode
69 1 means the output state can be lost during sleep/low-power mode
70 - Bit 4: 0 means no pull-up resistor should be enabled
71 1 means a pull-up resistor should be enabled
73 control for pull-up configuration. If the hardware has more
74 elaborate pull-up configuration, it should be represented
76 - Bit 5: 0 means no pull-down resistor should be enabled
77 1 means a pull-down resistor should be enabled
79 control for pull-down configuration. If the hardware has more
80 elaborate pull-down configuration, it should be represented
84 ----------------------------------
86 A gpio-specifier should contain a flag indicating the GPIO polarity; active-
87 high or active-low. If it does, the following best practices should be
90 The gpio-specifier's polarity flag should represent the physical level at the
93 defined by the binding for the device. If the board inverts the signal between
94 the GPIO controller and the device, then the gpio-specifier will represent the
95 opposite physical level than the signal at the device's pin.
97 When the device's signal polarity is configurable, the binding for the
100 a) Define a single static polarity for the signal, with the expectation that
102 that signal polarity.
106 a1) (Preferred) Dictated by a binding-specific DT property.
112 In particular, the polarity cannot be derived from the gpio-specifier, since
114 concepts of configurable signal polarity in the device, and possible board-
115 level signal inversion.
119 b) Pick a single option for device signal polarity, and document this choice
120 in the binding. The gpio-specifier should represent the polarity of the signal
122 particular signal polarity choice. If software chooses to program the device
123 to generate or receive a signal of the opposite polarity, software will be
124 responsible for correctly interpreting (inverting) the GPIO signal at the GPIO
127 2) gpio-controller nodes
128 ------------------------
130 Every GPIO controller node must contain both an empty "gpio-controller"
131 property, and a #gpio-cells integer property, which indicates the number of
132 cells in a gpio-specifier.
134 Some system-on-chips (SoCs) use the concept of GPIO banks. A GPIO bank is an
137 exposed in the device tree as an individual gpio-controller node, reflecting
142 indicates the number of in-use slots of available slots for GPIOs. The
150 If these GPIOs do not happen to be the first N GPIOs at offset 0...N-1, an
152 the gpio-reserved-ranges binding. This property indicates the start and size
155 Optionally, a GPIO controller may have a "gpio-line-names" property. This is
161 helpful. For example "MMC-CD", "Red LED Vdd" and "ethernet reset" are
172 gpio-controller@00000000 {
175 gpio-controller;
176 #gpio-cells = <2>;
178 gpio-reserved-ranges = <0 4>, <12 2>;
179 gpio-line-names = "MMC-CD", "MMC-WP", "VDD eth", "RST eth", "LED R",
187 gpio-controller's driver probe function.
191 - gpio-hog: A property specifying that this child node represents a GPIO hog.
192 - gpios: Store the GPIO information (id, flags, ...) for each GPIO to
199 - input: A property specifying to set the GPIO direction as input.
200 - output-low A property specifying to set the GPIO direction as output with
202 - output-high A property specifying to set the GPIO direction as output with
206 - line-name: The GPIO label name. If not present the node name is used.
208 Example of two SOC GPIO banks defined as gpio-controller nodes:
210 qe_pio_a: gpio-controller@1400 {
211 compatible = "fsl,qe-pario-bank-a", "fsl,qe-pario-bank";
213 gpio-controller;
214 #gpio-cells = <2>;
216 line_b-hog {
217 gpio-hog;
219 output-low;
220 line-name = "foo-bar-gpio";
224 qe_pio_e: gpio-controller@1460 {
225 compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
227 gpio-controller;
228 #gpio-cells = <2>;
231 2.1) gpio- and pin-controller interaction
232 -----------------------------------------
240 -------------------------------------
243 controllers. The gpio-ranges property described below represents this with
254 described in pinctrl/pinctrl-bindings.txt.
257 ranges with just one pin-to-GPIO line mapping if the ranges are concocted, but
262 gpio-ranges = <&foo 0 20 10>, <&bar 10 50 20>;
265 - pins 20..29 on pin controller "foo" is mapped to GPIO line 0..9 and
266 - pins 50..69 on pin controller "bar" is mapped to GPIO line 10..29
271 qe_pio_e: gpio-controller@1460 {
272 #gpio-cells = <2>;
273 compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
275 gpio-controller;
276 gpio-ranges = <&pinctrl1 0 20 10>, <&pinctrl2 10 50 20>;
285 --------------------------------------
290 Both both <pinctrl-base> and <count> must set to 0 when using named pin groups
293 The property gpio-ranges-group-names must contain exactly one string for each
296 Elements of gpio-ranges-group-names must contain the name of a pin group
298 range is the number of pins in that pin group. The number of pins of that
299 group is defined int the implementation and not in the device tree.
302 numerical pin range in gpio-ranges-group-names must be empty.
306 gpio_pio_i: gpio-controller@14b0 {
307 #gpio-cells = <2>;
308 compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
310 gpio-controller;
311 gpio-ranges = <&pinctrl1 0 20 10>,
315 gpio-ranges-group-names = "",
327 were referenced by any gpio-ranges property to contain a property named
328 #gpio-range-cells with value <3>. This requirement is now deprecated.