From: William Zhang <william.zhang@broadcom.com>
To: Mark Brown <broonie@kernel.org>
Cc: Linux SPI List <linux-spi@vger.kernel.org>,
Broadcom Kernel List <bcm-kernel-feedback-list@broadcom.com>,
anand.gore@broadcom.com, tomer.yacoby@broadcom.com,
dan.beygelman@broadcom.com, joel.peshkin@broadcom.com,
f.fainelli@gmail.com, jonas.gorski@gmail.com,
kursad.oney@broadcom.com, dregan@mail.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 07/16] spi: bcm63xx-hsspi: Add polling mode support
Date: Fri, 6 Jan 2023 19:35:59 -0800 [thread overview]
Message-ID: <ec84b84b-41be-32ad-2e76-afac59a621d0@broadcom.com> (raw)
In-Reply-To: <Y7iW38Fsj0nIewDm@sirena.org.uk>
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On 01/06/2023 01:47 PM, Mark Brown wrote:
> On Fri, Jan 06, 2023 at 12:07:59PM -0800, William Zhang wrote:
>
>> Polling mode provides better throughput in general by avoiding the
>> interrupt overhead as the maximum data size one interrupt can handle is
>> only 512 bytes.
>
>> When interrupt is not defined in the HSSPI dts node, driver switches to
>> polling mode for controller SPI message processing. Also add driver
>> banner message when the driver is loaded successfully.
>
> This should not be something the user selects via the DT, if the polling
> mode is better then the driver should just use it regardless of there
> being an interrupt wired up. Generally there's some point at which the
> benefits of polling become minimal (and the costs more impactful) but if
> the DMA setup is as bad as it sounds then the driver should just ignore
> the interrupt.
>
I agree but this is more for backward compatibility as the original
driver uses interrupt to work with MIPS based SoC and I do not want to
change that behavior. For newer devices I added, they work in polling
mode by default with the dts I supplied. IMHO it is also good to have
this fallback option to use interrupt in case user is sensitive to cpu
usage.
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next prev parent reply other threads:[~2023-01-07 3:36 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-06 20:07 [PATCH 00/16] spi: bcm63xx-hsspi: driver and doc updates William Zhang
2023-01-06 20:07 ` [PATCH 01/16] dt-bindings: spi: Convert bcm63xx-hsspi bindings to json-schema William Zhang
2023-01-07 15:18 ` Rob Herring
2023-01-07 15:32 ` Krzysztof Kozlowski
2023-01-09 7:52 ` William Zhang
2023-01-09 8:48 ` Krzysztof Kozlowski
2023-01-06 20:07 ` [PATCH 02/16] dt-bindings: spi: Add bcmbca-hsspi controller support William Zhang
2023-01-08 14:51 ` Krzysztof Kozlowski
2023-01-09 8:27 ` William Zhang
2023-01-09 8:56 ` Krzysztof Kozlowski
2023-01-09 19:13 ` William Zhang
2023-01-10 8:40 ` Krzysztof Kozlowski
2023-01-10 22:18 ` Florian Fainelli
2023-01-11 1:08 ` William Zhang
2023-01-11 9:02 ` Krzysztof Kozlowski
2023-01-11 18:04 ` William Zhang
2023-01-11 18:12 ` Krzysztof Kozlowski
2023-01-11 18:44 ` William Zhang
2023-01-12 8:21 ` Krzysztof Kozlowski
2023-01-12 19:50 ` William Zhang
2023-01-13 7:41 ` Krzysztof Kozlowski
2023-01-14 3:17 ` William Zhang
2023-01-15 14:31 ` Krzysztof Kozlowski
2023-01-11 0:59 ` William Zhang
2023-01-11 9:01 ` Krzysztof Kozlowski
2023-01-06 20:07 ` [PATCH 03/16] dt-bindings: spi: Add spi peripheral specific property William Zhang
2023-01-06 21:14 ` Mark Brown
2023-01-07 3:27 ` William Zhang
2023-01-07 15:38 ` Rob Herring
2023-01-09 8:06 ` William Zhang
2023-01-09 19:19 ` Mark Brown
2023-01-09 20:18 ` William Zhang
2023-01-10 22:01 ` Mark Brown
2023-01-11 19:48 ` William Zhang
2023-01-08 14:52 ` Krzysztof Kozlowski
2023-01-09 8:27 ` William Zhang
2023-01-06 20:07 ` [PATCH 04/16] ARM: dts: broadcom: bcmbca: Add spi controller node William Zhang
2023-01-06 20:07 ` [PATCH 05/16] arm64: " William Zhang
2023-01-06 20:07 ` [PATCH 06/16] spi: bcm63xx-hsspi: Endianness fix for ARM based SoC William Zhang
2023-01-07 7:44 ` kernel test robot
2023-01-07 21:21 ` kernel test robot
2023-01-07 21:52 ` kernel test robot
2023-01-07 23:23 ` kernel test robot
2023-01-11 6:33 ` kernel test robot
2023-01-06 20:07 ` [PATCH 07/16] spi: bcm63xx-hsspi: Add polling mode support William Zhang
2023-01-06 21:47 ` Mark Brown
2023-01-07 3:35 ` William Zhang [this message]
2023-01-09 19:06 ` Mark Brown
2023-01-09 20:10 ` William Zhang
2023-01-10 22:49 ` Mark Brown
2023-01-11 20:13 ` William Zhang
2023-01-11 22:41 ` Mark Brown
2023-01-11 22:57 ` William Zhang
2023-01-06 20:08 ` [PATCH 08/16] spi: bcm63xx-hsspi: Handle cs_change correctly William Zhang
2023-01-06 20:08 ` [PATCH 09/16] spi: bcm63xx-hsspi: Fix multi-bit mode setting William Zhang
2023-01-06 20:08 ` [PATCH 10/16] spi: bcm63xx-hsspi: Make dummy cs workaround as an option William Zhang
2023-01-12 18:08 ` Mark Brown
2023-01-18 23:09 ` William Zhang
2023-01-19 13:09 ` Mark Brown
2023-01-06 20:08 ` [PATCH 11/16] spi: bcm63xx-hsspi: Add prepend feature support William Zhang
2023-01-06 22:00 ` Mark Brown
2023-01-07 3:52 ` William Zhang
2023-01-09 19:31 ` Mark Brown
2023-01-09 20:43 ` William Zhang
2023-01-10 21:18 ` Mark Brown
2023-01-11 19:42 ` William Zhang
2023-01-12 16:57 ` Mark Brown
2023-01-06 20:08 ` [PATCH 12/16] spi: bcm63xx-hsspi: Add clock gate disable option support William Zhang
2023-01-06 20:08 ` [PATCH 13/16] spi: spi-mem: Allow controller supporting mem_ops without exec_op William Zhang
2023-01-06 20:08 ` [PATCH 14/16] spi: bcm63xx-hsspi: prepend: Disable spi mem dual io read op support William Zhang
2023-01-06 22:07 ` Mark Brown
2023-01-07 3:57 ` William Zhang
2023-01-06 20:08 ` [PATCH 15/16] spi: bcmbca-hsspi: Add driver for newer HSSPI controller William Zhang
2023-01-07 22:02 ` kernel test robot
2023-01-08 2:25 ` kernel test robot
2023-01-06 20:08 ` [PATCH 16/16] MAINTAINERS: Add entry for Broadcom Broadband SoC HS SPI drivers William Zhang
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