Re: [PATCH v2 03/12] bus: stm32-fmc2-ebi: add STM32 FMC2 EBI controller driver

From: Christophe Kerello
Date: Fri Apr 17 2020 - 11:30:11 EST




On 4/16/20 9:53 PM, Boris Brezillon wrote:
On Wed, 15 Apr 2020 17:57:27 +0200
Christophe Kerello <christophe.kerello@xxxxxx> wrote:

The driver adds the support for the STMicroelectronics FMC2 EBI controller
found on STM32MP SOCs.

Signed-off-by: Christophe Kerello <christophe.kerello@xxxxxx>
Tested-by: Marek Vasut <marex@xxxxxxx>
---
Changes in v2:
- call 2 APIs to manage FMC2 enable/disable instead of ops
- call 2 APIs to manage FMC2 NWAIT shared signal instead of ops

drivers/bus/Kconfig | 11 +
drivers/bus/Makefile | 1 +
drivers/bus/stm32-fmc2-ebi.c | 1091 ++++++++++++++++++++++++++++++++++++++++++

Hm, I see that other memory bus controller drivers are placed under
drivers/memory/, any reason for choosing drivers/bus/? If that's where
we want to have all generic memory bus controllers to live it might be
worth moving existing drivers to the drivers/bus/ directory at some
point.


Hi Boris,

I see this controller as an external bus interface as we are able to attach different devices on it, like a PSRAM, an ethernet controller, a FPGA, a LCD display, ...

When I had a look at bus/Kconfig file, I have found similar drivers (like IMX_WEIM or QCOM_EBI2 drivers). These drivers are able to connect devices like NAND Flash, SRAM, ethernet adapters, FPGAs and LCD displays as it is written in the Kconfig file.

But, after checking memory/Kconfig file, it is also possible to find similar drivers (like ATMEL_EBI driver that is inspired by the WEIM bus driver).

So, I will follow the recommendation and I will move it to drivers/memory folder if it is the place where this driver should be.

Regards,
Christophe Kerello.