common/button_cmd.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2023 Linaro Ltd.
   4  *   Author: Caleb Connolly <caleb.connolly@linaro.org>
   5  */
   6
   7 #include <button.h>
   8 #include <command.h>
   9 #include <env.h>
  10 #include <log.h>
  11 #include <vsprintf.h>
  12
  13 /* Some sane limit "just in case" */
  14 #define MAX_BTN_CMDS 32
  15
  16 struct button_cmd {
  17         bool pressed;
  18         const char *btn_name;
  19         const char *cmd;
  20 };
  21
  22 /*
  23  * Button commands are set via environment variables, e.g.:
  24  * button_cmd_N_name=Volume Up
  25  * button_cmd_N=fastboot usb 0
  26  *
  27  * This function will retrieve the command for the given button N
  28  * and populate the cmd struct with the command string and pressed
  29  * state of the button.
  30  *
  31  * Returns 1 if a command was found, 0 otherwise.
  32  */
  33 static int get_button_cmd(int n, struct button_cmd *cmd)
  34 {
  35         const char *cmd_str;
  36         struct udevice *btn = NULL;
  37         char buf[24];
  38
  39         snprintf(buf, sizeof(buf), "button_cmd_%d_name", n);
  40         cmd->btn_name = env_get(buf);
  41         if (!cmd->btn_name)
  42                 return 0;
  43
  44         button_get_by_label(cmd->btn_name, &btn);
  45         if (!btn) {
  46                 log_err("No button labelled '%s'\n", cmd->btn_name);
  47                 return 0;
  48         }
  49
  50         cmd->pressed = button_get_state(btn) == BUTTON_ON;
  51         /* If the button isn't pressed then cmd->cmd will be unused so don't waste
  52          * cycles reading it
  53          */
  54         if (!cmd->pressed)
  55                 return 1;
  56
  57         snprintf(buf, sizeof(buf), "button_cmd_%d", n);
  58         cmd_str = env_get(buf);
  59         if (!cmd_str) {
  60                 log_err("No command set for button '%s'\n", cmd->btn_name);
  61                 return 0;
  62         }
  63
  64         cmd->cmd = cmd_str;
  65
  66         return 1;
  67 }
  68
  69 void process_button_cmds(void)
  70 {
  71         struct button_cmd cmd = {0};
  72         int i = 0;
  73
  74         while (get_button_cmd(i++, &cmd) && i < MAX_BTN_CMDS) {
  75                 if (!cmd.pressed)
  76                         continue;
  77
  78                 log_info("BTN '%s'> %s\n", cmd.btn_name, cmd.cmd);
  79                 run_command(cmd.cmd, CMD_FLAG_ENV);
  80                 /* Don't run commands for multiple buttons */
  81                 return;
  82         }
  83 }