Commit e61c38d85b73 ("serial: imx: setup DCEDTE early and ensure DCD and
RI irqs to be off") has a flaw: While UCR3 and UFCR were modified using
read-modify-write before it switched to write register values
independent of the previous state. That's a good idea in principle (and
that's why I did it) but needs more care.
This patch reinstates read-modify-write for UFCR and for UCR3 ensures
that RXDMUXSEL and ADNIMP are set for post imx1.
Fixes: e61c38d85b73 ("serial: imx: setup DCEDTE early and ensure DCD and RI irqs to be off")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
Hello,
my test machines didn't show a problem with e61c38d85b73 (I guess they
all happen to use UFCR.RFDIV = 0) so I'd like to ask Steve (and Mika) to
test this patch. I only compile tested it for now.
This is a combination of the patch I already posted in respose to Mika's
regression report and the insights I got from Steve's testing.
Best regards
Uwe
drivers/tty/serial/imx.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 33509b4beaec..bbefddd92bfe 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2184,7 +2184,9 @@ static int serial_imx_probe(struct platform_device *pdev)
* and DCD (when they are outputs) or enables the respective
* irqs. So set this bit early, i.e. before requesting irqs.
*/
- writel(UFCR_DCEDTE, sport->port.membase + UFCR);
+ reg = readl(sport->port.membase + UFCR);
+ if (!(reg & UFCR_DCEDTE))
+ writel(reg | UFCR_DCEDTE, sport->port.membase + UFCR);
/*
* Disable UCR3_RI and UCR3_DCD irqs. They are also not
@@ -2195,7 +2197,15 @@ static int serial_imx_probe(struct platform_device *pdev)
sport->port.membase + UCR3);
} else {
- writel(0, sport->port.membase + UFCR);
+ unsigned long ucr3 = UCR3_DSR;
+
+ reg = readl(sport->port.membase + UFCR);
+ if (reg & UFCR_DCEDTE)
+ writel(reg & ~UFCR_DCEDTE, sport->port.membase + UFCR);
+
+ if (!is_imx1_uart(sport))
+ ucr3 |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP;
+ writel(ucr3, sport->port.membase + UCR3);
}
clk_disable_unprepare(sport->clk_ipg);
--
2.11.0
--
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