lpc176x: Enable full speed peripheral clocks on SPI and I2C

Scale the bus speed within the peripheral instead of on the system bus
as scaling on the system bus slows down general register access to the
peripheral.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/lpc176x/spi.c b/src/lpc176x/spi.c
index 92e303d0..8373a39f 100644
--- a/src/lpc176x/spi.c
+++ b/src/lpc176x/spi.c
@@ -23,6 +23,9 @@ spi_init(void)
     gpio_peripheral(0, 17, 2, 0);
     gpio_peripheral(0, 18, 2, 0);
 
+    // Setup clock
+    enable_peripheral_clock(PCLK_SSP0);
+
     // Set initial registers
     LPC_SSP0->CR0 = 0x07;
     LPC_SSP0->CPSR = 254;
@@ -40,7 +43,7 @@ spi_setup(uint32_t bus, uint8_t mode, uint32_t rate)
 
     // Setup clock rate and mode
     struct spi_config res = {0, 0};
-    uint32_t pclk = SystemCoreClock / 4;
+    uint32_t pclk = SystemCoreClock;
     uint32_t div = DIV_ROUND_UP(pclk/2, rate) << 1;
     res.cpsr = div < 2 ? 2 : (div > 254 ? 254 : div);
     res.cr0 = 0x07 | (mode << 6);