Hi Stephen,
On 5/24/25 00:58, Stephen Boyd wrote:
Enable the serial engine clk in probe so that this driver can work on
platforms that don't already initialize the clk for this device before
this driver runs. This fixes a problem I see on Coreboot platforms like
Trogdor where the UART hardware isn't enabled by coreboot unless the
serial console build is used.
Signed-off-by: Stephen Boyd <swb...@chromium.org>
---
drivers/serial/serial_msm_geni.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/drivers/serial/serial_msm_geni.c b/drivers/serial/serial_msm_geni.c
index cb6c09fdd09e..620cb9a59343 100644
--- a/drivers/serial/serial_msm_geni.c
+++ b/drivers/serial/serial_msm_geni.c
@@ -131,6 +131,7 @@ struct msm_serial_data {
phys_addr_t base;
u32 baud;
u32 oversampling;
+ struct clk *se;
};
unsigned long root_freq[] = {7372800, 14745600, 19200000, 29491200,
@@ -181,19 +182,6 @@ static int get_clk_div_rate(u32 baud, u64 sampling_rate,
u32 *clk_div)
return ser_clk;
}
-static int geni_serial_set_clock_rate(struct udevice *dev, u64 rate)
-{
- struct clk *clk;
- int ret;
-
- clk = devm_clk_get(dev, NULL);
- if (IS_ERR(clk))
- return PTR_ERR(clk);
-
- ret = clk_set_rate(clk, rate);
- return ret;
-}
-
/**
* geni_se_get_tx_fifo_depth() - Get the TX fifo depth of the serial engine
* @base: Pointer to the concerned serial engine.
@@ -252,7 +240,7 @@ static int msm_serial_setbrg(struct udevice *dev, int baud)
priv->baud = baud;
clk_rate = get_clk_div_rate(baud, priv->oversampling, &clk_div);
- ret = geni_serial_set_clock_rate(dev, clk_rate);
+ ret = clk_set_rate(priv->se, clk_rate);
if (ret < 0) {
pr_err("%s: Couldn't set clock rate: %d\n", __func__, ret);
return ret;
@@ -561,6 +549,16 @@ static int msm_serial_probe(struct udevice *dev)
{
struct msm_serial_data *priv = dev_get_priv(dev);
int ret;
+ struct clk *clk;
+
+ clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+ priv->se = clk;
+
+ ret = clk_enable(clk);
+ if (ret)
+ return ret;
There's a subtle change in behaviour here, since we'll now fail probe if
the clock isn't found. I think it would be best to treat this clock
being missing as non-fatal since it can make bringup a little easier (no
need to stub the clock).
Kind regards,>
ret = geni_set_oversampling(dev);
if (ret < 0)
--
Casey (she/they)
