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Message-ID: <0680EC522D0CC943BC586913CF3768C0041390E05A@dbde02.ent.ti.com>
Date: Fri, 3 Dec 2010 17:03:42 +0530
From: "Datta, Shubhrajyoti" <shubhrajyoti@...com>
To: "Hennerich, Michael" <Michael.Hennerich@...log.com>,
"linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: Drivers <Drivers@...log.com>, "jic23@....ac.uk" <jic23@....ac.uk>,
"device-drivers-devel@...ckfin.uclinux.org"
<device-drivers-devel@...ckfin.uclinux.org>
Subject: RE: [RFC 3/3] IIO: DDS: AD9833 / AD9834 driver
Michel,
Just a thought not a comment. However I think error handling could be dealt later.
> -----Original Message-----
> From: Hennerich, Michael [mailto:Michael.Hennerich@...log.com]
> Sent: Friday, December 03, 2010 4:13 PM
> To: Datta, Shubhrajyoti; linux-iio@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Cc: Drivers; jic23@....ac.uk; device-drivers-devel@...ckfin.uclinux.org
> Subject: RE: [RFC 3/3] IIO: DDS: AD9833 / AD9834 driver
>
> > Datta, Shubhrajyoti wrote on 2010-12-02:
> > > -----Original Message-----
> > > From: linux-iio-owner@...r.kernel.org [mailto:linux-iio-
> > > owner@...r.kernel.org] On Behalf Of michael.hennerich@...log.com
> > > Sent: Thursday, December 02, 2010 5:51 PM
> > > To: linux-iio@...r.kernel.org; linux-kernel@...r.kernel.org
> > > Cc: drivers@...log.com; jic23@....ac.uk; device-drivers-
> > > devel@...ckfin.uclinux.org; Michael Hennerich
> > > Subject: [RFC 3/3] IIO: DDS: AD9833 / AD9834 driver
> > >
> > > From: Michael Hennerich <michael.hennerich@...log.com>
> > >
> > > Example driver using the proposed ABI
> > >
> > > Signed-off-by: Michael Hennerich <michael.hennerich@...log.com>
> > > ---
> > > drivers/staging/iio/dds/Kconfig | 7 +
> > > drivers/staging/iio/dds/Makefile | 1 +
> > > drivers/staging/iio/dds/ad9834.c | 483
> > > ++++++++++++++++++++++++++++++++++++++
> > > drivers/staging/iio/dds/ad9834.h | 112 +++++++++
> > > 4 files changed, 603 insertions(+), 0 deletions(-)
> > > create mode 100644 drivers/staging/iio/dds/ad9834.c
> > > create mode 100644 drivers/staging/iio/dds/ad9834.h
> > >
> > > diff --git a/drivers/staging/iio/dds/Kconfig
> > > b/drivers/staging/iio/dds/Kconfig
> > > index 7969be2..4c9cce3 100644
> > > --- a/drivers/staging/iio/dds/Kconfig
> > > +++ b/drivers/staging/iio/dds/Kconfig
> > > @@ -17,6 +17,13 @@ config AD9832
> > > Say yes here to build support for Analog Devices DDS chip
> > > ad9832 and ad9835, provides direct access via sysfs.
> > >
> > > +config AD9834
> > > + tristate "Analog Devices ad9833/4/ driver"
> > > + depends on SPI
> > > + help
> > > + Say yes here to build support for Analog Devices DDS chip
> > > + AD9833 and AD9834, provides direct access via sysfs.
> > > +
> > > config AD9850
> > > tristate "Analog Devices ad9850/1 driver"
> > > depends on SPI
> > > diff --git a/drivers/staging/iio/dds/Makefile
> > > b/drivers/staging/iio/dds/Makefile
> > > index 6f274ac..1477461 100644
> > > --- a/drivers/staging/iio/dds/Makefile
> > > +++ b/drivers/staging/iio/dds/Makefile
> > > @@ -4,6 +4,7 @@
> > >
> > > obj-$(CONFIG_AD5930) += ad5930.o
> > > obj-$(CONFIG_AD9832) += ad9832.o
> > > +obj-$(CONFIG_AD9834) += ad9834.o
> > > obj-$(CONFIG_AD9850) += ad9850.o
> > > obj-$(CONFIG_AD9852) += ad9852.o
> > > obj-$(CONFIG_AD9910) += ad9910.o
> > > diff --git a/drivers/staging/iio/dds/ad9834.c
> > > b/drivers/staging/iio/dds/ad9834.c
> > > new file mode 100644
> > > index 0000000..eb1fabf
> > > --- /dev/null
> > > +++ b/drivers/staging/iio/dds/ad9834.c
> > > @@ -0,0 +1,483 @@
> > > +/*
> > > + * AD9834 SPI DAC driver
> > > + *
> > > + * Copyright 2010 Analog Devices Inc.
> > > + *
> > > + * Licensed under the GPL-2 or later.
> > > + */
> > > +
> > > +#include <linux/interrupt.h>
> > > +#include <linux/workqueue.h>
> > > +#include <linux/device.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/sysfs.h>
> > > +#include <linux/list.h>
> > > +#include <linux/spi/spi.h>
> > > +#include <linux/regulator/consumer.h>
> > > +#include <linux/err.h>
> > > +#include <asm/div64.h>
> > > +
> > > +#include "../iio.h"
> > > +#include "../sysfs.h"
> > > +#include "dds.h"
> > > +
> > > +#include "ad9834.h"
> > > +
> > > +static unsigned int ad9834_calc_freqreg(unsigned long mclk, unsigned
> > long
> > > fout)
> > > +{
> > > + unsigned long long freqreg = (u64) fout * (u64) (1 <<
> > > AD9834_FREQ_BITS);
> > > + do_div(freqreg, mclk);
> > > + return freqreg;
> > > +}
> > > +
> > > +static int ad9834_write_frequency(struct ad9834_state *st,
> > > + unsigned long addr, unsigned long
> > fout)
> > > +{
> > > + unsigned long regval;
> > > +
> > > + if (fout > (st->mclk / 2))
> > > + return -EINVAL;
> > > +
> > > + regval = ad9834_calc_freqreg(st->mclk, fout);
> > > +
> > > + st->freq_data[0] = cpu_to_be16(addr | (regval &
> > > + RES_MASK(AD9834_FREQ_BITS /
> > 2)));
> > > + st->freq_data[1] = cpu_to_be16(addr | ((regval >>
> > > + (AD9834_FREQ_BITS / 2)) &
> > > + RES_MASK(AD9834_FREQ_BITS /
> > 2)));
> > > +
> > > + return spi_sync(st->spi, &st->freq_msg);;
> > > +}
> > > +
> > > +static int ad9834_write_phase(struct ad9834_state *st,
> > > + unsigned long addr, unsigned long
> > phase)
> > > +{
> > > + if (phase > (1 << AD9834_PHASE_BITS))
> > > + return -EINVAL;
> > > + st->data = cpu_to_be16(addr | phase);
> > > +
> > > + return spi_sync(st->spi, &st->msg);
> > > +}
> > > +
> > > +static ssize_t ad9834_write(struct device *dev,
> > > + struct device_attribute *attr,
> > > + const char *buf,
> > > + size_t len)
> > > +{
> > > + struct iio_dev *dev_info = dev_get_drvdata(dev);
> > > + struct ad9834_state *st = dev_info->dev_data;
> > > + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> > > + int ret;
> > > + long val;
> > > +
> > > + ret = strict_strtol(buf, 10, &val);
> > > + if (ret)
> > > + goto error_ret;
> > Could we do some bounds check.
> The functions called with val as argument from the switch cases below, do
> some bound checking, where necessary.
> It's questionable whether these simple enable switch cases, should return
> with
> error if someone writes something other than 0 or 1.
In that case we could we at least consider ret = strict_strtoul(buf, 10, &val);
> > > +
> > > + mutex_lock(&dev_info->mlock);
> > > + switch (this_attr->address) {
> > > + case AD9834_REG_FREQ0:
> > > + case AD9834_REG_FREQ1:
> > > + ret = ad9834_write_frequency(st, this_attr->address,
> > val);
> > > + break;
> > > + case AD9834_REG_PHASE0:
> > > + case AD9834_REG_PHASE1:
> > > + ret = ad9834_write_phase(st, this_attr->address, val);
> > > + break;
> > > +
> > > + case AD9834_OPBITEN:
> > > + if (st->control & AD9834_MODE) {
> > > + ret = -EINVAL; /* AD9843 reserved mode */
> > > + break;
> > > + }
> > > +
> > > + if (val)
> > > + st->control &= ~AD9834_OPBITEN;
> > > + else
> > > + st->control |= AD9834_OPBITEN;
Here you check for something other than 0 if the user passes -1 then it may go through.
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