| From 0024e9d897c93838a7e5433a3b51610f58c41432 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 25 Jun 2021 00:49:01 +0200 |
| Subject: serial: mvebu-uart: do not allow changing baudrate when uartclk is |
| not available |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| From: Pali Rohár <pali@kernel.org> |
| |
| [ Upstream commit ecd6b010d81f97b06b2f64d2d4f50ebf5acddaa9 ] |
| |
| Testing mvuart->clk for non-error is not enough as mvuart->clk may contain |
| valid clk pointer but when clk_prepare_enable(mvuart->clk) failed then |
| port->uartclk is zero. |
| |
| When mvuart->clk is not available then port->uartclk is zero too. |
| |
| Parent clock rate port->uartclk is needed to calculate UART clock divisor |
| and without it is not possible to change baudrate. |
| |
| So fix test condition when it is possible to change baudrate. |
| |
| Signed-off-by: Pali Rohár <pali@kernel.org> |
| Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate") |
| Link: https://lore.kernel.org/r/20210624224909.6350-3-pali@kernel.org |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/tty/serial/mvebu-uart.c | 5 ++--- |
| 1 file changed, 2 insertions(+), 3 deletions(-) |
| |
| diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c |
| index 908a4ac6b5a7..9638ae6aae79 100644 |
| --- a/drivers/tty/serial/mvebu-uart.c |
| +++ b/drivers/tty/serial/mvebu-uart.c |
| @@ -445,12 +445,11 @@ static void mvebu_uart_shutdown(struct uart_port *port) |
| |
| static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud) |
| { |
| - struct mvebu_uart *mvuart = to_mvuart(port); |
| unsigned int d_divisor, m_divisor; |
| u32 brdv, osamp; |
| |
| - if (IS_ERR(mvuart->clk)) |
| - return -PTR_ERR(mvuart->clk); |
| + if (!port->uartclk) |
| + return -EOPNOTSUPP; |
| |
| /* |
| * The baudrate is derived from the UART clock thanks to two divisors: |
| -- |
| 2.30.2 |
| |