Fix issue with ppkb inputd not working after using the kernel driver

This was caused by kernel driver disabling the matrix scan in the KB
firmware and userspace tools not re-enabling it on startup. :)

i2c-inputd.c

@@ -61,11 +61,35 @@ int read_kb(int fd, uint8_t data[16])
 	return ret == 2 ? 0 : -1;
 }
 
-int write_kb(int fd, uint8_t* data)
+int read_kb_reg(int fd, uint8_t reg, uint8_t* data)
 {
 	int ret;
+
+	struct i2c_msg msgs[] = {
+		{ KB_ADDR, 0, 1, &reg },
+		{ KB_ADDR, I2C_M_RD, 1, data },
+	};
+
+	struct i2c_rdwr_ioctl_data msg = {
+		.msgs = msgs,
+		.nmsgs = sizeof(msgs) / sizeof(msgs[0])
+	};
+
+	ret = ioctl(fd, I2C_RDWR, &msg);
+	if (ret < 0) {
+		printf("WARNING: I2C_RDWR failed (%d)\n", errno);
+		return -1;
+	}
+	
+	return ret == 2 ? 0 : -1;
+}
+
+int write_kb_reg(int fd, uint8_t reg, uint8_t data)
+{
+	int ret;
+	uint8_t buf[2] = {reg, data};
 	struct i2c_msg msgs[] = {
-		{ KB_ADDR, 0, 4, data },
+		{ KB_ADDR, 0, 2, buf },
 	};
 
 	struct i2c_rdwr_ioctl_data msg = {
@@ -318,8 +342,15 @@ int main(int ac, char* av[])
 
 	debug("\033[2J");
 
-//	uint8_t buf[4] = {1, 2, 3, 4};
-//	ret = write_kb(fd, buf);
+	uint8_t val;
+
+	ret = read_kb_reg(fd, REG_SYS_CONFIG, &val);
+	syscall_error(ret < 0, "read_kb_reg(PPKB_SYS_CONFIG) failed");
+        
+        val &= ~REG_SYS_CONFIG_SCAN_BLOCK;
+
+	ret = write_kb_reg(fd, REG_SYS_CONFIG, val);
+	syscall_error(ret < 0, "write_kb_reg(PPKB_SYS_CONFIG) failed");
 
 	// - we rely on POGO interrupt to get the key updates
 	// - if any key is pressed, we will in addition poll