diff options
| -rw-r--r-- | drivers/tty/serial/atmel_serial.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index e3e14cb7668b..acbf6b82d687 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -150,6 +150,7 @@ struct atmel_uart_port { u32 rts_low; bool ms_irq_enabled; u32 rtor; /* address of receiver timeout register if it exists */ + bool is_usart; bool has_frac_baudrate; bool has_hw_timer; struct timer_list uart_timer; @@ -1825,6 +1826,7 @@ static void atmel_get_ip_name(struct uart_port *port) */ atmel_port->has_frac_baudrate = false; atmel_port->has_hw_timer = false; + atmel_port->is_usart = false; if (name == new_uart) { dev_dbg(port->dev, "Uart with hw timer"); @@ -1834,6 +1836,7 @@ static void atmel_get_ip_name(struct uart_port *port) dev_dbg(port->dev, "Usart\n"); atmel_port->has_frac_baudrate = true; atmel_port->has_hw_timer = true; + atmel_port->is_usart = true; atmel_port->rtor = ATMEL_US_RTOR; version = atmel_uart_readl(port, ATMEL_US_VERSION); switch (version) { @@ -1863,6 +1866,7 @@ static void atmel_get_ip_name(struct uart_port *port) dev_dbg(port->dev, "This version is usart\n"); atmel_port->has_frac_baudrate = true; atmel_port->has_hw_timer = true; + atmel_port->is_usart = true; atmel_port->rtor = ATMEL_US_RTOR; break; case 0x203: @@ -2286,10 +2290,21 @@ static void atmel_set_termios(struct uart_port *port, cd = uart_get_divisor(port, baud); } - if (cd > 65535) { /* BRGR is 16-bit, so switch to slower clock */ + /* + * If the current value of the Clock Divisor surpasses the 16 bit + * ATMEL_US_CD mask and the IP is USART, switch to the Peripheral + * Clock implicitly divided by 8. + * If the IP is UART however, keep the highest possible value for + * the CD and avoid needless division of CD, since UART IP's do not + * support implicit division of the Peripheral Clock. + */ + if (atmel_port->is_usart && cd > ATMEL_US_CD) { cd /= 8; mode |= ATMEL_US_USCLKS_MCK_DIV8; + } else { + cd = min_t(unsigned int, cd, ATMEL_US_CD); } + quot = cd | fp << ATMEL_US_FP_OFFSET; if (!(port->iso7816.flags & SER_ISO7816_ENABLED)) |