From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Ayush Singh <ayushdevel1325@gmail.com>,
Michael Walle <mwalle@kernel.org>,
open list <linux-kernel@vger.kernel.org>
Cc: jkridner@beagleboard.org, robertcnelson@beagleboard.org,
lorforlinux@beagleboard.org, Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Conor Dooley <conor+dt@kernel.org>, Nishanth Menon <nm@ti.com>,
Vignesh Raghavendra <vigneshr@ti.com>,
Tero Kristo <kristo@kernel.org>,
Derek Kiernan <derek.kiernan@amd.com>,
Dragan Cvetic <dragan.cvetic@amd.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Vaishnav M A <vaishnav.a@ti.com>, Mark Brown <broonie@kernel.org>,
Johan Hovold <johan@kernel.org>, Alex Elder <elder@kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
"moderated list:ARM/TEXAS INSTRUMENTS K3 ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>,
"open list:SPI SUBSYSTEM" <linux-spi@vger.kernel.org>,
"moderated list:GREYBUS SUBSYSTEM" <greybus-dev@lists.linaro.org>,
Vaishnav M A <vaishnav@beagleboard.org>
Subject: Re: [PATCH v4 1/5] dt-bindings: misc: Add mikrobus-connector
Date: Tue, 19 Mar 2024 06:58:16 +0100 [thread overview]
Message-ID: <0f3f56d4-3381-44f1-91bc-c126f3ced085@linaro.org> (raw)
In-Reply-To: <d4dc4d94-d323-4158-8c08-b7d37d8750d3@gmail.com>
On 18/03/2024 18:20, Ayush Singh wrote:
> On 3/18/24 17:52, Michael Walle wrote:
>
>> On Sun Mar 17, 2024 at 8:37 PM CET, Ayush Singh wrote:
>>> Add DT bindings for mikroBUS interface. MikroBUS is an open standard
>>> developed by MikroElektronika for connecting add-on boards to
>>> microcontrollers or microprocessors.
>>>
>>> mikroBUS is a connector and does not have a controller. Instead the
>>> software is responsible for identification of board and setting up /
>>> registering uart, spi, i2c, pwm and other buses. Thus it needs a way to
>>> get uart, spi, i2c, pwm and gpio controllers / adapters.
>>>
>>> A mikroBUS addon board is free to leave some of the pins unused which
>>> are marked as NC or Not Connected.
>>>
>>> Some of the pins might need to be configured as GPIOs deviating from their
>>> reserved purposes Eg: SHT15 Click where the SCL and SDA Pins need to be
>>> configured as GPIOs for the driver (drivers/hwmon/sht15.c) to work.
>>>
>>> For some add-on boards the driver may not take care of some additional
>>> signals like reset/wake-up/other. Eg: ENC28J60 click where the reset line
>>> (RST pin on the mikrobus port) needs to be pulled high.
>>>
>>> Here's the list of pins in mikroBUS connector:
>>> Analog - AN
>>> Reset - RST
>>> SPI Chip Select - CS
>>> SPI Clock - SCK
>>> SPI Master Input Slave Output - MISO
>>> SPI Master Output Slave Input - MOSI
>>> VCC-3.3V power - +3.3V
>>> Reference Ground - GND
>>> PWM - PWM output
>>> INT - Hardware Interrupt
>>> RX - UART Receive
>>> TX - UART Transmit
>>> SCL - I2C Clock
>>> SDA - I2C Data
>>> +5V - VCC-5V power
>>> GND - Reference Ground
>>>
>>> Additionally, some new mikroBUS boards contain 1-wire EEPROM that contains
>>> a manifest to describe the addon board to provide plug and play
>>> capabilities.
>>>
>>> Link: https://www.mikroe.com/mikrobus
>>> Link:
>>> https://download.mikroe.com/documents/standards/mikrobus/mikrobus-standard-specification-v200.pdf
>>> mikroBUS specification
>>> Link: https://www.mikroe.com/sht1x-click SHT15 Click
>>> Link: https://www.mikroe.com/eth-click ENC28J60 Click
>>> Link: https://www.mikroe.com/clickid ClickID
>>>
>>> Co-developed-by: Vaishnav M A <vaishnav@beagleboard.org>
>>> Signed-off-by: Vaishnav M A <vaishnav@beagleboard.org>
>>> Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>
>>> ---
>>> .../connector/mikrobus-connector.yaml | 113 ++++++++++++++++++
>> See also
>> https://lore.kernel.org/r/YmFo+EntwxIsco%2Ft@robh.at.kernel.org/
>>
>> Looks like this proposal doesn't have the subnodes. How do you
>> attach a kernel driver to it's spi port for example? Only through
>> the manifest files?
>>
>> -michael
>
>
> So I looked at the Patch, and it seems the approach of fundamentally
> different than this PR. So, let me try to explain what this patch set
> does for an add-on board using SPI.
>
> The device tree defines the SPI controller associated with mikroBUS SPI
> pins. The driver on match queries and takes a reference to the SPI
> controller but does nothing with it. Once a mikroBUS add-on board is
> detected (by passing manifest using sysfs or reading from 1-wire
> EEPROM), the driver parses the manifest, and if it detects an SPI device
As I understood Mikrobus does not have EEPROM.
> in manifest, it registers SPI device along with setting properties such
> as `chip_select`, `max_speed_hz`, `mode`, etc., which are defined in the
> manifest. On board removal, it unregisters the SPI device and waits for
> a new mikroBUS board to be detected again.
You explained drivers, not hardware for DT.
>
> It is also possible for SPI not to be used by a device, in which case,
> no SPI device is registered to the controller. It is also possible that
> the SPI pins will be used as normal GPIOs. Everything is identified from
> the manifest.
Best regards,
Krzysztof
next prev parent reply other threads:[~2024-03-19 5:58 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-17 19:37 [PATCH v4 0/5] misc: Add mikroBUS driver Ayush Singh
2024-03-17 19:37 ` [PATCH v4 1/5] dt-bindings: misc: Add mikrobus-connector Ayush Singh
2024-03-18 12:22 ` Michael Walle
2024-03-18 17:20 ` Ayush Singh
2024-03-19 5:58 ` Krzysztof Kozlowski [this message]
2024-03-19 7:36 ` Ayush Singh
2024-03-19 9:38 ` Michael Walle
2024-03-19 11:36 ` Ayush Singh
2024-03-19 12:08 ` Michael Walle
2024-03-19 13:03 ` Ayush Singh
2024-03-19 14:21 ` Michael Walle
2024-03-19 17:19 ` Vaishnav Achath
2024-03-19 17:35 ` Ayush Singh
2024-03-19 19:32 ` Andrew Lunn
2024-03-20 16:39 ` Ayush Singh
2024-03-20 18:44 ` Andrew Lunn
2024-03-21 7:35 ` Vaishnav Achath
2024-03-21 12:31 ` Andrew Lunn
2024-03-19 12:25 ` Andrew Lunn
2024-03-19 17:35 ` Vaishnav Achath
2024-03-19 18:19 ` Conor Dooley
2024-03-21 6:30 ` Vaishnav Achath
2024-03-19 19:23 ` Andrew Lunn
2024-03-21 7:07 ` Vaishnav Achath
2024-03-21 9:38 ` Michael Walle
2024-03-21 11:55 ` Vaishnav Achath
2024-03-21 12:44 ` Michael Walle
2024-03-21 12:55 ` Andrew Lunn
2024-03-19 6:03 ` Krzysztof Kozlowski
2024-03-19 6:42 ` Ayush Singh
2024-03-19 19:37 ` Conor Dooley
2024-03-22 18:15 ` Ayush Singh
2024-03-22 18:51 ` Andrew Lunn
2024-03-17 19:37 ` [PATCH v4 2/5] spi: Make of_find_spi_controller_by_node() available Ayush Singh
2024-03-19 8:16 ` Markus Elfring
2024-03-17 19:37 ` [PATCH v4 3/5] greybus: Add mikroBUS manifest types Ayush Singh
2024-03-19 8:26 ` Vaishnav Achath
2024-03-17 19:37 ` [PATCH v4 4/5] mikrobus: Add mikroBUS driver Ayush Singh
2024-03-17 19:59 ` Randy Dunlap
2024-03-18 17:34 ` Markus Elfring
2024-03-18 17:58 ` Markus Elfring
2024-03-18 18:41 ` Alex Elder
2024-03-18 18:55 ` Greg Kroah-Hartman
2024-03-18 18:12 ` Markus Elfring
2024-03-19 6:04 ` Krzysztof Kozlowski
2024-03-19 6:47 ` Ayush Singh
2024-03-19 8:00 ` Vaishnav Achath
2024-03-20 7:33 ` Krzysztof Kozlowski
2024-03-19 8:49 ` Vaishnav Achath
2024-03-17 19:37 ` [PATCH v4 5/5] dts: ti: k3-am625-beagleplay: Add mikroBUS Ayush Singh
2024-03-19 5:59 ` Krzysztof Kozlowski
2024-03-19 6:34 ` Ayush Singh
2024-03-20 7:31 ` Krzysztof Kozlowski
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