patacongo edited a comment on pull request #1832:
URL: https://github.com/apache/incubator-nuttx/pull/1832#issuecomment-694431378
>
>
> @patacongo does this definition make sense for `STMPE811_GPIO_PIN(n)` I
would expect to do something like this to define the pin config:
>
> ```
> #define KB_FW_BL (STMPE811_GPIO_OUTPUT | STMPE811_GPIO_PIN(3))
> ```
>
> But that sets the bit shift in the register not pin config. Instead I have
to do something like this:
>
> ```
> #define KB_FW_BL (STMPE811_GPIO_OUTPUT | STMPE811_GPIO_PIN3)
> ```
>
> That seems inconsistent to me with how we normally set GPIO pincfg.
What is there seems correct to me. The encoding is "Bits 0-2 is the pin
number". For:
#define KB_FW_BL (STMPE811_GPIO_OUTPUT | STMPE811_GPIO_PIN3)
That would be Bits 0-2 == 0b011. For:
#define KB_FW_BL (STMPE811_GPIO_OUTPUT | STMPE811_GPIO_PIN(3))
STMPE811_GPIO_PIN(3) ix 0b1000 sowhich would not fit into Bits 0-2 and would
clobber Bit 3: "Bit 3 is the initial value for output pins"
This is the full encoding:
389 /* The STMPE811 GPIO interfaces take an 8-bit bit-encoded parameter
to describe the GPIO pin.
390 * The following definitions describe the bit-encoding of that
parameter.
391 *
392 * 7654 3210
393 * ---- ----
394 * DIRF VPPP
395 *
396 * Input Pins: 1IRF .PPP
397 *
398 * Output Pins: 0... VPPP
399 *
400 * Bits 7 is the pin direction.
401 */
407 /* Bit 6 indicates that the pin will generate an interrupt (inputs
only) */
411 /* The bits 4-5 select the rising and/or the falling edge detection.
*/
416 /* Bit 3 is the initial value for output pins */
422 /* Bits 0-2 is the pin number */
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