Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH 1/1] cpufreq: imx6q: imx6ull: use PLL1 for frequency higher than 528MHz | Date | Wed, 02 Aug 2017 01:25:14 +0200 |
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On Friday, July 28, 2017 10:36:33 AM Sébastien Szymanski wrote: > Setting the frequency higher than 528Mhz actually sets the ARM > clock to 528MHz. That's because PLL2 is used as the root clock when the > frequency is higher than 396MHz. > > cpupower frequency-set -f 792000 > > arm_clk_root on the CCM_CLKO2 signal is 528MHz instead of 792MHz. > > [ 61.606383] cpu cpu0: 396 MHz, 1025 mV --> 792 MHz, 1225 mV > > pll2 1 1 528000000 0 0 > pll2_bypass 1 1 528000000 0 0 > pll2_bus 3 3 528000000 0 0 > ca7_secondary_sel 1 1 528000000 0 0 > step 1 1 528000000 0 0 > pll1_sw 1 1 528000000 0 0 > arm 1 1 528000000 0 0 > > Fixes this by using the PLL1 as the root clock when the frequency is > higher than 528MHz. > > cpupower frequency-set -f 792000 > > arm_clk_root on the CCM_CLKO2 signal is now 792MHz as expected. > > [ 69.717987] cpu cpu0: 198 MHz, 950 mV --> 792 MHz, 1225 mV > > pll1 1 1 792000000 0 0 > pll1_bypass 1 1 792000000 0 0 > pll1_sys 1 1 792000000 0 0 > pll1_sw 1 1 792000000 0 0 > arm 1 1 792000000 0 0 > > Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com> > --- > drivers/cpufreq/imx6q-cpufreq.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c > index b6edd3c..e5fba50 100644 > --- a/drivers/cpufreq/imx6q-cpufreq.c > +++ b/drivers/cpufreq/imx6q-cpufreq.c > @@ -18,6 +18,7 @@ > > #define PU_SOC_VOLTAGE_NORMAL 1250000 > #define PU_SOC_VOLTAGE_HIGH 1275000 > +#define FREQ_528_MHZ 528000000 > #define FREQ_1P2_GHZ 1200000000 > > static struct regulator *arm_reg; > @@ -110,14 +111,20 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index) > * voltage of 528MHz, so lower the CPU frequency to one > * half before changing CPU frequency. > */ > - clk_set_rate(arm_clk, (old_freq >> 1) * 1000); > - clk_set_parent(pll1_sw_clk, pll1_sys_clk); > + if ((old_freq * 1000) <= FREQ_528_MHZ) { > + clk_set_rate(arm_clk, (old_freq >> 1) * 1000); > + clk_set_parent(pll1_sw_clk, pll1_sys_clk); > + } > if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) > clk_set_parent(secondary_sel_clk, pll2_bus_clk); > else > clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk); > clk_set_parent(step_clk, secondary_sel_clk); > clk_set_parent(pll1_sw_clk, step_clk); > + if (freq_hz > FREQ_528_MHZ) { > + clk_set_rate(pll1_sys_clk, freq_hz); > + clk_set_parent(pll1_sw_clk, pll1_sys_clk); > + } > } else { > clk_set_parent(step_clk, pll2_pfd2_396m_clk); > clk_set_parent(pll1_sw_clk, step_clk); >
Any comments anyone? Good, bad, ugly?
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