Hi,
Le mar., avril 12 2022 at 13:27:50 +0100, Aidan MacDonald
<aidanmacdonald.0x0@xxxxxxxxx> a écrit :
The TCU clock gate on X1000 wasn't requested by the driver and could
be gated automatically later on in boot, which prevents timers from
running and breaks PWM.
Add a workaround to support old device trees that don't specify the
"tcu" clock gate. In this case the kernel will print a warning and
attempt to continue without the clock, which is wrong, but it could
work if "clk_ignore_unused" is in the kernel arguments.
Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@xxxxxxxxx>
Reviewed-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
Cheers,
-Paul
---
drivers/clk/ingenic/tcu.c | 35 +++++++++++++++++++++++++----------
1 file changed, 25 insertions(+), 10 deletions(-)
diff --git a/drivers/clk/ingenic/tcu.c b/drivers/clk/ingenic/tcu.c
index 77acfbeb4830..201bf6e6b6e0 100644
--- a/drivers/clk/ingenic/tcu.c
+++ b/drivers/clk/ingenic/tcu.c
@@ -31,6 +31,7 @@ struct ingenic_soc_info {
unsigned int num_channels;
bool has_ost;
bool has_tcu_clk;
+ bool allow_missing_tcu_clk;
};
struct ingenic_tcu_clk_info {
@@ -320,7 +321,8 @@ static const struct ingenic_soc_info
jz4770_soc_info = {
static const struct ingenic_soc_info x1000_soc_info = {
.num_channels = 8,
.has_ost = false, /* X1000 has OST, but it not belong TCU */
- .has_tcu_clk = false,
+ .has_tcu_clk = true,
+ .allow_missing_tcu_clk = true,
};
static const struct of_device_id __maybe_unused
ingenic_tcu_of_match[] __initconst = {
@@ -355,14 +357,27 @@ static int __init ingenic_tcu_probe(struct
device_node *np)
tcu->clk = of_clk_get_by_name(np, "tcu");
if (IS_ERR(tcu->clk)) {
ret = PTR_ERR(tcu->clk);
- pr_crit("Cannot get TCU clock\n");
- goto err_free_tcu;
- }
- ret = clk_prepare_enable(tcu->clk);
- if (ret) {
- pr_crit("Unable to enable TCU clock\n");
- goto err_put_clk;
+ /*
+ * Old device trees for some SoCs did not include the
+ * TCU clock because this driver (incorrectly) didn't
+ * use it. In this case we complain loudly and attempt
+ * to continue without the clock, which might work if
+ * booting with workarounds like "clk_ignore_unused".
+ */
+ if (tcu->soc_info->allow_missing_tcu_clk && ret == -EINVAL) {
+ pr_warn("TCU clock missing from device tree, please update your
device tree\n");
+ tcu->clk = NULL;
+ } else {
+ pr_crit("Cannot get TCU clock from device tree\n");
+ goto err_free_tcu;
+ }
+ } else {
+ ret = clk_prepare_enable(tcu->clk);
+ if (ret) {
+ pr_crit("Unable to enable TCU clock\n");
+ goto err_put_clk;
+ }
}
}
@@ -432,10 +447,10 @@ static int __init ingenic_tcu_probe(struct
device_node *np)
clk_hw_unregister(tcu->clocks->hws[i]);
kfree(tcu->clocks);
err_clk_disable:
- if (tcu->soc_info->has_tcu_clk)
+ if (tcu->clk)
clk_disable_unprepare(tcu->clk);
err_put_clk:
- if (tcu->soc_info->has_tcu_clk)
+ if (tcu->clk)
clk_put(tcu->clk);
err_free_tcu:
kfree(tcu);
--
2.35.1
