Re: [PATCH v4 3/5] Documentation: devicetree: ufs: Add DT bindings for exynos UFS host controller

[Rob Herring <robh@kernel.org>]

On Fri, Mar 27, 2020 at 10:36:36PM +0530, Alim Akhtar wrote:
> This adds Exynos Universal Flash Storage (UFS) Host Controller DT bindings.

Why the inconsistent subject. 'dt-bindings: ...' please.

> 
> Signed-off-by: Seungwon Jeon <essuuj@gmail.com>
> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
> ---
>  .../devicetree/bindings/ufs/ufs-exynos.txt    | 104 ++++++++++++++++++
>  1 file changed, 104 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/ufs/ufs-exynos.txt

Use DT schema format. Not sure why you'd do that for one and not the 
other...

> 
> diff --git a/Documentation/devicetree/bindings/ufs/ufs-exynos.txt b/Documentation/devicetree/bindings/ufs/ufs-exynos.txt
> new file mode 100644
> index 000000000000..08e2d1497b1b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/ufs/ufs-exynos.txt
> @@ -0,0 +1,104 @@
> +* Exynos Universal Flash Storage (UFS) Host Controller
> +
> +UFSHC nodes are defined to describe on-chip UFS host controllers.
> +Each UFS controller instance should have its own node.
> +
> +Required properties:
> +- compatible        : compatible name, contains "samsung,exynos7-ufs"
> +- interrupts        : <interrupt mapping for UFS host controller IRQ>
> +- reg               : Should contain HCI, vendor specific, UNIPRO and
> +		      UFS protector address space
> +- reg-names	    : "hci", "vs_hci", "unipro", "ufsp";
> +
> +Optional properties:
> +- vdd-hba-supply        : phandle to UFS host controller supply regulator node
> +- vcc-supply            : phandle to VCC supply regulator node
> +- vccq-supply           : phandle to VCCQ supply regulator node
> +- vccq2-supply          : phandle to VCCQ2 supply regulator node
> +- vcc-supply-1p8        : For embedded UFS devices, valid VCC range is 1.7-1.95V
> +                          or 2.7-3.6V. This boolean property when set, specifies
> +			  to use low voltage range of 1.7-1.95V. Note for external
> +			  UFS cards this property is invalid and valid VCC range is
> +			  always 2.7-3.6V.

The supply for vcc-supply should be restricted to the valid range and 
this is not needed.

> +- vcc-max-microamp      : specifies max. load that can be drawn from vcc supply
> +- vccq-max-microamp     : specifies max. load that can be drawn from vccq supply
> +- vccq2-max-microamp    : specifies max. load that can be drawn from vccq2 supply

How is this information useful?

> +- <name>-fixed-regulator : boolean property specifying that <name>-supply is a fixed regulator

No need for this. Look up the phandle and check supply's node if you 
want to know this.

> +
> +- clocks                : List of phandle and clock specifier pairs
> +- clock-names           : List of clock input name strings sorted in the same
> +                          order as the clocks property.
> +			  "core", "sclk_unipro_main", "ref" and ref_parent
> +
> +- freq-table-hz		: Array of <min max> operating frequencies stored in the same
> +			  order as the clocks property. If this property is not
> +			  defined or a value in the array is "0" then it is assumed
> +			  that the frequency is set by the parent clock or a
> +			  fixed rate clock source.
> +- pclk-freq-avail-range : specifies available frequency range(min/max) for APB clock
> +- ufs,pwr-attr-mode : specifies mode value for power mode change, possible values are
> +			"FAST", "SLOW", "FAST_auto" and "SLOW_auto"

Anything before the ',' is considered a vendor prefix and 'ufs' is not a 
vendor.

If these are standard UFS properties, then they should be documented in 
a common UFS binding. On the flip side, none of the other UFS bindings 
have needed these properties, so why do you?

> +- ufs,pwr-attr-lane : specifies lane count value for power mode change
> +		      allowed values are 1 or 2
> +- ufs,pwr-attr-gear : specifies gear count value for power mode change
> +		      allowed values are 1 or 2
> +- ufs,pwr-attr-hs-series : specifies HS rate series for power mode change
> +			   can be one of "HS_rate_b" or "HS_rate_a"
> +- ufs,pwr-local-l2-timer : specifies array of local UNIPRO L2 timer values
> +			   3 timers supported
> +			   <FC0ProtectionTimeOutVal,TC0ReplayTimeOutVal, AFC0ReqTimeOutVal>
> +- ufs,pwr-remote-l2-timer : specifies array of remote UNIPRO L2 timer values
> +			   3 timers supported
> +			   <FC0ProtectionTimeOutVal,TC0ReplayTimeOutVal, AFC0ReqTimeOutVal>
> +- ufs-rx-adv-fine-gran-sup_en : specifies support of fine granularity of MPHY,
> +			      this is a boolean property.
> +- ufs-rx-adv-fine-gran-step : specifies granularity steps of MPHY,
> +			      allowed step size is 0 to 3
> +- ufs-rx-adv-min-activate-time-cap : specifies rx advanced minimum activate time of MPHY
> +				     range is 1 to 9
> +- ufs-pa-granularity : specifies Granularity for PA_TActivate and PA_Hibern8Time
> +- ufs-pa-tacctivate : specifies time to wake-up remote M-RX
> +- ufs-pa-hibern8time : specifies minimum time to wait in HIBERN8 state
> +
> +Note: If above properties are not defined it can be assumed that the supply
> +regulators or clocks are always on.
> +
> +Example:
> +	ufshc@0x15570000 {
> +		compatible = "samsung,exynos7-ufs";
> +		reg = <0x15570000 0x100>,
> +		      <0x15570100 0x100>,
> +		      <0x15571000 0x200>,
> +		      <0x15572000 0x300>;
> +		reg-names = "hci", "vs_hci", "unipro", "ufsp";
> +		interrupts = <0 200 0>;
> +
> +		vdd-hba-supply = <&xxx_reg0>;
> +		vdd-hba-fixed-regulator;
> +		vcc-supply = <&xxx_reg1>;
> +		vcc-supply-1p8;
> +		vccq-supply = <&xxx_reg2>;
> +		vccq2-supply = <&xxx_reg3>;
> +		vcc-max-microamp = 500000;
> +		vccq-max-microamp = 200000;
> +		vccq2-max-microamp = 200000;
> +
> +		clocks = <&core 0>, <&ref 0>, <&iface 0>;
> +		clock-names = "core", "sclk_unipro_main", "ref", "ref_parent";
> +		freq-table-hz = <100000000 200000000>, <0 0>, <0 0>, <0 0>;
> +
> +		pclk-freq-avail-range = <70000000 133000000>;
> +
> +		ufs,pwr-attr-mode = "FAST";
> +		ufs,pwr-attr-lane = <2>;
> +		ufs,pwr-attr-gear = <2>;
> +		ufs,pwr-attr-hs-series = "HS_rate_b";
> +		ufs,pwr-local-l2-timer = <8000 28000 20000>;
> +		ufs,pwr-remote-l2-timer = <12000 32000 16000>;
> +		ufs-rx-adv-fine-gran-sup_en = <1>;
> +		ufs-rx-adv-fine-gran-step = <3>;
> +		ufs-rx-adv-min-activate-time-cap = <9>;
> +		ufs-pa-granularity = <6>;
> +		ufs-pa-tacctivate = <6>;
> +		ufs-pa-hibern8time = <20>;
> +	};
> -- 
> 2.17.1
>