Keychron Q3 I2C & CKLED2001 transfer speedup (qmk#18780)

drivers/led/ckled2001.c

@@ -36,7 +36,7 @@
 #endif
 
 // Transfer buffer for TWITransmitData()
-uint8_t g_twi_transfer_buffer[20];
+uint8_t g_twi_transfer_buffer[65];
 
 // These buffers match the CKLED2001 PWM registers.
 // The control buffers match the PG0 LED On/Off registers.
@@ -72,27 +72,26 @@ bool CKLED2001_write_register(uint8_t addr, uint8_t reg, uint8_t data) {
 bool CKLED2001_write_pwm_buffer(uint8_t addr, uint8_t *pwm_buffer) {
     // Assumes PG1 is already selected.
     // If any of the transactions fails function returns false.
-    // Transmit PWM registers in 12 transfers of 16 bytes.
-    // g_twi_transfer_buffer[] is 20 bytes
+    // Transmit PWM registers in 3 transfers of 64 bytes.
 
-    // Iterate over the pwm_buffer contents at 16 byte intervals.
-    for (int i = 0; i < 192; i += 16) {
+    // Iterate over the pwm_buffer contents at 64 byte intervals.
+    for (uint8_t i = 0; i < 192; i += 64) {
         g_twi_transfer_buffer[0] = i;
-        // Copy the data from i to i+15.
+        // Copy the data from i to i+63.
         // Device will auto-increment register for data after the first byte
         // Thus this sets registers 0x00-0x0F, 0x10-0x1F, etc. in one transfer.
-        for (int j = 0; j < 16; j++) {
+        for (uint8_t j = 0; j < 64; j++) {
             g_twi_transfer_buffer[1 + j] = pwm_buffer[i + j];
         }
 
 #if CKLED2001_PERSISTENCE > 0
         for (uint8_t i = 0; i < CKLED2001_PERSISTENCE; i++) {
-            if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 17, CKLED2001_TIMEOUT) != 0) {
+            if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 65, CKLED2001_TIMEOUT) != 0) {
                 return false;
             }
         }
 #else
-        if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 17, CKLED2001_TIMEOUT) != 0) {
+        if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 65, CKLED2001_TIMEOUT) != 0) {
             return false;
         }
 #endif

keyboards/keychron/q3/config.h

@@ -31,6 +31,13 @@
 #define DRIVER_ADDR_1 0b1110111
 #define DRIVER_ADDR_2 0b1110100
 
+/* Increase I2C speed to 1000 KHz */
+#define I2C1_TIMINGR_PRESC 0U
+#define I2C1_TIMINGR_SCLDEL 3U
+#define I2C1_TIMINGR_SDADEL 0U
+#define I2C1_TIMINGR_SCLH 15U
+#define I2C1_TIMINGR_SCLL 51U
+
 /* Scan phase of led driver set as MSKPHASE_9CHANNEL(defined as 0x03 in CKLED2001.h) */
 #define PHASE_CHANNEL MSKPHASE_9CHANNEL