Re: [PATCH v2 3/3] media: camss: Link CAMSS power domain

From: Bryan O'Donoghue
Date: Fri May 26 2023 - 16:50:08 EST


On 26/05/2023 19:07, Yassine Oudjana wrote:
From: Yassine Oudjana <y.oudjana@xxxxxxxxxxxxxx>

The CAMSS power domain was previously enabled implicitly when the VFE
power domains were enabled.
Commit 46cc03175498 ("media: camss: Split power domain management")
delayed enabling VFE power domains which in turn delayed enabling the
CAMSS power domain. This made CSIPHY fail to enable camss_top_ahb_clk
which requires the CAMSS power domain to be on:

[ 199.097810] ------------[ cut here ]------------
[ 199.097893] camss_top_ahb_clk status stuck at 'off'
[ 199.097913] WARNING: CPU: 3 PID: 728 at drivers/clk/qcom/clk-branch.c:91 clk_branch_wait+0x140/0x160
...
[ 199.100064] clk_branch_wait+0x140/0x160
[ 199.100112] clk_branch2_enable+0x30/0x40
[ 199.100159] clk_core_enable+0x6c/0xb0
[ 199.100211] clk_enable+0x2c/0x50
[ 199.100257] camss_enable_clocks+0x94/0xe0 [qcom_camss]
[ 199.100342] csiphy_set_power+0x154/0x2a0 [qcom_camss]
...
[ 199.101594] ---[ end trace 0000000000000000 ]---

Link the CAMSS power domain in camss_configure_pd to make sure it gets
enabled before CSIPHY tries to enable clocks.

Fixes: 02afa816dbbf ("media: camss: Add basic runtime PM support")
Signed-off-by: Yassine Oudjana <y.oudjana@xxxxxxxxxxxxxx>
---
drivers/media/platform/qcom/camss/camss.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
index 1ef26aea3eae..9aea8220d923 100644
--- a/drivers/media/platform/qcom/camss/camss.c
+++ b/drivers/media/platform/qcom/camss/camss.c
@@ -1453,6 +1453,7 @@ static const struct media_device_ops camss_media_ops = {
static int camss_configure_pd(struct camss *camss)
{
struct device *dev = camss->dev;
+ int camss_pd_index;
int i;
int ret;
@@ -1496,7 +1497,13 @@ static int camss_configure_pd(struct camss *camss)
}
}
- if (i > camss->vfe_num) {
+ /* Link CAMSS power domain if available */
+ camss_pd_index = device_property_match_string(camss->dev, "power-domain-names", "camss");
+ if (camss_pd_index >= 0)
+ device_link_add(camss->dev, camss->genpd[camss_pd_index], DL_FLAG_STATELESS |
+ DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE);
+
+ if (i > camss->vfe_num && i != camss_pd_index) {
camss->genpd_link[i - 1] = device_link_add(camss->dev, camss->genpd[i - 1],
DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
DL_FLAG_RPM_ACTIVE);

Konrad pointed this out.

Are you 100% sure you want to do this. We already have a way to count the # of power-domains in camss_configure_pd().

Your series is now adding a dependency on power-domain-names.

Is there a good reason to add that dependency ? If not, then lets just take the code from camss_configure_pd() and make it so that it can be used/reused here.

---
bod