The dollar firmed against the yen on Friday on the back of rising U.S. Treasury yields, as optimism over debt ceiling talks in Washington raised expectations of higher-for-longer interest rates. President Joe Biden and top U.S. congressional Republican Kevin McCarthy earlier this week underscored their determination to strike a deal soon to raise the government's $31.4 trillion debt ceiling, with hopes of finalising a deal after Biden returns from the Group of Seven meeting in Japan on Sunday