diff --git a/src/tpi.h b/src/tpi.h
index 88c548d2..b6c0a291 100644
--- a/src/tpi.h
+++ b/src/tpi.h
@@ -23,9 +23,11 @@
 extern "C" {
 #endif
 
-static const unsigned char tpi_skey[] = { 0x12, 0x89, 0xAB, 0x45, 0xCD, 0xD8, 0x88, 0xFF };
+static const unsigned char tpi_skey[] = {
+  0x12, 0x89, 0xAB, 0x45, 0xCD, 0xD8, 0x88, 0xFF
+};
 
-/* registers */
+// Registers
 #define TPI_REG_TPIIR  0x0F
 
 #define TPI_IDENT_CODE 0x80
@@ -33,42 +35,42 @@ static const unsigned char tpi_skey[] = { 0x12, 0x89, 0xAB, 0x45, 0xCD, 0xD8, 0x
 #define TPI_REG_TPIPCR 0x02
 #define TPI_REG_TPISR  0x00
 
-#define TPI_REG_TPISR_NVMEN		(1 << 1)
+#define TPI_REG_TPISR_NVMEN (1<<1)
 
-/* TPI commands */
-#define TPI_CMD_SLD		0x20
-#define TPI_CMD_SLD_PI	0x24
-#define TPI_CMD_SIN		0x10
-#define TPI_CMD_SOUT	0x90
-#define TPI_CMD_SSTCS	0xC0
-#define TPI_CMD_SST		0x60
-#define TPI_CMD_SST_PI	0x64
+// TPI commands
+#define TPI_CMD_SLD        0x20
+#define TPI_CMD_SLD_PI     0x24
+#define TPI_CMD_SIN        0x10
+#define TPI_CMD_SOUT       0x90
+#define TPI_CMD_SSTCS      0xC0
+#define TPI_CMD_SST        0x60
+#define TPI_CMD_SST_PI     0x64
 
-#define TPI_CMD_SLDCS	0x80
-#define TPI_CMD_SSTPR	0x68
-#define TPI_CMD_SKEY	0xE0
+#define TPI_CMD_SLDCS      0x80
+#define TPI_CMD_SSTPR      0x68
+#define TPI_CMD_SKEY       0xE0
 
-/* for TPI_CMD_SIN & TPI_CMD_SOUT */
-#define TPI_SIO_ADDR(x) ((x & 0x30) << 1 | (x & 0x0F)) 
+// For TPI_CMD_SIN & TPI_CMD_SOUT
+#define TPI_SIO_ADDR(x) ((x & 0x30) << 1 | (x & 0x0F))
 
-/* ATtiny4/5/9/10 I/O registers */
-#define TPI_IOREG_NVMCSR		0x32
-#define TPI_IOREG_NVMCMD		0x33
+// ATtiny4/5/9/10 I/O registers
+#define TPI_IOREG_NVMCSR   0x32
+#define TPI_IOREG_NVMCMD   0x33
 
-/* bit for NVMCSR */
-#define TPI_IOREG_NVMCSR_NVMBSY	(1 << 7)
+// Bit for NVMCSR
+#define TPI_IOREG_NVMCSR_NVMBSY (1<<7)
 
-/* NVM commands */
-#define TPI_NVMCMD_NO_OPERATION		0x00
-#define TPI_NVMCMD_CHIP_ERASE		0x10
-#define TPI_NVMCMD_SECTION_ERASE	0x14
-#define TPI_NVMCMD_WORD_WRITE		0x1D
+// NVM commands
+#define TPI_NVMCMD_NO_OPERATION  0x00
+#define TPI_NVMCMD_CHIP_ERASE    0x10
+#define TPI_NVMCMD_SECTION_ERASE 0x14
+#define TPI_NVMCMD_WORD_WRITE    0x1D
 
-static const unsigned char tpi_skey_cmd[] = { TPI_CMD_SKEY, 0xff, 0x88, 0xd8, 0xcd, 0x45, 0xab, 0x89, 0x12 };
+static const unsigned char tpi_skey_cmd[] = {
+  TPI_CMD_SKEY, 0xff, 0x88, 0xd8, 0xcd, 0x45, 0xab, 0x89, 0x12
+};
 
 #ifdef __cplusplus
 }
 #endif
-
 #endif
-