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From: Stefan Wahren <stefan.wahren@i2se.com>
To: kernel@martin.sperl.org, Mark Brown <broonie@kernel.org>,
	Eric Anholt <eric@anholt.net>,
	Hubert Denkmair <h.denkmair@intence.de>,
	linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V2 9/9] spi: bcm2835aux: make the polling duration limits configurable
Date: Mon, 25 Mar 2019 10:44:19 +0100	[thread overview]
Message-ID: <4da737f4-acf2-c70d-59cd-0efdf2ec21d4@i2se.com> (raw)
In-Reply-To: <20190324175002.28969-10-kernel@martin.sperl.org>

Hi Martin,

Am 24.03.19 um 18:50 schrieb kernel@martin.sperl.org:
> From: Martin Sperl <kernel@martin.sperl.org>
>
> Under some circumstances the default 30 us polling limit is not optimal
> and may lead to long delays because we are waiting on an interrupt.
> with this patch we have the possibility to influence this policy.
>
> So make this limit (in us) configurable via a module parameters
> (but also modifyable via /sys/modules/...)
>
> Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
>
> ---
> Changelog:
>   V1 -> V2: remove the dependency on a different patchset focused on
> 	    making cs_change delay configurable
>
> ---
>  drivers/spi/spi-bcm2835aux.c | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
> index d2b58060b333..df065108122b 100644
> --- a/drivers/spi/spi-bcm2835aux.c
> +++ b/drivers/spi/spi-bcm2835aux.c
> @@ -37,6 +37,12 @@
>  #include <linux/spi/spi.h>
>  #include <linux/spinlock.h>
>
> +/* define polling limits */
> +unsigned int polling_limit_us = 30;
> +module_param(polling_limit_us, uint, 0664);
> +MODULE_PARM_DESC(polling_limit_us,
> +		 "time in us to run a transfer in polling mode\n");
> +
could you please document the case polling_limit_us = 0 ?

WARNING: multiple messages have this Message-ID (diff)
From: Stefan Wahren <stefan.wahren@i2se.com>
To: kernel@martin.sperl.org, Mark Brown <broonie@kernel.org>,
	Eric Anholt <eric@anholt.net>,
	Hubert Denkmair <h.denkmair@intence.de>,
	linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V2 9/9] spi: bcm2835aux: make the polling duration limits configurable
Date: Mon, 25 Mar 2019 10:44:19 +0100	[thread overview]
Message-ID: <4da737f4-acf2-c70d-59cd-0efdf2ec21d4@i2se.com> (raw)
In-Reply-To: <20190324175002.28969-10-kernel@martin.sperl.org>

Hi Martin,

Am 24.03.19 um 18:50 schrieb kernel@martin.sperl.org:
> From: Martin Sperl <kernel@martin.sperl.org>
>
> Under some circumstances the default 30 us polling limit is not optimal
> and may lead to long delays because we are waiting on an interrupt.
> with this patch we have the possibility to influence this policy.
>
> So make this limit (in us) configurable via a module parameters
> (but also modifyable via /sys/modules/...)
>
> Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
>
> ---
> Changelog:
>   V1 -> V2: remove the dependency on a different patchset focused on
> 	    making cs_change delay configurable
>
> ---
>  drivers/spi/spi-bcm2835aux.c | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
> index d2b58060b333..df065108122b 100644
> --- a/drivers/spi/spi-bcm2835aux.c
> +++ b/drivers/spi/spi-bcm2835aux.c
> @@ -37,6 +37,12 @@
>  #include <linux/spi/spi.h>
>  #include <linux/spinlock.h>
>
> +/* define polling limits */
> +unsigned int polling_limit_us = 30;
> +module_param(polling_limit_us, uint, 0664);
> +MODULE_PARM_DESC(polling_limit_us,
> +		 "time in us to run a transfer in polling mode\n");
> +
could you please document the case polling_limit_us = 0 ?

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  reply	other threads:[~2019-03-25  9:44 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-24 17:49 [PATCH V2 0/9] spi: bcm2835aux: bug fixes and improvements kernel
2019-03-24 17:49 ` kernel
2019-03-24 17:49 ` [PATCH V2 3/9] spi: bcm2835aux: use BCM2835_AUX_SPI_STAT_RX_LVL kernel
2019-03-24 17:49   ` kernel
2019-03-25  9:52   ` Stefan Wahren
2019-03-25  9:52     ` Stefan Wahren
2019-03-24 17:49 ` [PATCH V2 6/9] spi: bcm2835aux: warn in dmesg that native cs is not really supported kernel
2019-03-24 17:49   ` kernel
2019-03-25 10:28   ` Stefan Wahren
2019-03-25 10:28     ` Stefan Wahren
     [not found] ` <20190324175002.28969-1-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2019-03-24 17:49   ` [PATCH V2 1/9] spi: bcm2835aux: unifying code between polling and interrupt driven code kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:49     ` kernel
2019-03-24 17:49   ` [PATCH V2 2/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:49     ` kernel
2019-03-24 17:49   ` [PATCH V2 4/9] spi: bcm2835aux: remove dead code kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:49     ` kernel
2019-03-24 17:49   ` [PATCH V2 5/9] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:49     ` kernel
2019-03-24 17:50   ` [PATCH V2 7/9] spi: bcm2835aux: setup gpio-cs to output and correct level during setup kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:50     ` kernel
2019-03-24 17:50   ` [PATCH V2 8/9] spi: bcm2835aux: add driver stats to debugfs kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:50     ` kernel
2019-03-25  9:28     ` Stefan Wahren
2019-03-25  9:28       ` Stefan Wahren
2019-03-25  9:52       ` kernel
2019-03-25 10:06         ` Stefan Wahren
2019-03-25 10:11           ` kernel
2019-03-25 10:45             ` Stefan Wahren
2019-03-24 17:50   ` [PATCH V2 9/9] spi: bcm2835aux: make the polling duration limits configurable kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:50     ` kernel
2019-03-25  9:44     ` Stefan Wahren [this message]
2019-03-25  9:44       ` Stefan Wahren
2019-03-25  9:49       ` kernel
2019-03-25  9:49         ` kernel
2019-03-25  9:59         ` Stefan Wahren
2019-03-25  9:59           ` Stefan Wahren

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