On Thu, Aug 08, 2019 at 04:46:50PM -0700, Sowjanya Komatineni wrote:
> This patch implements DFLL suspend and resume operation.
>
> During system suspend entry, CPU clock will switch CPU to safe
> clock source of PLLP and disables DFLL clock output.
>
> DFLL driver suspend confirms DFLL disable state and errors out on
> being active.
>
> DFLL is re-initialized during the DFLL driver resume as it goes
> through complete reset during suspend entry.
>
> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
> ---
> drivers/clk/tegra/clk-dfll.c | 56 ++++++++++++++++++++++++++++++
> drivers/clk/tegra/clk-dfll.h | 2 ++
> drivers/clk/tegra/clk-tegra124-dfll-fcpu.c | 1 +
> 3 files changed, 59 insertions(+)
>
> diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
> index f8688c2ddf1a..eb298a5d7be9 100644
> --- a/drivers/clk/tegra/clk-dfll.c
> +++ b/drivers/clk/tegra/clk-dfll.c
> @@ -1487,6 +1487,7 @@ static int dfll_init(struct tegra_dfll *td)
> td->last_unrounded_rate = 0;
>
> pm_runtime_enable(td->dev);
> + pm_runtime_irq_safe(td->dev);
> pm_runtime_get_sync(td->dev);
>
> dfll_set_mode(td, DFLL_DISABLED);
> @@ -1513,6 +1514,61 @@ static int dfll_init(struct tegra_dfll *td)
> return ret;
> }
>
> +/**
> + * tegra_dfll_suspend - check DFLL is disabled
> + * @dev: DFLL device *
> + *
> + * DFLL clock should be disabled by the CPUFreq driver. So, make
> + * sure it is disabled and disable all clocks needed by the DFLL.
> + */
> +int tegra_dfll_suspend(struct device *dev)
> +{
> + struct tegra_dfll *td = dev_get_drvdata(dev);
> +
> + if (dfll_is_running(td)) {
> + dev_err(td->dev, "dfll is enabled while shouldn't be\n");
Minor nit: "DFLL" in the error message, just like you have in the
kerneldoc comment above. Perhaps also make the error message a little
more specific. "while shouldn't be" makes the user guess what that
means. Perhaps better to say something like:
"DFLL still enabled while suspending\n"
or perhaps even add a hint as to what could be the culprit:
"DFLL still enabled while suspending, possibly a cpufreq driverbug\n"
The latter is somewhat long and the former is enough because the
kerneldoc comment already explains that cpufreq might be the reason for
this.
With a more specific error message, this is:
Acked-by: Thierry Reding <treding@xxxxxxxxxx>
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