diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-11 23:19:47 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-11 23:19:47 +0300 |
commit | 282aa44c21708835517ffaa31c63ab651248cf5e (patch) | |
tree | 43b9b3a257da33031144d1481afdedf1ba00d20a /Documentation | |
parent | fef8dfaea9d6c444b6c2174b3a2b0fca4d226c5e (diff) | |
parent | 19629ae482f1800b50a5bdf2504ac57171d2bb82 (diff) | |
download | linux-282aa44c21708835517ffaa31c63ab651248cf5e.tar.xz |
Merge tag 'spi-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi
Pull spi updates from Mark Brown:
"This has mostly been a quiet release for the SPI subsystem, almost all
cleanups and fixes to existing drivers.
A couple of changes that stand out:
- Cleanups and support for version specific features in the
DesignWare controller.
- Removal of support for Netlogic devices from the XLP driver, the
platform had previously been removed by MIPS so the support
couldn't be used.
- Conversion of several DT bindings to YAML format"
* tag 'spi-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (53 commits)
spi: don't include ptp_clock_kernel.h in spi.h
spi: spi-meson-spifc: Add missing pm_runtime_disable() in meson_spifc_probe
spi: atmel: Fix typo
spi: dt-bindings: mediatek,spi-mtk-nor: Fix example 'interrupts' property
spi: qcom: geni: handle timeout for gpi mode
spi: qcom: geni: set the error code for gpi transfer
spi: spi-mux: Add reference to spi-peripheral-props.yaml schema
spi: ar934x: fix transfer size
spi: pxa2xx: Propagate firmware node
spi: dw: Propagate firmware node
spi: dln2: Propagate firmware node
spi: ar934x: fix transfer and word delays
spi: uniphier: Fix a bug that doesn't point to private data correctly
spi: spi-mtk-nor: add new clock name 'axi' for spi nor
spi: atmel,quadspi: Define sama7g5 QSPI
spi: atmel,quadspi: Convert to json-schema
spi: Fix incorrect cs_setup delay handling
dt-bindings: mtd: spi-nor: Add a reference to spi-peripheral-props.yaml
spi: dt-bindings: cdns,qspi-nor: Move peripheral-specific properties out
spi: dt-bindings: add schema listing peripheral-specific properties
...
Diffstat (limited to 'Documentation')
14 files changed, 300 insertions, 192 deletions
diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml index ed590d7c6e37..39421f7233e4 100644 --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml @@ -11,6 +11,7 @@ maintainers: allOf: - $ref: "mtd.yaml#" + - $ref: /schemas/spi/spi-peripheral-props.yaml# properties: compatible: @@ -88,7 +89,7 @@ patternProperties: "^otp(-[0-9]+)?$": type: object -additionalProperties: false +unevaluatedProperties: false examples: - | diff --git a/Documentation/devicetree/bindings/spi/atmel,quadspi.yaml b/Documentation/devicetree/bindings/spi/atmel,quadspi.yaml new file mode 100644 index 000000000000..1d493add4053 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/atmel,quadspi.yaml @@ -0,0 +1,99 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/spi/atmel,quadspi.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Atmel Quad Serial Peripheral Interface (QSPI) + +maintainers: + - Tudor Ambarus <tudor.ambarus@microchip.com> + +allOf: + - $ref: spi-controller.yaml# + +properties: + compatible: + enum: + - atmel,sama5d2-qspi + - microchip,sam9x60-qspi + - microchip,sama7g5-qspi + - microchip,sama7g5-ospi + + reg: + items: + - description: base registers + - description: mapped memory + + reg-names: + items: + - const: qspi_base + - const: qspi_mmap + + clocks: + minItems: 1 + items: + - description: peripheral clock + - description: system clock or generic clock, if available + + clock-names: + minItems: 1 + items: + - const: pclk + - enum: [ qspick, gclk ] + + interrupts: + maxItems: 1 + + dmas: + items: + - description: tx DMA channel + - description: rx DMA channel + + dma-names: + items: + - const: tx + - const: rx + + '#address-cells': + const: 1 + + '#size-cells': + const: 0 + +required: + - compatible + - reg + - reg-names + - interrupts + - clocks + - clock-names + - '#address-cells' + - '#size-cells' + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/interrupt-controller/irq.h> + #include <dt-bindings/clock/at91.h> + spi@f0020000 { + compatible = "atmel,sama5d2-qspi"; + reg = <0xf0020000 0x100>, <0xd0000000 0x8000000>; + reg-names = "qspi_base", "qspi_mmap"; + interrupts = <52 IRQ_TYPE_LEVEL_HIGH 7>; + clocks = <&pmc PMC_TYPE_PERIPHERAL 52>; + clock-names = "pclk"; + #address-cells = <1>; + #size-cells = <0>; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_spi0_default>; + + flash@0 { + compatible = "jedec,spi-nor"; + spi-max-frequency = <50000000>; + reg = <0>; + spi-rx-bus-width = <4>; + spi-tx-bus-width = <4>; + }; + }; diff --git a/Documentation/devicetree/bindings/spi/atmel-quadspi.txt b/Documentation/devicetree/bindings/spi/atmel-quadspi.txt deleted file mode 100644 index 7c40ea694352..000000000000 --- a/Documentation/devicetree/bindings/spi/atmel-quadspi.txt +++ /dev/null @@ -1,37 +0,0 @@ -* Atmel Quad Serial Peripheral Interface (QSPI) - -Required properties: -- compatible: Should be one of the following: - - "atmel,sama5d2-qspi" - - "microchip,sam9x60-qspi" -- reg: Should contain the locations and lengths of the base registers - and the mapped memory. -- reg-names: Should contain the resource reg names: - - qspi_base: configuration register address space - - qspi_mmap: memory mapped address space -- interrupts: Should contain the interrupt for the device. -- clocks: Should reference the peripheral clock and the QSPI system - clock if available. -- clock-names: Should contain "pclk" for the peripheral clock and "qspick" - for the system clock when available. -- #address-cells: Should be <1>. -- #size-cells: Should be <0>. - -Example: - -spi@f0020000 { - compatible = "atmel,sama5d2-qspi"; - reg = <0xf0020000 0x100>, <0xd0000000 0x8000000>; - reg-names = "qspi_base", "qspi_mmap"; - interrupts = <52 IRQ_TYPE_LEVEL_HIGH 7>; - clocks = <&pmc PMC_TYPE_PERIPHERAL 52>; - clock-names = "pclk"; - #address-cells = <1>; - #size-cells = <0>; - pinctrl-names = "default"; - pinctrl-0 = <&pinctrl_spi0_default>; - - m25p80@0 { - ... - }; -}; diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/cdns,qspi-nor-peripheral-props.yaml new file mode 100644 index 000000000000..553601a441a7 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor-peripheral-props.yaml @@ -0,0 +1,42 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/spi/cdns,qspi-nor-peripheral-props.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Peripheral-specific properties for the Cadence QSPI controller. + +description: + See spi-peripheral-props.yaml for more info. + +maintainers: + - Pratyush Yadav <p.yadav@ti.com> + +properties: + # cdns,qspi-nor.yaml + cdns,read-delay: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + Delay for read capture logic, in clock cycles. + + cdns,tshsl-ns: + description: + Delay in nanoseconds for the length that the master mode chip select + outputs are de-asserted between transactions. + + cdns,tsd2d-ns: + description: + Delay in nanoseconds between one chip select being de-activated + and the activation of another. + + cdns,tchsh-ns: + description: + Delay in nanoseconds between last bit of current transaction and + deasserting the device chip select (qspi_n_ss_out). + + cdns,tslch-ns: + description: + Delay in nanoseconds between setting qspi_n_ss_out low and + first bit transfer. + +additionalProperties: true diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml index 037f41f58503..0a537fa3a641 100644 --- a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml +++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml @@ -87,39 +87,6 @@ properties: items: enum: [ qspi, qspi-ocp ] -# subnode's properties -patternProperties: - "@[0-9a-f]+$": - type: object - description: - Flash device uses the below defined properties in the subnode. - - properties: - cdns,read-delay: - $ref: /schemas/types.yaml#/definitions/uint32 - description: - Delay for read capture logic, in clock cycles. - - cdns,tshsl-ns: - description: - Delay in nanoseconds for the length that the master mode chip select - outputs are de-asserted between transactions. - - cdns,tsd2d-ns: - description: - Delay in nanoseconds between one chip select being de-activated - and the activation of another. - - cdns,tchsh-ns: - description: - Delay in nanoseconds between last bit of current transaction and - deasserting the device chip select (qspi_n_ss_out). - - cdns,tslch-ns: - description: - Delay in nanoseconds between setting qspi_n_ss_out low and - first bit transfer. - required: - compatible - reg diff --git a/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-nor.yaml b/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-nor.yaml index 7393f30535df..4e4694e3d539 100644 --- a/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-nor.yaml +++ b/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-nor.yaml @@ -43,14 +43,19 @@ properties: maxItems: 1 clocks: + minItems: 2 items: - description: clock used for spi bus - description: clock used for controller + - description: clock used for nor dma bus. this depends on hardware + design, so this is optional. clock-names: + minItems: 2 items: - const: spi - const: sf + - const: axi required: - compatible @@ -72,7 +77,7 @@ examples: nor_flash: spi@1100d000 { compatible = "mediatek,mt8173-nor"; reg = <0 0x1100d000 0 0xe0>; - interrupts = <&spi_flash_irq>; + interrupts = <1>; clocks = <&pericfg CLK_PERI_SPI>, <&topckgen CLK_TOP_SPINFI_IFR_SEL>; clock-names = "spi", "sf"; #address-cells = <1>; @@ -84,4 +89,3 @@ examples: }; }; }; - diff --git a/Documentation/devicetree/bindings/spi/renesas,rspi.yaml b/Documentation/devicetree/bindings/spi/renesas,rspi.yaml index 8397f60d80a2..76e6d9e52fc7 100644 --- a/Documentation/devicetree/bindings/spi/renesas,rspi.yaml +++ b/Documentation/devicetree/bindings/spi/renesas,rspi.yaml @@ -21,7 +21,8 @@ properties: - enum: - renesas,rspi-r7s72100 # RZ/A1H - renesas,rspi-r7s9210 # RZ/A2 - - const: renesas,rspi-rz # RZ/A + - renesas,r9a07g044-rspi # RZ/G2{L,LC} + - const: renesas,rspi-rz # RZ/A and RZ/G2{L,LC} - items: - enum: @@ -122,6 +123,7 @@ allOf: contains: enum: - renesas,qspi + - renesas,r9a07g044-rspi then: required: - resets diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml index 8246891602e7..36b72518f565 100644 --- a/Documentation/devicetree/bindings/spi/spi-controller.yaml +++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml @@ -94,73 +94,8 @@ patternProperties: "^.*@[0-9a-f]+$": type: object - properties: - compatible: - description: - Compatible of the SPI device. - - reg: - minItems: 1 - maxItems: 256 - items: - minimum: 0 - maximum: 256 - description: - Chip select used by the device. - - spi-3wire: - $ref: /schemas/types.yaml#/definitions/flag - description: - The device requires 3-wire mode. - - spi-cpha: - $ref: /schemas/types.yaml#/definitions/flag - description: - The device requires shifted clock phase (CPHA) mode. - - spi-cpol: - $ref: /schemas/types.yaml#/definitions/flag - description: - The device requires inverse clock polarity (CPOL) mode. - - spi-cs-high: - $ref: /schemas/types.yaml#/definitions/flag - description: - The device requires the chip select active high. - - spi-lsb-first: - $ref: /schemas/types.yaml#/definitions/flag - description: - The device requires the LSB first mode. - - spi-max-frequency: - $ref: /schemas/types.yaml#/definitions/uint32 - description: - Maximum SPI clocking speed of the device in Hz. - - spi-rx-bus-width: - description: - Bus width to the SPI bus used for read transfers. - If 0 is provided, then no RX will be possible on this device. - $ref: /schemas/types.yaml#/definitions/uint32 - enum: [0, 1, 2, 4, 8] - default: 1 - - spi-rx-delay-us: - description: - Delay, in microseconds, after a read transfer. - - spi-tx-bus-width: - description: - Bus width to the SPI bus used for write transfers. - If 0 is provided, then no TX will be possible on this device. - $ref: /schemas/types.yaml#/definitions/uint32 - enum: [0, 1, 2, 4, 8] - default: 1 - - spi-tx-delay-us: - description: - Delay, in microseconds, after a write transfer. + allOf: + - $ref: spi-peripheral-props.yaml required: - compatible diff --git a/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml b/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml index 312d8fee9dbb..1d46877fe46a 100644 --- a/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml +++ b/Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml @@ -14,10 +14,13 @@ allOf: properties: compatible: - enum: - - fsl,imx7ulp-spi - - fsl,imx8qxp-spi - + oneOf: + - enum: + - fsl,imx7ulp-spi + - fsl,imx8qxp-spi + - items: + - const: fsl,imx8ulp-spi + - const: fsl,imx7ulp-spi reg: maxItems: 1 diff --git a/Documentation/devicetree/bindings/spi/spi-mux.yaml b/Documentation/devicetree/bindings/spi/spi-mux.yaml index 51c7622dc20b..7ea79f6d33f3 100644 --- a/Documentation/devicetree/bindings/spi/spi-mux.yaml +++ b/Documentation/devicetree/bindings/spi/spi-mux.yaml @@ -31,6 +31,7 @@ description: | allOf: - $ref: "/schemas/spi/spi-controller.yaml#" + - $ref: "/schemas/spi/spi-peripheral-props.yaml#" maintainers: - Chris Packham <chris.packham@alliedtelesis.co.nz> diff --git a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml new file mode 100644 index 000000000000..5dd209206e88 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml @@ -0,0 +1,89 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/spi/spi-peripheral-props.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Peripheral-specific properties for a SPI bus. + +description: + Many SPI controllers need to add properties to peripheral devices. They could + be common properties like spi-max-frequency, spi-cpha, etc. or they could be + controller specific like delay in clock or data lines, etc. These properties + need to be defined in the peripheral node because they are per-peripheral and + there can be multiple peripherals attached to a controller. All those + properties are listed here. The controller specific properties should go in + their own separate schema that should be referenced from here. + +maintainers: + - Pratyush Yadav <p.yadav@ti.com> + +properties: + reg: + minItems: 1 + maxItems: 256 + items: + minimum: 0 + maximum: 256 + description: + Chip select used by the device. + + spi-3wire: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires 3-wire mode. + + spi-cpha: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires shifted clock phase (CPHA) mode. + + spi-cpol: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires inverse clock polarity (CPOL) mode. + + spi-cs-high: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires the chip select active high. + + spi-lsb-first: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires the LSB first mode. + + spi-max-frequency: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + Maximum SPI clocking speed of the device in Hz. + + spi-rx-bus-width: + description: + Bus width to the SPI bus used for read transfers. + If 0 is provided, then no RX will be possible on this device. + $ref: /schemas/types.yaml#/definitions/uint32 + enum: [0, 1, 2, 4, 8] + default: 1 + + spi-rx-delay-us: + description: + Delay, in microseconds, after a read transfer. + + spi-tx-bus-width: + description: + Bus width to the SPI bus used for write transfers. + If 0 is provided, then no TX will be possible on this device. + $ref: /schemas/types.yaml#/definitions/uint32 + enum: [0, 1, 2, 4, 8] + default: 1 + + spi-tx-delay-us: + description: + Delay, in microseconds, after a write transfer. + +# The controller specific properties go here. +allOf: + - $ref: cdns,qspi-nor-peripheral-props.yaml# + +additionalProperties: true diff --git a/Documentation/devicetree/bindings/spi/spi-pl022.yaml b/Documentation/devicetree/bindings/spi/spi-pl022.yaml index a91d868e40c5..6d633728fc2b 100644 --- a/Documentation/devicetree/bindings/spi/spi-pl022.yaml +++ b/Documentation/devicetree/bindings/spi/spi-pl022.yaml @@ -72,6 +72,9 @@ properties: - const: rx - const: tx + resets: + maxItems: 1 + patternProperties: "^[a-zA-Z][a-zA-Z0-9,+\\-._]{0,63}@[0-9a-f]+$": type: object diff --git a/Documentation/spi/pxa2xx.rst b/Documentation/spi/pxa2xx.rst index 6312968acfe9..6347580826be 100644 --- a/Documentation/spi/pxa2xx.rst +++ b/Documentation/spi/pxa2xx.rst @@ -101,8 +101,7 @@ device. All fields are optional. u8 rx_threshold; u8 dma_burst_size; u32 timeout; - u8 enable_loopback; - void (*cs_control)(u32 command); + int gpio_cs; }; The "pxa2xx_spi_chip.tx_threshold" and "pxa2xx_spi_chip.rx_threshold" fields are @@ -128,16 +127,6 @@ dependent on the SPI bus speed ("spi_board_info.max_speed_hz") and the specific slave device. Please note that the PXA2xx SSP 1 does not support trailing byte timeouts and must busy-wait any trailing bytes. -The "pxa2xx_spi_chip.enable_loopback" field is used to place the SSP porting -into internal loopback mode. In this mode the SSP controller internally -connects the SSPTX pin to the SSPRX pin. This is useful for initial setup -testing. - -The "pxa2xx_spi_chip.cs_control" field is used to point to a board specific -function for asserting/deasserting a slave device chip select. If the field is -NULL, the pxa2xx_spi master controller driver assumes that the SSP port is -configured to use GPIO or SSPFRM instead. - NOTE: the SPI driver cannot control the chip select if SSPFRM is used, so the chipselect is dropped after each spi_transfer. Most devices need chip select asserted around the complete message. Use SSPFRM as a GPIO (through a descriptor) @@ -152,30 +141,12 @@ field. Below is a sample configuration using the PXA255 NSSP. :: - /* Chip Select control for the CS8415A SPI slave device */ - static void cs8415a_cs_control(u32 command) - { - if (command & PXA2XX_CS_ASSERT) - GPCR(2) = GPIO_bit(2); - else - GPSR(2) = GPIO_bit(2); - } - - /* Chip Select control for the CS8405A SPI slave device */ - static void cs8405a_cs_control(u32 command) - { - if (command & PXA2XX_CS_ASSERT) - GPCR(3) = GPIO_bit(3); - else - GPSR(3) = GPIO_bit(3); - } - static struct pxa2xx_spi_chip cs8415a_chip_info = { .tx_threshold = 8, /* SSP hardward FIFO threshold */ .rx_threshold = 8, /* SSP hardward FIFO threshold */ .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */ .timeout = 235, /* See Intel documentation */ - .cs_control = cs8415a_cs_control, /* Use external chip select */ + .gpio_cs = 2, /* Use external chip select */ }; static struct pxa2xx_spi_chip cs8405a_chip_info = { @@ -183,7 +154,7 @@ field. Below is a sample configuration using the PXA255 NSSP. .rx_threshold = 8, /* SSP hardward FIFO threshold */ .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */ .timeout = 235, /* See Intel documentation */ - .cs_control = cs8405a_cs_control, /* Use external chip select */ + .gpio_cs = 3, /* Use external chip select */ }; static struct spi_board_info streetracer_spi_board_info[] __initdata = { diff --git a/Documentation/spi/spidev.rst b/Documentation/spi/spidev.rst index f05dbc5ccdbc..369c657ba435 100644 --- a/Documentation/spi/spidev.rst +++ b/Documentation/spi/spidev.rst @@ -29,21 +29,49 @@ of the driver stack) that are not accessible to userspace. DEVICE CREATION, DRIVER BINDING =============================== -The simplest way to arrange to use this driver is to just list it in the -spi_board_info for a device as the driver it should use: the "modalias" -entry is "spidev", matching the name of the driver exposing this API. -Set up the other device characteristics (bits per word, SPI clocking, -chipselect polarity, etc) as usual, so you won't always need to override -them later. - -(Sysfs also supports userspace driven binding/unbinding of drivers to -devices. That mechanism might be supported here in the future.) - -When you do that, the sysfs node for the SPI device will include a child -device node with a "dev" attribute that will be understood by udev or mdev. -(Larger systems will have "udev". Smaller ones may configure "mdev" into -busybox; it's less featureful, but often enough.) For a SPI device with -chipselect C on bus B, you should see: + +The spidev driver contains lists of SPI devices that are supported for +the different hardware topology representations. + +The following are the SPI device tables supported by the spidev driver: + + - struct spi_device_id spidev_spi_ids[]: list of devices that can be + bound when these are defined using a struct spi_board_info with a + .modalias field matching one of the entries in the table. + + - struct of_device_id spidev_dt_ids[]: list of devices that can be + bound when these are defined using a Device Tree node that has a + compatible string matching one of the entries in the table. + + - struct acpi_device_id spidev_acpi_ids[]: list of devices that can + be bound when these are defined using a ACPI device object with a + _HID matching one of the entries in the table. + +You are encouraged to add an entry for your SPI device name to relevant +tables, if these don't already have an entry for the device. To do that, +post a patch for spidev to the linux-spi@vger.kernel.org mailing list. + +It used to be supported to define an SPI device using the "spidev" name. +For example, as .modalias = "spidev" or compatible = "spidev". But this +is no longer supported by the Linux kernel and instead a real SPI device +name as listed in one of the tables must be used. + +Not having a real SPI device name will lead to an error being printed and +the spidev driver failing to probe. + +Sysfs also supports userspace driven binding/unbinding of drivers to +devices that do not bind automatically using one of the tables above. +To make the spidev driver bind to such a device, use the following: + + echo spidev > /sys/bus/spi/devices/spiB.C/driver_override + echo spiB.C > /sys/bus/spi/drivers/spidev/bind + +When the spidev driver is bound to a SPI device, the sysfs node for the +device will include a child device node with a "dev" attribute that will +be understood by udev or mdev (udev replacement from BusyBox; it's less +featureful, but often enough). + +For a SPI device with chipselect C on bus B, you should see: /dev/spidevB.C ... character special device, major number 153 with |