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Message-ID: <20161005090443.24576-1-mugunthanvnm@ti.com>
Date: Wed, 5 Oct 2016 14:34:39 +0530
From: Mugunthan V N <mugunthanvnm@...com>
To: <linux-iio@...r.kernel.org>
CC: Tony Lindgren <tony@...mide.com>, Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Russell King <linux@...linux.org.uk>,
Jonathan Cameron <jic23@...nel.org>,
Hartmut Knaack <knaack.h@....de>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Meerwald-Stadler <pmeerw@...erw.net>,
Lee Jones <lee.jones@...aro.org>, Vignesh R <vigneshr@...com>,
"Andrew F . Davis" <afd@...com>, <linux-omap@...r.kernel.org>,
<devicetree@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, Sekhar Nori <nsekhar@...com>,
Peter Ujfalusi <peter.ujfalusi@...com>,
John Syne <john3909@...il.com>,
Mugunthan V N <mugunthanvnm@...com>
Subject: [PATCH v3 0/4] Add DMA support for ti_am335x_adc driver
The ADC has a 64 word depth fifo length which holds the ADC data
till the CPU reads. So when a user program needs a large ADC data
to operate on, then it has to do multiple reads to get its
buffer. Currently if the application asks for 4 samples per
channel with all 8 channels are enabled, kernel can provide only
3 samples per channel when all 8 channels are enabled (logs at
[1]). So with DMA support user can request for large number of
samples at a time (logs at [1]).
Tested the patch on AM437x-gp-evm and AM335x Boneblack with the
patch [2] to enable ADC and pushed a branch for testing [3]
Changes from v2:
* Fixed an issue on handling of error return from dma_request_chan().
Changes from Initial version:
* Changed DMA api from dma_request_slave_channel_compat() to
dma_request_chan()
* Changed variable names to have more clear information as per
comments from Peter.
[1] - http://pastebin.ubuntu.com/23278405/
[2] - http://pastebin.ubuntu.com/23211494/
[3] - git://git.ti.com/~mugunthanvnm/ti-linux-kernel/linux.git iio-dma-v2
Mugunthan V N (4):
mfd: ti_am335x_tscadc: store physical address
drivers: iio: ti_am335x_adc: add dma support
ARM: dts: am33xx: add DMA properties for tscadc
ARM: dts: am4372: add DMA properties for tscadc
arch/arm/boot/dts/am33xx.dtsi | 2 +
arch/arm/boot/dts/am4372.dtsi | 2 +
drivers/iio/adc/ti_am335x_adc.c | 148 ++++++++++++++++++++++++++++++++++-
drivers/mfd/ti_am335x_tscadc.c | 1 +
include/linux/mfd/ti_am335x_tscadc.h | 8 ++
5 files changed, 158 insertions(+), 3 deletions(-)
--
2.10.0.372.g6fe1b14
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