10.12.2019 19:53, Sowjanya Komatineni пишет: > > On 12/9/19 3:03 PM, Sowjanya Komatineni wrote: >> >> On 12/9/19 12:46 PM, Sowjanya Komatineni wrote: >>> >>> On 12/9/19 12:12 PM, Dmitry Osipenko wrote: >>>> 08.12.2019 00:36, Sowjanya Komatineni пишет: >>>>> On 12/7/19 11:59 AM, Sowjanya Komatineni wrote: >>>>>> On 12/7/19 8:00 AM, Dmitry Osipenko wrote: >>>>>>> 07.12.2019 18:53, Dmitry Osipenko пишет: >>>>>>>> 07.12.2019 18:47, Dmitry Osipenko пишет: >>>>>>>>> 07.12.2019 17:28, Dmitry Osipenko пишет: >>>>>>>>>> 06.12.2019 05:48, Sowjanya Komatineni пишет: >>>>>>>>>>> Tegra210 and prior Tegra PMC has clk_out_1, clk_out_2, clk_out_3 >>>>>>>>>>> with >>>>>>>>>>> mux and gate for each of these clocks. >>>>>>>>>>> >>>>>>>>>>> Currently these PMC clocks are registered by Tegra clock driver >>>>>>>>>>> using >>>>>>>>>>> clk_register_mux and clk_register_gate by passing PMC base >>>>>>>>>>> address >>>>>>>>>>> and register offsets and PMC programming for these clocks >>>>>>>>>>> happens >>>>>>>>>>> through direct PMC access by the clock driver. >>>>>>>>>>> >>>>>>>>>>> With this, when PMC is in secure mode any direct PMC access >>>>>>>>>>> from the >>>>>>>>>>> non-secure world does not go through and these clocks will >>>>>>>>>>> not be >>>>>>>>>>> functional. >>>>>>>>>>> >>>>>>>>>>> This patch adds these clocks registration with PMC as a clock >>>>>>>>>>> provider >>>>>>>>>>> for these clocks. clk_ops callback implementations for these >>>>>>>>>>> clocks >>>>>>>>>>> uses tegra_pmc_readl and tegra_pmc_writel which supports PMC >>>>>>>>>>> programming >>>>>>>>>>> in secure mode and non-secure mode. >>>>>>>>>>> >>>>>>>>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx> >>>>>>>>>>> --- >>>>>>>>> [snip] >>>>>>>>> >>>>>>>>>>> + >>>>>>>>>>> +static const struct clk_ops pmc_clk_gate_ops = { >>>>>>>>>>> + .is_enabled = pmc_clk_is_enabled, >>>>>>>>>>> + .enable = pmc_clk_enable, >>>>>>>>>>> + .disable = pmc_clk_disable, >>>>>>>>>>> +}; >>>>>>>>>> What's the benefit of separating GATE from the MUX? >>>>>>>>>> >>>>>>>>>> I think it could be a single clock. >>>>>>>>> According to TRM: >>>>>>>>> >>>>>>>>> 1. GATE and MUX are separate entities. >>>>>>>>> >>>>>>>>> 2. GATE is the parent of MUX (see PMC's CLK_OUT paths diagram >>>>>>>>> in TRM). >>>>>>>>> >>>>>>>>> 3. PMC doesn't gate EXTPERIPH clock but could "force-enable" it, >>>>>>>>> correct? >>>>> Was following existing clk-tegra-pmc as I am not sure of reason for >>>>> having these clocks registered as separate mux and gate clocks. >>>>> >>>>> Yes, PMC clocks can be registered as single clock and can use clk_ops >>>>> for set/get parent and enable/disable. >>>>> >>>>> enable/disable of PMC clocks is for force-enable to force the clock to >>>>> run regardless of ACCEPT_REQ or INVERT_REQ. >>>>> >>>>>>>> 4. clk_m_div2/4 are internal PMC OSC dividers and thus these clocks >>>>>>>> should belong to PMC. >>>>>>> Also, it should be "osc" and not "clk_m". >>>>>> I followed the same parents as it were in existing clk-tegra-pmc >>>>>> driver. >>>>>> >>>>>> Yeah they are wrong and they should be from osc and not clk_m. >>>>>> >>>>>> Will fix in next version. >>>>>> >> Reg clk_m_div2/3, they are dividers at OSC pad and not really internal >> to PMC block. >> >> current clock driver creates clk_m_div clocks which should actually be >> osc_div2/osc_div4 clocks with osc as parent. >> >> There are no clk_m_div2 and clk_m_div4 from clk_m >> >> Will fix this in next version. >> >>>> Could you please describe the full EXTPERIPH clock topology and how the >>>> pinmux configuration is related to it all? >>>> >>>> What is internal to the Tegra chip and what are the external outputs? >>>> >>>> Is it possible to bypass PMC on T30+ for the EXTPERIPH clocks? >>> >>> PMC CLK1/2/3 possible sources are OSC_DIV1, OSC_DIV2, OSC_DIV4, >>> EXTPERIPH from CAR. >>> >>> OSC_DIV1/2/4 are with internal dividers at the OSC Pads >>> >>> EXTPERIPH is from CAR and it has reset and enable controls along with >>> clock source selections to choose one of the PLLA_OUT0, CLK_S, >>> PLLP_OUT0, CLK_M, PLLE_OUT0 >>> >>> So, PMC CLK1/2/4 possible parents are OSC_DIV1, OSC_DIV2, OSC_DIV4, >>> EXTERN. >>> >>> >>> CLK1/2/3 also has Pinmux to route EXTPERIPH output on to these pins. >>> >>> >>> When EXTERN output clock is selected for these PMC clocks thru >>> CLKx_SRC_SEL, output clock is from driver by EXTPERIPH from CAR via >>> Pinmux logic or driven as per CLKx_SRC_SEL bypassing pinmux based on >>> CLKx_ACCEPT_REQ bit. >>> >>> >>> PMC Clock control register has bit CLKx_ACCEPT_REQ >>> When CLKx_ACCEPT_REQ = 0, output clock driver is from by EXTPERIPH >>> through the pinmux >>> When CLKx_ACCEPT_REQ = 1, output clock is based on CLKx_SRC_SEL bits >>> (OSC_DIV1/2/4 and EXTPERIPH clock bypassing the pinmux) >>> >>> FORCE_EN bit in PMC CLock control register forces the clock to run >>> regardless of this. > > PMC clock gate is based on the state of CLKx_ACCEPT_REQ and FORCE_EN > like explained above. > > CLKx_ACCEPT_REQ is 0 default and FORCE_EN acts as gate to enable/disable > EXTPERIPH clock output to PMC CLK_OUT_1/2/3. [and to enable OSC as well] > So I believe we need to register as MUX and Gate rather than as a single > clock. Please confirm. 1. The force-enabling is applied to both OSC and EXTERN sources of PMC_CLK_OUT_x by PMC at once. 2. Both of PMC's force-enabling and OSC/EXTERN selection is internal to PMC. Should be better to define it as a single "pmc_clk_out_x". I don't see any good reasons for differentiating PMC's Gate from the MUX, it's a single hardware unit from a point of view of the rest of the system. Peter, do you have any objections? _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel