From 3c089d7ebfcb31ad6fb0530970a32303b1168991 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Fri, 3 May 2024 20:16:03 +0300 Subject: serial: 8250_exar: Use BIT() in exar_ee_read() Use BIT() in exar_ee_read() like other functions do. While at it, explain the EEPROM type and the dummy bit requirement. Signed-off-by: Andy Shevchenko Tested-by: Parker Newman Link: https://lore.kernel.org/r/20240503171917.2921250-12-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_exar.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c index 306bc6d7c141..93d2c8dd3cd8 100644 --- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -324,6 +324,7 @@ static inline u8 exar_ee_read_bit(struct exar8250 *priv) * @ee_addr: Offset of EEPROM to read word from * * Read a single 16bit word from an Exar UART's EEPROM. + * The type of the EEPROM is AT93C46D. * * Return: EEPROM word */ @@ -340,13 +341,13 @@ static u16 exar_ee_read(struct exar8250 *priv, u8 ee_addr) exar_ee_write_bit(priv, 0); // Send address to read from - for (i = 1 << (UART_EXAR_REGB_EE_ADDR_SIZE - 1); i; i >>= 1) - exar_ee_write_bit(priv, (ee_addr & i)); + for (i = UART_EXAR_REGB_EE_ADDR_SIZE - 1; i >= 0; i--) + exar_ee_write_bit(priv, ee_addr & BIT(i)); - // Read data 1 bit at a time - for (i = 0; i <= UART_EXAR_REGB_EE_DATA_SIZE; i++) { - data <<= 1; - data |= exar_ee_read_bit(priv); + // Read data 1 bit at a time starting with a dummy bit + for (i = UART_EXAR_REGB_EE_DATA_SIZE; i >= 0; i--) { + if (exar_ee_read_bit(priv)) + data |= BIT(i); } exar_ee_deselect(priv); -- cgit v1.2.3