From 81e4de4ba298d73fce72c70eddeb86b151640c27 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Wed, 9 Apr 2025 14:22:12 -0500 Subject: [PATCH] serial: 8250_of: add support for an optional bus clock 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 Link: https://lore.kernel.org/r/20250409192213.1130181-3-elder@riscstar.com Signed-off-by: Greg Kroah-Hartman --- 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; + + bus_clk = devm_clk_get_optional_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; -- 2.51.0