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linux-next/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
Subhash Jadavani 9e1e8a7570 scsi: ufs: set the device reference clock setting
UFS host supplies the reference clock to UFS device and UFS device
specification allows host to provide one of the 4 frequencies (19.2 MHz, 26
MHz, 38.4 MHz, 52 MHz) for reference clock. Host should set the device
reference clock frequency setting in the device based on what frequency it
is supplying to UFS device.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-11-09 07:52:59 -05:00

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* 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 : must contain "jedec,ufs-1.1" or "jedec,ufs-2.0", may
also list one or more of the following:
"qcom,msm8994-ufshc"
"qcom,msm8996-ufshc"
"qcom,ufshc"
- interrupts : <interrupt mapping for UFS host controller IRQ>
- reg : <registers mapping>
Optional properties:
- phys : phandle to UFS PHY node
- phy-names : the string "ufsphy" when is found in a node, along
with "phys" attribute, provides phandle to UFS PHY node
- 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.
- 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
- <name>-fixed-regulator : boolean property specifying that <name>-supply is a fixed regulator
- 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.
"ref_clk" indicates reference clock frequency.
UFS host supplies reference clock to UFS device and UFS device
specification allows host to provide one of the 4 frequencies (19.2 MHz,
26 MHz, 38.4 MHz, 52MHz) for reference clock. This "ref_clk" entry is
parsed and used to update the reference clock setting in device.
Defaults to 26 MHz(as per specification) if not specified by host.
- 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.
-lanes-per-direction : number of lanes available per direction - either 1 or 2.
Note that it is assume same number of lanes is used both
directions at once. If not specified, default is 2 lanes per direction.
- resets : reset node register
- reset-names : describe reset node register, the "rst" corresponds to reset the whole UFS IP.
Note: If above properties are not defined it can be assumed that the supply
regulators or clocks are always on.
Example:
ufshc@fc598000 {
compatible = "jedec,ufs-1.1";
reg = <0xfc598000 0x800>;
interrupts = <0 28 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>, <&phy 0>, <&iface 0>;
clock-names = "core_clk", "ref_clk", "phy_clk", "iface_clk";
freq-table-hz = <100000000 200000000>, <0 0>, <0 0>, <0 0>;
resets = <&reset 0 1>;
reset-names = "rst";
phys = <&ufsphy1>;
phy-names = "ufsphy";
};