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serial: max310x: Fix tx_empty() callback

Function max310x_tx_empty() accesses the IRQSTS register, which is
cleared by IC when reading, so if there is an interrupt status, we
will lose it. This patch implement the transmitter check only by
the current FIFO level.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Alexander Shiyan 2018-12-19 14:19:20 +03:00 committed by Greg Kroah-Hartman
parent a88c4736ea
commit a8da3c7873
1 changed files with 2 additions and 5 deletions

View File

@ -833,12 +833,9 @@ static void max310x_wq_proc(struct work_struct *ws)
static unsigned int max310x_tx_empty(struct uart_port *port)
{
unsigned int lvl, sts;
u8 lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
sts = max310x_port_read(port, MAX310X_IRQSTS_REG);
return ((sts & MAX310X_IRQ_TXEMPTY_BIT) && !lvl) ? TIOCSER_TEMT : 0;
return lvl ? 0 : TIOCSER_TEMT;
}
static unsigned int max310x_get_mctrl(struct uart_port *port)