From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
I noticed that uartclk never gets updated as it is today.
This compile tested patch makes sure uartclk is in sync with
whatever clock is selected during sci_set_termios(). Exposing
the actual value to user space seems like a good plan to me.
Another semi-related issue:
The ->termios() callback in the SCIF driver seems to enable clocks using
runtine pm in sci_port_enable() followed by register accesses and
a before returnng sci_port_enable() disables clocks as well.
The ->pm() callback will enable the port again later on however
on SoCs where the SCIF is in a power domain it looks like the
register contents might get lost due to power down between ->termios()
and ->pm()?
Perhaps the power domain use case is known to be busted?
Not-Yet-Signed-off-by: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
---
drivers/tty/serial/sh-sci.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- 0001/drivers/tty/serial/sh-sci.c
+++ work/drivers/tty/serial/sh-sci.c 2019-08-20 20:32:17.680030451 +0900
@@ -129,6 +129,7 @@ struct sci_port {
/* Clocks */
struct clk *clks[SCI_NUM_CLKS];
unsigned long clk_rates[SCI_NUM_CLKS];
+ int sel_clk;
int irqs[SCIx_NR_IRQS];
char *irqstr[SCIx_NR_IRQS];
@@ -542,7 +543,11 @@ static void sci_port_enable(struct sci_p
clk_prepare_enable(sci_port->clks[i]);
sci_port->clk_rates[i] = clk_get_rate(sci_port->clks[i]);
}
- sci_port->port.uartclk = sci_port->clk_rates[SCI_FCK];
+
+ if (sci_port->sel_clk >= 0)
+ sci_port->port.uartclk = sci_port->clk_rates[sci_port->sel_clk];
+ else
+ sci_port->port.uartclk = sci_port->clk_rates[SCI_FCK];
}
static void sci_port_disable(struct sci_port *sci_port)
@@ -2472,6 +2477,7 @@ done:
dev_dbg(port->dev, "Using clk %pC for %u%+d bps\n",
s->clks[best_clk], baud, min_err);
+ s->sel_clk = best_clk;
sci_port_enable(s);
/*
@@ -2785,6 +2791,8 @@ static int sci_init_clocks(struct sci_po
struct clk *clk;
unsigned int i;
+ sci_port->sel_clk = -1; /* invalid */
+
if (sci_port->cfg->type == PORT_HSCIF)
clk_names[SCI_SCK] = "hsck";
