SDL: Allow the application to send commands to Nintendo Switch controllers

SDL Commits
1 
From 9837653b9d20d48b30caa66f93951b8604e7e9ea Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Fri, 2 Jun 2023 15:52:56 -0700
Subject: [PATCH] Allow the application to send commands to Nintendo Switch
 controllers

---
 src/joystick/hidapi/SDL_hidapi_switch.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/joystick/hidapi/SDL_hidapi_switch.c b/src/joystick/hidapi/SDL_hidapi_switch.c
index b51f961c504a..289555ace8e8 100644
--- a/src/joystick/hidapi/SDL_hidapi_switch.c
+++ b/src/joystick/hidapi/SDL_hidapi_switch.c
@@ -393,7 +393,7 @@ static SDL_bool ReadProprietaryReply(SDL_DriverSwitch_Context *ctx, ESwitchPropr
     return SDL_FALSE;
 }
 
-static void ConstructSubcommand(SDL_DriverSwitch_Context *ctx, ESwitchSubcommandIDs ucCommandID, Uint8 *pBuf, Uint8 ucLen, SwitchSubcommandOutputPacket_t *outPacket)
+static void ConstructSubcommand(SDL_DriverSwitch_Context *ctx, ESwitchSubcommandIDs ucCommandID, const Uint8 *pBuf, Uint8 ucLen, SwitchSubcommandOutputPacket_t *outPacket)
 {
     SDL_memset(outPacket, 0, sizeof(*outPacket));
 
@@ -432,7 +432,7 @@ static SDL_bool WritePacket(SDL_DriverSwitch_Context *ctx, void *pBuf, Uint8 ucL
     }
 }
 
-static SDL_bool WriteSubcommand(SDL_DriverSwitch_Context *ctx, ESwitchSubcommandIDs ucCommandID, Uint8 *pBuf, Uint8 ucLen, SwitchSubcommandInputPacket_t **ppReply)
+static SDL_bool WriteSubcommand(SDL_DriverSwitch_Context *ctx, ESwitchSubcommandIDs ucCommandID, const Uint8 *pBuf, Uint8 ucLen, SwitchSubcommandInputPacket_t **ppReply)
 {
     SwitchSubcommandInputPacket_t *reply = NULL;
     int nTries;
@@ -648,7 +648,7 @@ static SDL_bool SetVibrationEnabled(SDL_DriverSwitch_Context *ctx, Uint8 enabled
 }
 static SDL_bool SetInputMode(SDL_DriverSwitch_Context *ctx, Uint8 input_mode)
 {
-    return WriteSubcommand(ctx, k_eSwitchSubcommandIDs_SetInputReportMode, &input_mode, 1, NULL);
+    return WriteSubcommand(ctx, k_eSwitchSubcommandIDs_SetInputReportMode, &input_mode, sizeof(input_mode), NULL);
 }
 
 static SDL_bool SetHomeLED(SDL_DriverSwitch_Context *ctx, Uint8 brightness)
@@ -1579,6 +1579,19 @@ static int HIDAPI_DriverSwitch_SendJoystickEffect(SDL_HIDAPI_Device *device, SDL
         ctx->m_bRumblePending = SDL_FALSE;
         ctx->m_bRumbleZeroPending = SDL_FALSE;
         return 0;
+    } else if (size >= 2 && size <= 256) {
+        const Uint8 *payload = (const Uint8 *)data;
+        ESwitchSubcommandIDs cmd = (ESwitchSubcommandIDs)payload[0];
+
+        if (cmd == k_eSwitchSubcommandIDs_SetInputReportMode && !device->is_bluetooth) {
+            /* Going into simple mode over USB disables input reports, so don't do that */
+            return 0;
+        }
+
+        if (!WriteSubcommand(ctx, cmd, &payload[1], (Uint8)(size - 1), NULL)) {
+            return -1;
+        }
+        return 0;
     }
     return SDL_Unsupported();
 }