On Thu, 16 Feb 2023 18:20:34 +0000, Conor Dooley wrote: > Hey Hal! > > On Thu, Feb 16, 2023 at 10:42:20PM +0800, Hal Feng wrote: >> On Tue, 27 Dec 2022 20:15:20 +0000, Conor Dooley wrote: >> > On Mon, Dec 26, 2022 at 12:26:32AM +0800, Hal Feng wrote: >> >> On Tue, 20 Dec 2022 23:14:39 +0000, Conor Dooley wrote: >> >> > On Tue, Dec 20, 2022 at 08:50:50AM +0800, Hal Feng wrote: >> >> > > From: Emil Renner Berthing <kernel@xxxxxxxx> >> >> > > >> >> > > Add bindings for the system clock and reset generator (SYSCRG) on the >> >> > > JH7110 RISC-V SoC by StarFive Ltd. >> >> > > >> >> > > Signed-off-by: Emil Renner Berthing <kernel@xxxxxxxx> >> >> > > Signed-off-by: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx> >> > >> >> > > + clocks: >> >> > > + items: >> >> > > + - description: Main Oscillator (24 MHz) >> >> > > + - description: GMAC1 RMII reference >> >> > > + - description: GMAC1 RGMII RX >> >> > > + - description: External I2S TX bit clock >> >> > > + - description: External I2S TX left/right channel clock >> >> > > + - description: External I2S RX bit clock >> >> > > + - description: External I2S RX left/right channel clock >> >> > > + - description: External TDM clock >> >> > > + - description: External audio master clock >> >> > >> >> > So, from peeking at the clock driver & the dt - it looks like a bunch of >> >> > these are not actually required? >> >> >> >> These clocks are used as root clocks or optional parent clocks in clock tree. >> >> Some of them are optional, but they are required if we want to describe the >> >> complete clock tree of JH7110 SoC. >> > >> > Perhaps I have a misunderstand of what required means. To me, required >> > means "you must provide this clock for the SoC to operate in all >> > configurations". >> > Optional therefore would be for things that are needed only for some >> > configurations and may be omitted if not required. >> > >> > From your comment below, boards with a JH7110 may choose not to populate >> > both external clock inputs to a mux. In that case, "dummy" clocks should >> > not have to be provided in the DT of such boards to satisfy this binding >> > which seems wrong to me.. >> >> Please see the picture of these external clocks in clock tree. >> >> # mount -t debugfs none /mnt >> # cat /mnt/clk/clk_summary >> enable prepare protect duty hardware >> clock count count count rate accuracy phase cycle enable >> ------------------------------------------------------------------------------------------------------- >> *mclk_ext* 0 0 0 12288000 0 0 50000 Y >> *tdm_ext* 0 0 0 49152000 0 0 50000 Y >> *i2srx_lrck_ext* 0 0 0 192000 0 0 50000 Y >> *i2srx_bclk_ext* 0 0 0 12288000 0 0 50000 Y >> *i2stx_lrck_ext* 0 0 0 192000 0 0 50000 Y >> *i2stx_bclk_ext* 0 0 0 12288000 0 0 50000 Y >> *gmac1_rgmii_rxin* 0 0 0 125000000 0 0 50000 Y >> gmac1_rx 0 0 0 125000000 0 0 50000 Y >> gmac1_rx_inv 0 0 0 125000000 0 180 50000 Y >> *gmac1_rmii_refin* 0 0 0 50000000 0 0 50000 Y >> gmac1_rmii_rtx 0 0 0 50000000 0 0 50000 Y >> gmac1_tx 0 0 0 50000000 0 0 50000 N >> gmac1_tx_inv 0 0 0 50000000 0 180 50000 Y >> *osc* 4 4 0 24000000 0 0 50000 Y >> apb_func 0 0 0 24000000 0 0 50000 Y >> ... >> >> The clock "gmac1_rgmii_rxin" and the clock "gmac1_rmii_refin" are >> actually used as the parent of other clocks. > >> The "dummy" clocks >> you said are all internal clocks. > > No, what I meant by "dummy" clocks is that if you make clocks "required" > in the binding that are not needed by the hardware for operation a > customer of yours might have to add "dummy" clocks to their devicetree > to pass dtbs_check. > >> For the audio related clocks (mclk_ext/tdm_ext/i2srx_lrck_ext/ >> i2srx_bclk_ext/i2stx_lrck_ext/i2stx_bclk_ext), they will be used >> as the parent clocks in audio related drivers. Note that some >> clocks need to select different clocks as parent according to >> requirement. >> So all these external clocks are required. >> >> > >> > It would seem to me that you need to set minItems < maxItems here to >> > account for that & you do in fact need clock-names. >> > >> >> >> >> > I'd have ploughed through this, but having read Krzysztof's comments on >> >> > the DTS I'm not sure that this binding is correct. >> >> > https://lore.kernel.org/linux-riscv/20221220011247.35560-1-hal.feng@xxxxxxxxxxxxxxxx/T/#mdf67621a2344dce801aa8015d4963593a2c28bcc >> >> > >> >> > I *think* the DT is correct - the fixed clocks are all inputs from clock >> >> > sources on the board and as such they are empty in soc.dtsi and are >> >> > populated in board.dts? >> >> >> >> Yes, the fixed clocks are all clock sources on the board and input to the SoC. >> >> >> >> > >> >> > However, are they all actually required? In the driver I see: >> >> > JH71X0__MUX(JH7110_SYSCLK_GMAC1_RX, "gmac1_rx", 2, >> >> > JH7110_SYSCLK_GMAC1_RGMII_RXIN, >> >> > JH7110_SYSCLK_GMAC1_RMII_RTX), >> >> > That macro is: >> >> > #define JH71X0__MUX(_idx, _name, _nparents, ...) [_idx] = { \ >> >> > .name = _name, \ >> >> > .flags = 0, \ >> >> > .max = ((_nparents) - 1) << JH71X0_CLK_MUX_SHIFT, \ >> >> > .parents = { __VA_ARGS__ }, \ >> >> > } > >> >> > AFAICT, RMII reference feeds RMII_RTX & RGMII RX *is* RGMII_RXIN? >> >> > Does that mean you need to populate only one of GMAC1 RMII reference >> >> > and GMAC1 RMGII RX and the other is optional? > >> >> Yes, actually only one of them is chosen as the root clock >> >> source of the clock "gmac1_rx". > | *gmac1_rgmii_rxin* > | gmac1_rx > | gmac1_rx_inv > | *gmac1_rmii_refin* > | gmac1_rmii_rtx > | gmac1_tx > | gmac1_tx_inv > | > | description: GMAC1 RMII reference > | description: GMAC1 RGMII RX > > > So you're telling me that you can either: > - Provide GMAC1 RMII reference and GMAC1 RGMII RX & then use different > clocks for gmac1_rx and gmac1_tx > - Provide only GMAC1 RMII reference & use it for both gmac1_tx *and* > gmac1_rx > > Is that correct? Yes, it is. Best regards, Hal > >> >> > >> >> > > + >> >> > > + clock-names: >> >> > > + items: >> >> > > + - const: osc >> >> > > + - const: gmac1_rmii_refin >> >> > > + - const: gmac1_rgmii_rxin >> >> > > + - const: i2stx_bclk_ext >> >> > > + - const: i2stx_lrck_ext >> >> > > + - const: i2srx_bclk_ext >> >> > > + - const: i2srx_lrck_ext >> >> > > + - const: tdm_ext >> >> > > + - const: mclk_ext >> >> > >> >> > If all clocks are in fact required though, isn't this kinda pointless to >> >> > have since we already know that the order is fixed from the "clocks" >> >> > property? >> >> > Krzk/Rob? >> >> >> >> The clock-names are used to easily identify these clocks in the clock driver. >> > >> > *IF* all clocks were in fact required, which they aren't, you could rely >> > on the order alone in the driver as it is enforced by the binding. >> >> OK, I'll remove "clock-names" property in the bindings and device tree. >> Instead, will use index to get these clocks in drivers. > > Hang on until you answer my question above before deleting this from the > dt-binding & driver ;) >
