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Message-ID: <507C1D1C.2030607@metafoo.de>
Date: Mon, 15 Oct 2012 16:26:36 +0200
From: Lars-Peter Clausen <lars@...afoo.de>
To: Lars Poeschel <larsi@....tu-dresden.de>
CC: sameo@...ux.intel.com, linux-kernel@...r.kernel.org,
jic23@....ac.uk, khali@...ux-fr.org, ben-linux@...ff.org,
w.sang@...gutronix.de, grant.likely@...retlab.ca,
linus.walleij@...aro.org, Lars Poeschel <poeschel@...onage.de>,
"linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>
Subject: Re: [PATCH v2 4/4] iio: adc: add viperboard adc driver
Added linux-iio@...r.kernel.org to Cc.
On 10/12/2012 04:34 PM, Lars Poeschel wrote:
> From: Lars Poeschel <poeschel@...onage.de>
>
> This adds the mfd cell to use the adc part of the Nano River Technologies
> viperboard.
>
> Signed-off-by: Lars Poeschel <poeschel@...onage.de>
Looks good in general, just some minor code style issues.
> ---
> drivers/iio/adc/Kconfig | 7 ++
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/viperboard_adc.c | 185 ++++++++++++++++++++++++++++++++++++++
> drivers/mfd/viperboard.c | 3 +
> 4 files changed, 196 insertions(+)
> create mode 100644 drivers/iio/adc/viperboard_adc.c
>
[...]
> diff --git a/drivers/iio/adc/viperboard_adc.c b/drivers/iio/adc/viperboard_adc.c
> new file mode 100644
> index 0000000..8ae6634
> --- /dev/null
> +++ b/drivers/iio/adc/viperboard_adc.c
> @@ -0,0 +1,185 @@
> +/*
> + * Nano River Technologies viperboard iio ADC driver
> + *
> + * (C) 2012 by Lemonage GmbH
> + * Author: Lars Poeschel <poeschel@...onage.de>
> + * All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/usb.h>
> +#include <linux/iio/iio.h>
> +
> +#include <linux/mfd/viperboard.h>
> +
> +#define VPRBRD_ADC_CMD_GET 0x00
> +
> +struct __packed vprbrd_adc_msg {
> + u8 cmd;
> + u8 chan;
> + u8 val;
> +};
put the __packed between } and ;
> +
> +struct vprbrd_adc {
> + struct vprbrd *vb;
> +};
> +
> +#define VPRBRD_ADC_CHANNEL(_index) { \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .channel = _index, \
> + .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT, \
It would be good if you could also report the channel scale.
> + .scan_index = _index, \
> + .scan_type.sign = 'u', \
> + .scan_type.realbits = 8, \
> + .scan_type.storagebits = 8, \
Usually this is written as
.scan_type = {
.sign = 'u',
....
},
> +}
> +
> +static struct iio_chan_spec vprbrd_adc_iio_channels[] = {
const
> + VPRBRD_ADC_CHANNEL(0),
> + VPRBRD_ADC_CHANNEL(1),
> + VPRBRD_ADC_CHANNEL(2),
> + VPRBRD_ADC_CHANNEL(3),
> +};
> +
> +static int vprbrd_iio_read_raw(struct iio_dev *iio_dev,
> + struct iio_chan_spec const *chan,
> + int *val,
> + int *val2,
> + long mask)
'mask' used to be a mask and that's why it is still called 'mask' in older
drivers. For new drivers we should use 'info'.
> +{
> + int ret, error = 0;
> + struct vprbrd_adc *adc = iio_priv(iio_dev);
> + struct vprbrd *vb = adc->vb;
> + struct vprbrd_adc_msg *admsg = (struct vprbrd_adc_msg *)vb->buf;
> +
> + if (mask == IIO_CHAN_INFO_RAW) {
> +
Use switch instead of if. Otherwise you'd end up with if(mask == ...) else
if(mask == ...) else if (mask == ...) if you add support for more channel
attributes.
> + mutex_lock(&vb->lock);
> +
> + admsg->cmd = VPRBRD_ADC_CMD_GET;
> + admsg->chan = chan->scan_index;
> + admsg->val = 0x00;
> +
> + ret = usb_control_msg(vb->usb_dev,
> + usb_sndctrlpipe(vb->usb_dev, 0), 0xec, 0x40,
> + 0x0000, 0x0000, admsg,
> + sizeof(struct vprbrd_adc_msg), 100);
> + if (ret != sizeof(struct vprbrd_adc_msg)) {
> + dev_err(&iio_dev->dev, "usb send error on adc read\n");
> + error = -EREMOTEIO;
> + }
Does it make sense to send out the second msg if the first one failed?
> +
> + ret = usb_control_msg(vb->usb_dev,
> + usb_rcvctrlpipe(vb->usb_dev, 0), 0xec, 0xc0,
> + 0x0000, 0x0000, admsg,
> + sizeof(struct vprbrd_adc_msg), 100);
> +
It would be good to have some defines for the magic constants used for
request and request_type.
> + *val = admsg->val;
> +
> + mutex_unlock(&vb->lock);
> +
> + if (ret != sizeof(struct vprbrd_adc_msg)) {
> + dev_err(&iio_dev->dev, "usb recv error on adc read\n");
> + error = -EREMOTEIO;
> + }
> +
> + if (error)
> + goto error;
> +
> + return IIO_VAL_INT;
> + }
> + error = -EINVAL;
> +error:
> + return error;
> +}
> +
> +static const struct iio_info vprbrd_adc_iio_info = {
> + .read_raw = &vprbrd_iio_read_raw,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static int __devinit vprbrd_adc_probe(struct platform_device *pdev)
> +{
> + struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
> + struct vprbrd_adc *adc;
> + struct iio_dev *iodev;
Usually this is called indio_dev, would be good for consistency if you'd do
this as well.
> + int ret;
> +
> + /* registering iio */
> + iodev = iio_device_alloc(sizeof(struct vprbrd_adc));
> + if (!iodev) {
> + dev_err(&pdev->dev, "failed allocating iio device\n");
> + return -ENOMEM;
> + }
> +
> + adc = iio_priv(iodev);
> + adc->vb = vb;
> + iodev->name = "viperboard adc";
> + iodev->dev.parent = &pdev->dev;
> + iodev->info = &vprbrd_adc_iio_info;
> + iodev->modes = INDIO_DIRECT_MODE;
> + iodev->channels = vprbrd_adc_iio_channels;
> + iodev->num_channels = ARRAY_SIZE(vprbrd_adc_iio_channels);
> +
> + ret = iio_device_register(iodev);
> + if (ret) {
> + dev_err(&pdev->dev, "could not register iio (adc)");
> + goto error;
> + }
> +
> + platform_set_drvdata(pdev, iodev);
> +
> + return 0;
> +
> +error:
> + iio_device_free(iodev);
> + return ret;
> +}
> +
> +static int __devexit vprbrd_adc_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *iodev = platform_get_drvdata(pdev);
> +
> + iio_device_unregister(iodev);
> + iio_device_free(iodev);
> +
> + return 0;
> +}
> +
> +static struct platform_driver vprbrd_adc_driver = {
> + .driver.name = "viperboard-adc",
> + .driver.owner = THIS_MODULE,
Same as with scan_type, usually this is written as
.driver = {
.name = ...
....
},
> + .probe = vprbrd_adc_probe,
> + .remove = __devexit_p(vprbrd_adc_remove),
> +};
> +
> +static int __init vprbrd_adc_init(void)
> +{
> + return platform_driver_register(&vprbrd_adc_driver);
> +}
> +subsys_initcall(vprbrd_adc_init);
> +
> +static void __exit vprbrd_adc_exit(void)
> +{
> + platform_driver_unregister(&vprbrd_adc_driver);
> +}
> +module_exit(vprbrd_adc_exit);
module_platform_driver(vprbrd_adc_driver);
> +
> +MODULE_AUTHOR("Lars Poeschel <poeschel@...onage.de>");
> +MODULE_DESCRIPTION("IIO ADC driver for Nano River Techs Viperboard");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:viperboard-adc");
> diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c
> index a25e07e..eb1cf89 100644
> --- a/drivers/mfd/viperboard.c
> +++ b/drivers/mfd/viperboard.c
> @@ -55,6 +55,9 @@ static struct mfd_cell vprbrd_devs[] = {
> {
> .name = "viperboard-i2c",
> },
> + {
> + .name = "viperboard-adc",
> + },
> };
>
> static int vprbrd_probe(struct usb_interface *interface,
--
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