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Message-ID: <c119a70d-b7ef-ab1b-4590-7ac77395297f@linux.intel.com>
Date: Tue, 25 Feb 2020 15:38:12 +0800
From: "Ramuthevar, Vadivel MuruganX"
<vadivel.muruganx.ramuthevar@...ux.intel.com>
To: Vignesh Raghavendra <vigneshr@...com>,
Rob Herring <robh+dt@...nel.org>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
linux-spi <linux-spi@...r.kernel.org>,
Mark Brown <broonie@...nel.org>,
simon.k.r.goldschmidt@...il.com, Dinh Nguyen <dinguyen@...nel.org>,
tien.fong.chee@...el.com,
Marek Vašut <marex@...x.de>,
cheol.yong.kim@...el.com, qi-ming.wu@...el.com
Subject: Re: [PATCH v10 1/2] dt-bindings: spi: Add schema for Cadence QSPI
Controller driver
Hi,
On 25/2/2020 2:41 PM, Vignesh Raghavendra wrote:
>
> On 25/02/20 11:54 am, Ramuthevar, Vadivel MuruganX wrote:
>> Hi Rob,
>>
>> Thank you for the review comments...
>>
>> On 24/2/2020 11:54 PM, Rob Herring wrote:
>>> On Tue, Feb 18, 2020 at 8:29 PM Ramuthevar,Vadivel MuruganX
>>> <vadivel.muruganx.ramuthevar@...ux.intel.com> wrote:
>>>> From: Ramuthevar Vadivel Murugan
>>>> <vadivel.muruganx.ramuthevar@...ux.intel.com>
>>> Cc the DT list if you want this reviewed.
>> Sorry, next patch will add DT list in CC.
>>>> Add dt-bindings documentation for Cadence-QSPI controller to support
>>>> spi based flash memories.
>>>>
>>>> Signed-off-by: Ramuthevar Vadivel Murugan
>>>> <vadivel.muruganx.ramuthevar@...ux.intel.com>
>>>> ---
>>>> .../devicetree/bindings/spi/cdns,qspi-nor.yaml | 147
>>>> +++++++++++++++++++++
>>>> 1 file changed, 147 insertions(+)
>>>> create mode 100644
>>>> Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
>>>> b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
>>>> new file mode 100644
>>>> index 000000000000..1a4d6e8d0d0b
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
>>>> @@ -0,0 +1,147 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: "http://devicetree.org/schemas/spi/cdns,qspi-nor.yaml#"
>>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>>>> +
>>>> +title: Cadence QSPI Flash Controller support
>>>> +
>>>> +maintainers:
>>>> + - Ramuthevar Vadivel Murugan
>>>> <vadivel.muruganx.ramuthevar@...ux.intel.com>
>>>> +
>>>> +allOf:
>>>> + - $ref: "spi-controller.yaml#"
>>>> +
>>>> +description: |
>>>> + Binding Documentation for Cadence QSPI controller,This controller is
>>>> + present in the Intel LGM, Altera SoCFPGA and TI SoCs and this driver
>>>> + has been tested On Intel's LGM SoC.
>>>> +
>>>> + - compatible : should be one of the following:
>>>> + Generic default - "cdns,qspi-nor".
>>>> + For TI 66AK2G SoC - "ti,k2g-qspi", "cdns,qspi-nor".
>>>> + For TI AM654 SoC - "ti,am654-ospi", "cdns,qspi-nor".
>>>> + For Intel LGM SoC - "intel,lgm-qspi", "cdns,qspi-nor".
>>>> +
>>>> +properties:
>>>> + compatible:
>>>> + oneOf:
>>>> + - items:
>>>> + - enum:
>>>> + - ti,k2g-qspi
>>>> + - const: cdns,qspi-nor
>>>> +
>>>> + - items:
>>>> + - enum:
>>>> + - ti,am654-ospi
>>>> + - const: cdns,qspi-nor
>>>> +
>>>> + - items:
>>>> + - enum:
>>>> + - intel,lgm-qspi
>>>> + - const: cdns,qspi-nor
>>>> +
>>>> + - items:
>>>> + - const: cdns,qspi-nor
>>>> +
>>>> + reg:
>>>> + maxItems: 2
>>>> +
>>>> + interrupts:
>>>> + maxItems: 1
>>>> +
>>>> + clocks:
>>>> + maxItems: 1
>>>> +
>>>> + cdns,fifo-depth:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description:
>>>> + Size of the data FIFO in words.
>>> A 4GB fifo is valid? Add some constraints.
>> 128 is valid, will update.
> Nope, the width of this field is 8bits -> 256 bytes
correct me if I am wrong, the width of this field is 4bits -> 128 bytes
(based on QUAD mode) .
>>>> +
>>>> + cdns,fifo-width:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description:
>>>> + Bus width of the data FIFO in bytes.
>>> Add some constraints.
>> 4 is valid , will fix it.
>>>> +
>>>> + cdns,trigger-address:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description:
>>>> + 32-bit indirect AHB trigger address.
>>>> +
>>>> + cdns,rclk-en:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description: |
>>>> + Flag to indicate that QSPI return clock is used to latch the
>>>> read data
>>>> + rather than the QSPI clock. Make sure that QSPI return clock
>>>> is populated
>>>> + on the board before using this property.
>>>> +
>>>> +# subnode's properties
>>>> +patternProperties:
>>>> + "^.*@[0-9a-fA-F]+$":
>>>> + type: object
>>>> + description:
>>>> + flash device uses the subnodes below defined properties.
>>>> +
>>>> + cdns,read-delay:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description:
>>>> + Delay for read capture logic, in clock cycles.
>>> 4 billion clock delay is valid?
>> based on the ref_clk , will add it.
>>>> +
>>>> + cdns,tshsl-ns:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>> You can drop this, anything with a standard unit suffix already has a
>>> type.
>> sure , will drop it.
>>>> + description: |
>>>> + Delay in nanoseconds for the length that the master mode chip
>>>> select
>>>> + outputs are de-asserted between transactions.
>>> Constraints...?
>> 50ns, will add it.
>>
> This really depends on the input clk:
>
> Clock Delay for Chip Select Deassert:
>
> Delay in master reference clocks for the length that the master mode
>
> chip select outputs are de-asserted between transactions The
>
> minimum delay is always SCLK period to ensure the chip select is
>
> never re-asserted within an SCLK period.
>
> I don't see a easy way of verifying constraints in yaml.
>
> Same applies for below 3 properties as well.
Thank you vignesh for the detailed explanation.
Regards
Vadivel
> Regards
> Vignesh
>
>> Regards
>> Vadivel
>>>> +
>>>> + cdns,tsd2d-ns:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description: |
>>>> + Delay in nanoseconds between one chip select being de-activated
>>>> + and the activation of another.
>>>> +
>>>> + cdns,tchsh-ns:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description: |
>>>> + Delay in nanoseconds between last bit of current transaction and
>>>> + deasserting the device chip select (qspi_n_ss_out).
>>>> +
>>>> + cdns,tslch-ns:
>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>> + description: |
>>>> + Delay in nanoseconds between setting qspi_n_ss_out low and
>>>> + first bit transfer.
>>>> +
>>>> +required:
>>>> + - compatible
>>>> + - reg
>>>> + - interrupts
>>>> + - clocks
>>>> + - cdns,fifo-depth
>>>> + - cdns,fifo-width
>>>> + - cdns,trigger-address
>>>> +
>>>> +examples:
>>>> + - |
>>>> + qspi: spi@...05000 {
>>>> + compatible = "cdns,qspi-nor";
>>>> + #address-cells = <1>;
>>>> + #size-cells = <0>;
>>>> + reg = <0xff705000 0x1000>,
>>>> + <0xffa00000 0x1000>;
>>>> + interrupts = <0 151 4>;
>>>> + clocks = <&qspi_clk>;
>>>> + cdns,fifo-depth = <128>;
>>>> + cdns,fifo-width = <4>;
>>>> + cdns,trigger-address = <0x00000000>;
>>>> +
>>>> + flash0: n25q00@0 {
>>>> + compatible = "jedec,spi-nor";
>>>> + reg = <0x0>;
>>>> + cdns,read-delay = <4>;
>>>> + cdns,tshsl-ns = <50>;
>>>> + cdns,tsd2d-ns = <50>;
>>>> + cdns,tchsh-ns = <4>;
>>>> + cdns,tslch-ns = <4>;
>>>> + };
>>>> + };
>>>> +
>>>> --
>>>> 2.11.0
>>>>
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