[PATCH RFC net-next 5/9] net: pcs: xpcs: initialize runtime PM as suspended

[Mohd Ayaan Anwar]

xpcs_plat_init_clk() acquires the optional CSR clock but does not
prepare or enable it. Marking the device runtime-active at that point
makes the PM core assume that the hardware is already powered.

On Nord, once the XPCS CSR clock was described, the first
pm_runtime_resume_and_get() accessed XPCS registers without invoking
runtime_resume() to enable the clock. The matching runtime put then
invoked runtime_suspend() and attempted to disable a clock which was
never enabled, producing an already-disabled clock warning.

Initialize the runtime-PM state as suspended instead. The first
register access now runs the resume callback and enables the CSR clock,
while the subsequent suspend callback performs the matching disable.
Check and propagate the state-transition error as part of probe.

Signed-off-by: Mohd Ayaan Anwar <mohd.anwar at oss.qualcomm.com>
---
 drivers/net/pcs/pcs-xpcs-plat.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
index e013a5253a22651220e62352d03faabc3a3c3658..328c50940d46eb8e7bea06ecd1a20214e3cde61c 100644
--- a/drivers/net/pcs/pcs-xpcs-plat.c
+++ b/drivers/net/pcs/pcs-xpcs-plat.c
@@ -322,7 +322,11 @@ static int xpcs_plat_init_clk(struct dw_xpcs_plat *pxpcs)
 		return dev_err_probe(dev, PTR_ERR(pxpcs->cclk),
 				     "Failed to get CSR clock\n");
 
-	pm_runtime_set_active(dev);
+	ret = pm_runtime_set_suspended(dev);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to set runtime-PM suspended state\n");
+
 	ret = devm_pm_runtime_enable(dev);
 	if (ret) {
 		dev_err(dev, "Failed to enable runtime-PM\n");

-- 
2.34.1