Messages in this thread |  | | Date | Wed, 9 Apr 2025 21:43:45 +0000 | | From | Yixun Lan <> | | Subject | Re: [PATCH v2 2/2] serial: 8250_of: add support for an optional bus clock |
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Hi Alex,
On 14:22 Wed 09 Apr , Alex Elder wrote: > The SpacemiT UART requires a bus clock to be enabled, in addition to > it's "normal" core clock. Look up the optional bus clock by name, > and if that's found, look up the core clock using the name "core". > > Supplying a bus clock is optional. If no bus clock is needed, the > the first/only clock is used for the core clock. > > Signed-off-by: Alex Elder <elder@riscstar.com> > --- > v2: Update logic to more check for the optional bus clock first > > drivers/tty/serial/8250/8250_of.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c > index 11c860ea80f60..a90a5462aa72a 100644 > --- a/drivers/tty/serial/8250/8250_of.c > +++ b/drivers/tty/serial/8250/8250_of.c > @@ -123,7 +123,16 @@ static int of_platform_serial_setup(struct platform_device *ofdev, > > /* Get clk rate through clk driver if present */ > if (!port->uartclk) { > - info->clk = devm_clk_get_enabled(dev, NULL); > + struct clk *bus_clk; we also need to handle clk in suspend/resume procedure, so I think you need to put bus_clk inside struct of_serial_info..
> + > + bus_clk = devm_clk_get_optional_enabled(dev, "bus"); for the 'optional', we can interpret it's optional for other vendor UART, but a must required clk for SpacemiT's k1 UART controller
would it better to guard this inside a compatible test or even introduce a flag in compatible data?
if (of_device_is_compatible(pdev->dev.of_node, "spacemit,k1-uart")) { bus_clk = devm_clk_get_enabled(dev, "bus"); .. }
} > + if (IS_ERR(bus_clk)) { > + ret = dev_err_probe(dev, PTR_ERR(bus_clk), "failed to get bus clock\n"); > + goto err_pmruntime; > + } > + > + /* If the bus clock is required, core clock must be named */ > + info->clk = devm_clk_get_enabled(dev, bus_clk ? "core" : NULL); > if (IS_ERR(info->clk)) { > ret = dev_err_probe(dev, PTR_ERR(info->clk), "failed to get clock\n"); > goto err_pmruntime; > -- > 2.45.2 >
-- Yixun Lan (dlan) Gentoo Linux Developer GPG Key ID AABEFD55
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