shared/milkymist_buttons/buttons.c

0001 /*  buttons.c
0002  *
0003  *  Buttons driver for the Milkymist One board
0004  *
0005  *  The license and distribution terms for this file may be
0006  *  found in the file LICENSE in this distribution or at
0007  *  http://www.rtems.org/license/LICENSE.
0008  *
0009  *  COPYRIGHT (c) 2011 Sebastien Bourdeauducq
0010  */
0011
0012 #define RTEMS_STATUS_CHECKS_USE_PRINTK
0013
0014 #include <stdlib.h>
0015 #include <stdio.h>
0016 #include <errno.h>
0017 #include <sys/types.h>
0018 #include <rtems.h>
0019 #include <rtems/status-checks.h>
0020 #include <bsp.h>
0021 #include <bsp/irq-generic.h>
0022 #include <rtems/libio.h>
0023 #include "../include/system_conf.h"
0024 #include <bsp/milkymist_buttons.h>
0025
0026 #define DEVICE_NAME "/dev/buttons"
0027
0028 static rtems_id event_q;
0029
0030 static void send_byte(char b)
0031 {
0032   rtems_message_queue_send(event_q, &b, 1);
0033 }
0034
0035 static rtems_isr interrupt_handler(rtems_vector_number n)
0036 {
0037   static unsigned int previous_keys;
0038   unsigned int keys, pushed_keys, released_keys;
0039
0040   keys = MM_READ(MM_GPIO_IN) & (GPIO_BTN1|GPIO_BTN2|GPIO_BTN3);
0041   pushed_keys = keys & ~previous_keys;
0042   released_keys = previous_keys & ~keys;
0043   previous_keys = keys;
0044
0045   if(pushed_keys & GPIO_BTN1)
0046     send_byte('A');
0047   if(pushed_keys & GPIO_BTN2)
0048     send_byte('B');
0049   if(pushed_keys & GPIO_BTN3)
0050     send_byte('C');
0051
0052   if(released_keys & GPIO_BTN1)
0053     send_byte('a');
0054   if(released_keys & GPIO_BTN2)
0055     send_byte('b');
0056   if(released_keys & GPIO_BTN3)
0057     send_byte('c');
0058
0059   lm32_interrupt_ack(1 << MM_IRQ_GPIO);
0060 }
0061
0062 rtems_device_driver buttons_initialize(
0063   rtems_device_major_number major,
0064   rtems_device_minor_number minor,
0065   void *arg
0066 )
0067 {
0068   rtems_status_code sc;
0069   rtems_isr_entry dummy;
0070
0071   sc = rtems_io_register_name(DEVICE_NAME, major, 0);
0072   RTEMS_CHECK_SC(sc, "create buttons device");
0073
0074   sc = rtems_message_queue_create(
0075     rtems_build_name('B', 'T', 'N', 'Q'),
0076     24,
0077     1,
0078     0,
0079     &event_q
0080   );
0081   RTEMS_CHECK_SC(sc, "create buttons event queue");
0082
0083   rtems_interrupt_catch(interrupt_handler, MM_IRQ_GPIO, &dummy);
0084   bsp_interrupt_vector_enable(MM_IRQ_GPIO);
0085   MM_WRITE(MM_GPIO_INTEN, GPIO_BTN1|GPIO_BTN2|GPIO_BTN3);
0086
0087   return RTEMS_SUCCESSFUL;
0088 }
0089
0090 rtems_device_driver buttons_open(
0091   rtems_device_major_number major,
0092   rtems_device_minor_number minor,
0093   void *arg
0094 )
0095 {
0096   uint32_t count;
0097
0098   rtems_message_queue_flush(event_q, &count);
0099   return RTEMS_SUCCESSFUL;
0100 }
0101
0102 rtems_device_driver buttons_read(
0103   rtems_device_major_number major,
0104   rtems_device_minor_number minor,
0105   void *arg
0106 )
0107 {
0108   rtems_libio_rw_args_t *rw_args = (rtems_libio_rw_args_t *)arg;
0109   rtems_status_code sc;
0110
0111   if(rw_args->count < 1) {
0112     rw_args->bytes_moved = 0;
0113     return RTEMS_UNSATISFIED;
0114   }
0115
0116   sc = rtems_message_queue_receive(
0117     event_q,
0118     rw_args->buffer,
0119     (size_t *)&rw_args->bytes_moved,
0120     RTEMS_WAIT,
0121     RTEMS_NO_TIMEOUT
0122   );
0123
0124   if(sc == RTEMS_SUCCESSFUL)
0125     return RTEMS_SUCCESSFUL;
0126   else {
0127     rw_args->bytes_moved = 0;
0128     return RTEMS_UNSATISFIED;
0129   }
0130 }