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@xxxxxxxxxxxxxxx> >>> Signed-off-by: Vaishnav M A <vaishnav@xxxxxxxxxxxxxxx> >>> Signed-off-by: Ayush Singh <ayushdevel1325@xxxxxxxxx> >>> --- >>> .../connector/mikrobus-connector.yaml | 113 ++++++++++++++++++ >> See also >> https://lore.kernel.org/r/YmFo+EntwxIsco%2Ft@xxxxxxxxxxxxxxxxxx/ >> >> 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 _______________________________________________ greybus-dev mailing list -- greybus-dev@xxxxxxxxxxxxxxxx To unsubscribe send an email to greybus-dev-leave@xxxxxxxxxxxxxxxx
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