[PATCH v2 15/21] serial_lpuart: add clock enable if CONFIG_CLK is defined

Giulio Benetti
2020-01-10T14:47:05Z

This driver assumes that lpuart clock is already enabled before probing
but using DM only lpuart won't be automatically enabled so add
clk_enable() when probing if CONFIG_CLK is defined. If clock is not
found, because DM is not used, let's emit a warning and proceed, because
serial clock could also be already enabled by non DM code. If clock is
found but cna't be enabled then return with error.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
---
V1->V2:
* moved error as warning if clk not found
---
drivers/serial/serial_lpuart.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/serial/serial_lpuart.c b/drivers/serial/serial_lpuart.c
index 4b0a964d1b..b2ec56172e 100644
--- a/drivers/serial/serial_lpuart.c
+++ b/drivers/serial/serial_lpuart.c
@@ -483,6 +483,22 @@ static int lpuart_serial_pending(struct udevice *dev, bool input)

static int lpuart_serial_probe(struct udevice *dev)
{
+#if CONFIG_IS_ENABLED(CLK)
+ struct clk per_clk;
+ int ret;
+
+ ret = clk_get_by_name(dev, "per", &per_clk);
+ if (!ret) {
+ ret = clk_enable(&per_clk);
+ if (ret) {
+ dev_err(dev, "Failed to get per clk: %d\n", ret);
+ return ret;
+ }
+ } else {
+ dev_warn(dev, "Failed to get per clk: %d\n", ret);
+ }
+#endif
+
if (is_lpuart32(dev))
return _lpuart32_serial_init(dev);
else
--
2.20.1