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From: Mark Brown <broonie@kernel.org>
To: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Serge Semin <fancer.lancer@gmail.com>,
	Gregory Clement <gregory.clement@bootlin.com>,
	Charles Keepax <ckeepax@opensource.cirrus.com>,
	Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>,
	Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>,
	Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Paul Burton <paulburton@kernel.org>,
	Ralf Baechle <ralf@linux-mips.org>, Arnd Bergmann <arnd@arndb.de>,
	Allison Randal <allison@lohutok.net>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Gareth Williams <gareth.williams.jx@renesas.com>,
	Rob Herring <robh+dt@kernel.org>,
	linux-mips@vger.kernel.org,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Phil Edworthy <phil.edworthy@renesas.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Alexios Zavras <alexios.zavras@intel.com>,
	Thor Thayer <thor.thayer@linux.intel.com>,
	"wuxu.wu" <wuxu.wu@huawei.com>,
	Xinwei Kong <kong.kongxinwei@hisilicon.com>,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	linux-spi <linux-spi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/17] spi: dw: Fix native CS being unset
Date: Thu, 14 May 2020 15:35:37 +0100	[thread overview]
Message-ID: <20200514143537.GH5127@sirena.org.uk> (raw)
In-Reply-To: <20200514115558.e6cqnuxqyqkysfn7@mobilestation>

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On Thu, May 14, 2020 at 02:55:58PM +0300, Serge Semin wrote:
> On Thu, May 14, 2020 at 10:31:13AM +0200, Linus Walleij wrote:

> > We had some related discussion what to do with this case
> > when a controller can support active high CS if and only if
> > it is using a GPIO instead of the native CS. We didn't really
> > figure it out, I suppose ideally we should use two flags in the
> > master but that exercise is for another day.

> Even though it might be painful, but as I see it the best way to generically fix
> this problem would be to change the controller->set_cs() callback
> semantics. SPI core should pass a CS activation flag to the set_cs()
> callback instead of the CS pin logical level (just propagate the enable argument
> passed to the spi_set_cs() SPI core method). So if an SPI controller supports
> the Active-high native CS, during the set_cs() callback invocation it would
> analyze the spi_device flags state to figure out whether the slave needs the

The idea with set_cs() is to support controllers that allow the chip
select to be directly managed.  If the controller is interpreting or
automatically managing chip select at all then set_cs() is not likely to
be a good fit, if the controller does support unfiltered management then
anything else is going to result in there being a bunch of duplicate
code between drivers.

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  parent reply	other threads:[~2020-05-14 14:35 UTC|newest]

Thread overview: 106+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-08 13:29 [PATCH 00/17] spi: dw: Add generic DW DMA controller support Serge Semin
2020-05-08 13:29 ` [PATCH 01/17] dt-bindings: spi: Convert DW SPI binding to DT schema Serge Semin
2020-05-08 19:39   ` Andy Shevchenko
2020-05-12 20:28     ` Serge Semin
2020-05-12 20:35       ` Andy Shevchenko
2020-05-08 13:29 ` [PATCH 02/17] dt-bindings: spi: dw: Add DMA properties bindings Serge Semin
2020-05-08 13:29 ` [PATCH 04/17] spi: dw: Cleanup generic DW DMA code namings Serge Semin
2020-05-08 19:43   ` Andy Shevchenko
2020-05-12 21:26     ` Serge Semin
2020-05-12 21:37       ` Andy Shevchenko
2020-05-08 13:29 ` [PATCH 06/17] spi: dw: Add DW SPI DMA/PCI/MMIO dependency on DW SPI core Serge Semin
2020-05-08 13:29 ` [PATCH 08/17] spi: dw: Clear DMAC register when done or stopped Serge Semin
2020-05-08 17:31   ` Mark Brown
2020-05-13 11:56     ` Serge Semin
2020-05-08 13:29 ` [PATCH 09/17] spi: dw: Enable interrupts in accordance with DMA xfer mode Serge Semin
2020-05-08 13:29 ` [PATCH 10/17] spi: dw: Parameterize the DMA Rx/Tx burst length Serge Semin
2020-05-08 13:29 ` [PATCH 12/17] spi: dw: Fix dma_slave_config used partly uninitialized Serge Semin
2020-05-08 19:20   ` Andy Shevchenko
2020-05-08 13:29 ` [PATCH 13/17] spi: dw: Initialize paddr in DW SPI MMIO private data Serge Semin
2020-05-08 19:21   ` Andy Shevchenko
2020-05-13 12:30     ` Serge Semin
2020-05-08 13:33 ` [PATCH 00/17] spi: dw: Add generic DW DMA controller support Mark Brown
2020-05-12 20:07   ` Serge Semin
2020-05-13 10:23     ` Mark Brown
2020-05-13 11:04       ` Serge Semin
2020-05-13 11:21         ` Mark Brown
2020-05-13 11:42           ` Serge Semin
     [not found] ` <20200508132943.9826-8-Sergey.Semin@baikalelectronics.ru>
2020-05-08 17:30   ` [PATCH 07/17] spi: dw: Add Tx/Rx finish wait methods to DMA Mark Brown
     [not found]     ` <20200513113555.mjivjk374giopnea@mobilestation>
2020-05-13 11:36       ` Mark Brown
2020-05-08 17:36 ` [PATCH 00/17] spi: dw: Add generic DW DMA controller support Mark Brown
2020-05-08 19:16   ` Andy Shevchenko
2020-05-12 20:34     ` Serge Semin
2020-05-12 20:30   ` Serge Semin
     [not found] ` <20200508132943.9826-15-Sergey.Semin@baikalelectronics.ru>
2020-05-08 19:23   ` [PATCH 14/17] spi: dw: Add DMA support to the DW SPI MMIO driver Andy Shevchenko
     [not found] ` <20200508132943.9826-17-Sergey.Semin@baikalelectronics.ru>
2020-05-08 19:27   ` [PATCH 16/17] spi: dw: Fix Rx-only DMA transfers Andy Shevchenko
     [not found] ` <20200508132943.9826-18-Sergey.Semin@baikalelectronics.ru>
2020-05-08 19:30   ` [PATCH 17/17] spi: dw: Use regset32 DebugFS method to create a registers file Andy Shevchenko
     [not found]     ` <20200513124422.z6ctlmvipwer45q4@mobilestation>
2020-05-13 14:41       ` Andy Shevchenko
2020-05-08 19:33 ` [PATCH 00/17] spi: dw: Add generic DW DMA controller support Andy Shevchenko
     [not found] ` <20200508132943.9826-12-Sergey.Semin@baikalelectronics.ru>
2020-05-08 19:39   ` [PATCH 11/17] spi: dw: Fix native CS being unset Linus Walleij
     [not found]     ` <20200513001347.dyt357erev7vzy3l@mobilestation>
2020-05-14  8:31       ` Linus Walleij
     [not found]         ` <20200514115558.e6cqnuxqyqkysfn7@mobilestation>
2020-05-14 12:22           ` Andy Shevchenko
2020-05-14 13:03             ` Mark Brown
2020-05-14 14:35           ` Mark Brown [this message]
     [not found] ` <20200508132943.9826-4-Sergey.Semin@baikalelectronics.ru>
2020-05-08 19:41   ` [PATCH 03/17] spi: dw: Split up the generic DMA code and Intel MID driver Andy Shevchenko
     [not found] ` <20200508132943.9826-6-Sergey.Semin@baikalelectronics.ru>
2020-05-08 19:44   ` [PATCH 05/17] spi: dw: Discard static DW DMA slave structures Andy Shevchenko
2020-05-15 10:47 ` [PATCH v2 00/19] spi: dw: Add generic DW DMA controller support Serge Semin
2020-05-15 10:47   ` [PATCH v2 01/19] dt-bindings: spi: dw: Add Tx/Rx DMA properties Serge Semin
2020-05-15 11:51     ` Andy Shevchenko
2020-05-15 12:27       ` Mark Brown
2020-05-15 15:43         ` Serge Semin
2020-05-15 10:47   ` [PATCH v2 03/19] spi: dw: Clear DMAC register when done or stopped Serge Semin
2020-05-15 12:01     ` Andy Shevchenko
2020-05-15 16:42     ` Mark Brown
2020-05-15 17:21       ` Serge Semin
2020-05-15 10:47   ` [PATCH v2 05/19] spi: dw: Enable interrupts in accordance with DMA xfer mode Serge Semin
2020-05-15 12:27     ` Andy Shevchenko
2020-05-16 14:06       ` Serge Semin
2020-05-15 10:47   ` [PATCH v2 09/19] spi: dw: Parameterize the DMA Rx/Tx burst length Serge Semin
2020-05-15 14:01     ` Andy Shevchenko
     [not found]       ` <20200516143353.hw6nny5hbwgiyxfw@mobilestation>
2020-05-18 11:01         ` Andy Shevchenko
2020-05-18 12:41           ` Serge Semin
2020-05-15 10:47   ` [PATCH v2 10/19] spi: dw: Use DMA max burst to set the request thresholds Serge Semin
2020-05-15 14:38     ` Andy Shevchenko
     [not found]       ` <20200516200133.wmaqnfjbr7234fzo@mobilestation>
2020-05-18 11:03         ` Andy Shevchenko
2020-05-18 12:43           ` Mark Brown
2020-05-18 12:52           ` Serge Semin
2020-05-18 13:25             ` Andy Shevchenko
2020-05-18 13:43               ` Serge Semin
2020-05-18 14:48                 ` Andy Shevchenko
2020-05-18 14:59                   ` Serge Semin
2020-05-15 10:47   ` [PATCH v2 11/19] spi: dw: Initialize paddr in DW SPI MMIO private data Serge Semin
2020-05-15 14:39     ` Andy Shevchenko
2020-05-15 10:47   ` [PATCH v2 14/19] spi: dw: Remove DW DMA code dependency from DW_DMAC_PCI Serge Semin
2020-05-15 15:02     ` Andy Shevchenko
2020-05-15 10:47   ` [PATCH v2 15/19] spi: dw: Add DW SPI DMA/PCI/MMIO dependency on the DW SPI core Serge Semin
2020-05-15 15:03     ` Andy Shevchenko
2020-05-15 10:47   ` [PATCH v2 17/19] spi: dw: Add DMA support to the DW SPI MMIO driver Serge Semin
2020-05-15 15:08     ` Andy Shevchenko
2020-05-15 10:47   ` [PATCH v2 19/19] dt-bindings: spi: Convert DW SPI binding to DT schema Serge Semin
2020-05-16 20:59     ` Serge Semin
2020-05-15 11:49   ` [PATCH v2 00/19] spi: dw: Add generic DW DMA controller support Andy Shevchenko
2020-05-15 15:30     ` Serge Semin
     [not found]   ` <20200515104758.6934-3-Sergey.Semin@baikalelectronics.ru>
2020-05-15 12:01     ` [PATCH v2 02/19] spi: dw: Add Tx/Rx finish wait methods to the MID DMA Andy Shevchenko
2020-05-15 12:18       ` Mark Brown
2020-05-15 12:37         ` Andy Shevchenko
2020-05-15 12:41           ` Mark Brown
     [not found]             ` <20200515200250.zjsv5uaftwqcnwud@mobilestation>
2020-05-18 10:51               ` Mark Brown
     [not found]                 ` <20200518110453.w3ko5a5yzwyr73ir@mobilestation>
2020-05-18 11:11                   ` Mark Brown
     [not found]       ` <20200515194058.pmpd4wa7lw2dle3g@mobilestation>
2020-05-18 10:55         ` Andy Shevchenko
     [not found]   ` <20200515104758.6934-5-Sergey.Semin@baikalelectronics.ru>
2020-05-15 12:05     ` [PATCH v2 04/19] spi: dw: Fix native CS being unset Andy Shevchenko
     [not found]   ` <20200515104758.6934-7-Sergey.Semin@baikalelectronics.ru>
2020-05-15 12:34     ` [PATCH v2 06/19] spi: dw: Discard static DW DMA slave structures Andy Shevchenko
     [not found]       ` <20200516142030.kburieaxjg4n7c42@mobilestation>
2020-05-18 11:00         ` Andy Shevchenko
2020-05-18 11:38           ` Andy Shevchenko
     [not found]             ` <20200518123242.xoosc4pcj7heo4he@mobilestation>
2020-05-18 13:22               ` Andy Shevchenko
     [not found]   ` <20200515104758.6934-8-Sergey.Semin@baikalelectronics.ru>
2020-05-15 12:38     ` [PATCH v2 07/19] spi: dw: Discard unused void priv pointer Andy Shevchenko
     [not found]   ` <20200515104758.6934-9-Sergey.Semin@baikalelectronics.ru>
2020-05-15 13:03     ` [PATCH v2 08/19] spi: dw: Discard dma_width member of the dw_spi structure Andy Shevchenko
     [not found]       ` <20200515130559.psq2zwfhovt6rzhl@mobilestation>
2020-05-15 13:49         ` Andy Shevchenko
     [not found]           ` <20200515141627.pqdaic6wksatusl6@mobilestation>
2020-05-15 15:00             ` Andy Shevchenko
     [not found]   ` <20200515104758.6934-13-Sergey.Semin@baikalelectronics.ru>
2020-05-15 14:40     ` [PATCH v2 12/19] spi: dw: Fix Rx-only DMA transfers Andy Shevchenko
2020-05-15 16:55       ` Mark Brown
     [not found]   ` <20200515104758.6934-14-Sergey.Semin@baikalelectronics.ru>
2020-05-15 14:51     ` [PATCH v2 13/19] spi: dw: Move Non-DMA code to the DW PCIe-SPI driver Andy Shevchenko
     [not found]       ` <20200516201724.7q5uhxmzpr6xjooj@mobilestation>
     [not found]         ` <20200518125850.jnhaqlr2ticu3ivs@mobilestation>
2020-05-18 13:00           ` Mark Brown
     [not found]   ` <20200515104758.6934-19-Sergey.Semin@baikalelectronics.ru>
2020-05-15 15:10     ` [PATCH v2 18/19] spi: dw: Use regset32 DebugFS method to create regdump file Andy Shevchenko
     [not found]       ` <20200516204634.td52orxfnh7iewg6@mobilestation>
2020-05-18 11:18         ` Andy Shevchenko
     [not found]           ` <20200518140825.jnkfpybxnwq7fx2m@mobilestation>
2020-05-18 15:06             ` Andy Shevchenko
2020-05-15 18:21   ` [PATCH v2 00/19] spi: dw: Add generic DW DMA controller support Mark Brown

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