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From: "B. Niedermayr" <benedikt.niedermayr@siemens.com>
To: <linux-omap@vger.kernel.org>, <devicetree@vger.kernel.org>
Cc: <rogerq@kernel.org>, <tony@atomide.com>,
	<krzysztof.kozlowski@linaro.org>, <robh+dt@kernel.org>
Subject: [PATCH v4 0/3] omap-gpmc wait pin additions
Date: Thu, 15 Sep 2022 11:13:30 +0200	[thread overview]
Message-ID: <20220915091333.2425306-1-benedikt.niedermayr@siemens.com> (raw)

From: Benedikt Niedermayr <benedikt.niedermayr@siemens.com>

Currently it is not possible to configure the WAIT0PINPOLARITY and 
WAIT1PINPOLARITY bits of the GPMC_CONFIG register directly via 
device tree properties.

It is also not possible to use the same wait-pin for different 
cs-regions.

While the current implementation may fullfill most usecases, it may not
be sufficient for more complex setups (e.g. FPGA/ASIC interfaces), where 
more complex interfacing options where possible.

For example interfacing an ASIC which offers multiple cs-regions but
only one waitpin the current driver and dt-bindings are not sufficient.

While using the same waitpin for different cs-regions worked for older
kernels (4.14) the omap-gpmc.c driver refused to probe (-EBUSY) with
newer kernels (>5.10).

Changes since v1: 
  * Rebase against recent 6.0.0-rc3 kernel, but the maintainers list
    stays the same!
  * Updated eMail recipients list
Changes since v2:
  * Remove the gpmc register configuration out of the gpiochip
    callbacks. In this case the memory interface configuration
    is not done via gpio bindings.
  * Some minor code fixes
  * Changed git commit descriptions
Change since v3:
  * Use a uint32 dt-property instean a boolean one
  * If the dt-property is not set, then don't touch the
    GPMC_CONFIG register
  * Changed git commit descriptions


Benedikt Niedermayr (3):
  memory: omap-gpmc: allow shared wait pins
  memory: omap-gpmc: add support for wait pin polarity
  dt-bindings: memory-controllers: gpmc-child: add wait-pin polarity

 .../memory-controllers/ti,gpmc-child.yaml     |  7 +++++
 drivers/memory/omap-gpmc.c                    | 30 +++++++++++++++++--
 include/linux/platform_data/gpmc-omap.h       |  6 ++++
 3 files changed, 41 insertions(+), 2 deletions(-)

-- 
2.34.1


             reply	other threads:[~2022-09-15  9:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-15  9:13 B. Niedermayr [this message]
2022-09-15  9:13 ` [PATCH v4 1/3] memory: omap-gpmc: allow shared wait pins B. Niedermayr
2022-09-16  8:50   ` Roger Quadros
2022-09-15  9:13 ` [PATCH v4 2/3] memory: omap-gpmc: add support for wait pin polarity B. Niedermayr
2022-09-16  8:46   ` Roger Quadros
2022-09-16  8:55   ` Roger Quadros
2022-09-16  9:17     ` Niedermayr, BENEDIKT
2022-09-15  9:13 ` [PATCH v4 3/3] dt-bindings: memory-controllers: gpmc-child: add wait-pin polarity B. Niedermayr

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