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net: pcs: xpcs-plat: fix runtime PM initialization

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The driver calls pm_runtime_set_active() before runtime PM is enabled and
before the CSR clock is prepared and enabled. If the device is later
suspended (e.g. during unbind), the runtime suspend callback tries to
disable a clock that was never enabled, producing:

    clk_csr already disabled
    clk_csr already unprepared

Set the initial runtime PM status to suspended instead, and register a
devm action that force-suspends the device on teardown. Without that
action the CSR clock would stay enabled if the driver is removed while
runtime-active, since nothing triggers a runtime suspend on unbind.
pm_runtime_force_suspend() is not checked because the runtime suspend
callback cannot fail.

The clock is enabled on the first runtime resume (e.g. during MDIO
access).

No upstream platform currently enables this driver with a real CSR clock
dependency, so the issue is not reachable in mainline today. It was
found while using this driver as a reference for the Rockchip XPCS glue
driver.

Signed-off-by: Coia Prant <coiaprant@gmail.com>
Link: https://patch.msgid.link/20261023075214.1793922-3-coiaprant@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Coia Prant 2026-10-23 15:52:12 +08:00 committed by Jakub Kicinski
parent 8146be0490
commit 49d8bbc212
1 changed files with 13 additions and 3 deletions
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16
drivers/net/pcs/pcs-xpcs-plat.c
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@ -275,6 +275,14 @@ static int xpcs_plat_init_res(struct dw_xpcs_plat *pxpcs)
return 0;
}
static void xpcs_plat_exit_clk(void *data)
{
struct dw_xpcs_plat *pxpcs = data;
struct device *dev = &pxpcs->pdev->dev;
pm_runtime_force_suspend(dev);
}
static int xpcs_plat_init_clk(struct dw_xpcs_plat *pxpcs)
{
struct device *dev = &pxpcs->pdev->dev;
@ -285,10 +293,12 @@ 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 = devm_pm_runtime_enable(dev);
pm_runtime_set_suspended(dev);
pm_runtime_enable(dev);
ret = devm_add_action_or_reset(dev, xpcs_plat_exit_clk, pxpcs);
if (ret) {
dev_err(dev, "Failed to enable runtime-PM\n");
dev_err(dev, "Failed to register devm for xpcs_plat_exit_clk: %d\n", ret);
return ret;
}