Re: [PATCH v9 20/22] soc/tegra: pmc: Configure deep sleep control settings

From: Sowjanya Komatineni
Date: Mon Aug 19 2019 - 14:20:26 EST

On 8/19/19 9:48 AM, Dmitry Osipenko wrote:
16.08.2019 22:42, Sowjanya Komatineni ÐÐÑÐÑ:
Tegra210 and prior Tegra chips have deep sleep entry and wakeup related
timings which are platform specific that should be configured before
entering into deep sleep.

Below are the timing specific configurations for deep sleep entry and
- Core rail power-on stabilization timer
- OSC clock stabilization timer after SOC rail power is stabilized.
- Core power off time is the minimum wake delay to keep the system
in deep sleep state irrespective of any quick wake event.

These values depends on the discharge time of regulators and turn OFF
time of the PMIC to allow the complete system to finish entering into
deep sleep state.

These values vary based on the platform design and are specified
through the device tree.

This patch has implementation to configure these timings which are must
to have for proper deep sleep and wakeup operations.

Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
drivers/soc/tegra/pmc.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
index 53ed70773872..710969043668 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -88,6 +88,8 @@
#define PMC_PWR_DET_VALUE 0xe4
@@ -2277,7 +2279,7 @@ static const struct tegra_pmc_regs tegra20_pmc_regs = {
static void tegra20_pmc_init(struct tegra_pmc *pmc)
- u32 value;
+ u32 value, osc, pmu, off;
/* Always enable CPU power request */
value = tegra_pmc_readl(pmc, PMC_CNTRL);
@@ -2303,6 +2305,16 @@ static void tegra20_pmc_init(struct tegra_pmc *pmc)
value = tegra_pmc_readl(pmc, PMC_CNTRL);
tegra_pmc_writel(pmc, value, PMC_CNTRL);
+ /* program core timings which are applicable only for suspend state */
+ if (pmc->suspend_mode != TEGRA_SUSPEND_NONE) {
+ osc = DIV_ROUND_UP(pmc->core_osc_time * 8192, 1000000);
+ pmu = DIV_ROUND_UP(pmc->core_pmu_time * 32768, 1000000);
+ off = DIV_ROUND_UP(pmc->core_off_time * 32768, 1000000);
+ tegra_pmc_writel(pmc, ((osc << 8) & 0xff00) | (pmu & 0xff),
+ tegra_pmc_writel(pmc, off, PMC_COREPWROFF_TIMER);
+ }
static void tegra20_pmc_setup_irq_polarity(struct tegra_pmc *pmc,

In the previous version of this patch there were checks for zero values
of the timers with intention to skip programming of the timers if value
is zero. I'm a bit puzzled by the new version, given that SUSPEND_NONE
means that suspending isn't available at all and thus PMC timers won't
be utilized, hence it shouldn't matter what values are programmed for
the counters, isn't it?

Yes, as I see in documentation we already specify all these timings are required properties when suspend mode is used, I updated in this version to program core timings only when suspend mode is enabled.