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 > >> > > > >> > > 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 > >> > > Signed-off-by: Hal Feng > > > >> > > + 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@starfivetech.com/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? > >> > > >> > > + > >> > > + 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 ;)