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Message-ID: <51E3E362.6090903@ti.com>
Date: Mon, 15 Jul 2013 14:56:18 +0300
From: Grygorii Strashko <grygorii.strashko@...com>
To: Lars-Peter Clausen <lars@...afoo.de>
CC: Oleksandr Kozaruk <oleksandr.kozaruk@...com>, <tony@...mide.com>,
<benoit.cousson@...aro.org>, <rnayak@...com>,
<peter.ujfalusi@...com>, <kishon@...com>, <jic23@....ac.uk>,
<grant.likely@...aro.org>, <rob.herring@...xeda.com>,
<sameo@...ux.intel.com>, <ch.naveen@...sung.com>,
<poeschel@...onage.de>, <milo.kim@...com>, <balajitk@...com>,
<gg@...mlogic.co.uk>, <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-iio@...r.kernel.org>,
<devicetree-discuss@...ts.ozlabs.org>, <linux-omap@...r.kernel.org>
Subject: Re: [PATCH v3 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver
Hi All,
I have a question regarding this patch and IIO in general
- Does IIO provide sync mechanism with system wide suspend/resume or
this should be handled by each driver itself?
What if during system suspend iio_read_channel_raw() (or any other
consumer API) will be called after gpadc driver have been suspended
already? (I did some investigation and seems it's possible - Am I right?)
If no, could "info_exist_lock" be reused for such purposes?
Regards,
-grygorii
On 07/12/2013 10:56 PM, Lars-Peter Clausen wrote:
>
> A couple of comments inline.
>
> On 07/12/2013 09:18 AM, Oleksandr Kozaruk wrote:
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index ab0767e6..87d699e 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -157,4 +157,12 @@ config VIPERBOARD_ADC
>> Say yes here to access the ADC part of the Nano River
>> Technologies Viperboard.
>>
>> +config TWL6030_GPADC
>> + tristate "TWL6030 GPADC (General Purpose A/D Convertor) Support"
>> + depends on TWL4030_CORE
>> + default n
>> + help
>> + Say yes here if you want support for the TWL6030 General Purpose
>> + A/D Convertor.
>> +
>
> Keep it in alphabetical order
>
>> endmenu
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index 0a825be..8b05633 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -17,3 +17,4 @@ obj-$(CONFIG_MAX1363) += max1363.o
>> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>> obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
>> obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
>> +obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
>
> Same here.
>
>> diff --git a/drivers/iio/adc/twl6030-gpadc.c
>> b/drivers/iio/adc/twl6030-gpadc.c
>> new file mode 100644
>> index 0000000..6ceb789
>> --- /dev/null
>> +++ b/drivers/iio/adc/twl6030-gpadc.c
>> @@ -0,0 +1,1019 @@
> [...]
>> +static u8 twl6032_channel_to_reg(int channel)
>> +{
>> + return TWL6032_GPADC_GPCH0_LSB;
>
> There is more than one channel, isn't there?
>
> [...]
> > +static int twl6030_gpadc_read_raw(struct iio_dev *indio_dev,
> > + const struct iio_chan_spec *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
> > + int ret = -EINVAL;
> > +
> > + mutex_lock(&gpadc->lock);
> > +
> > + ret = gpadc->pdata->start_conversion(chan->channel);
> > + if (ret) {
> > + dev_err(gpadc->dev, "failed to start conversion\n");
> > + goto err;
> > + }
> > + /* wait for conversion to complete */
> > + wait_for_completion_interruptible_timeout(&gpadc->irq_complete,
> > + msecs_to_jiffies(5000));
>
> wait_for_completion_interruptible_timeout() can return either a negative
> error code if it was interrupted, 0 if it timed out, or a positive value
> if it was successfully completed. You need to handle all three cases.
> Have a look at other existing drivers to see how to do this properly.
>
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + ret = twl6030_gpadc_get_raw(gpadc, chan->channel, val);
> > + ret = ret ? -EIO : IIO_VAL_INT;
> > + break;
> > +
> > + case IIO_CHAN_INFO_PROCESSED:
> > + ret = twl6030_gpadc_get_processed(gpadc, chan->channel, val);
> > + ret = ret ? -EIO : IIO_VAL_INT;
> > + break;
> > +
> > + default:
> > + break;
> > + }
> > +err:
> > + mutex_unlock(&gpadc->lock);
> > +
> > + return ret;
> > +}
>
>> +}
>> +
> [...]
>> +static int twl6030_gpadc_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct twl6030_gpadc_data *gpadc;
>> + const struct twl6030_gpadc_platform_data *pdata;
>> + const struct of_device_id *match;
>> + struct iio_dev *indio_dev;
>> + int irq;
>> + int ret = 0;
>> +
>> + match = of_match_device(of_match_ptr(of_twl6030_match_tbl), dev);
>> + pdata = match ? match->data : dev->platform_data;
>> +
>> + if (!pdata)
>> + return -EINVAL;
>> +
>> + indio_dev = iio_device_alloc(sizeof(struct twl6030_gpadc_data));
>
> sizeof(*gpadc)
>
>> + if (!indio_dev) {
>> + dev_err(dev, "failed allocating iio device\n");
>> + ret = -ENOMEM;
>> + }
>> +
>> + gpadc = iio_priv(indio_dev);
>> +
>> + gpadc->twl6030_cal_tbl = devm_kzalloc(dev,
>> + sizeof(struct twl6030_chnl_calib) *
>> + pdata->nchannels, GFP_KERNEL);
>> + if (!gpadc->twl6030_cal_tbl)
>> + goto err;
>> +
>> + gpadc->dev = dev;
>> + gpadc->pdata = pdata;
>> +
>> + platform_set_drvdata(pdev, indio_dev);
>> + mutex_init(&gpadc->lock);
>> + init_completion(&gpadc->irq_complete);
>> +
>> + ret = pdata->calibrate(gpadc);
>> + if (ret < 0) {
>> + dev_err(&pdev->dev, "failed to read calibration registers\n");
>> + goto err;
>> + }
>> +
>> + irq = platform_get_irq(pdev, 0);
>> + if (irq < 0) {
>> + dev_err(&pdev->dev, "failed to get irq\n");
>> + goto err;
>> + }
>> +
>> + ret = devm_request_threaded_irq(dev, irq, NULL,
>> + twl6030_gpadc_irq_handler,
>> + IRQF_ONESHOT, "twl6030_gpadc", gpadc);
>
> You access memory in the interrupt handler which is freed before the
> interrupt handler is freed.
>
>> + if (ret) {
>> + dev_dbg(&pdev->dev, "could not request irq\n");
>> + goto err;
>> + }
>> +
>> + ret = twl6030_gpadc_enable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
>> + if (ret < 0) {
>> + dev_err(&pdev->dev, "failed to enable GPADC interrupt\n");
>> + goto err;
>> + }
>> + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
>> + TWL6030_REG_TOGGLE1);
>> + if (ret < 0) {
>> + dev_err(&pdev->dev, "failed to enable GPADC module\n");
>> + goto err;
>> + }
>> +
>> + indio_dev->name = DRIVER_NAME;
>> + indio_dev->dev.parent = dev;
>> + indio_dev->info = &twl6030_gpadc_iio_info;
>> + indio_dev->modes = INDIO_DIRECT_MODE;
>> + indio_dev->channels = pdata->iio_channels;
>> + indio_dev->num_channels = pdata->nchannels;
>> +
>> + ret = iio_device_register(indio_dev);
>> + if (ret)
>> + goto err;
>> +
>> + return ret;
>> +err:
>> + iio_device_free(indio_dev);
>> + return ret;
>> +}
>> +
> [...]
>> +static int twl6030_gpadc_suspend(struct device *pdev)
>> +{
>> + int ret;
>> +
>> + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCR,
>> + TWL6030_REG_TOGGLE1);
>> + if (ret)
>> + dev_err(pdev, "error reseting GPADC (%d)!\n", ret);
>> +
>> + return 0;
>> +};
>> +
>> +static int twl6030_gpadc_resume(struct device *pdev)
>> +{
>> + int ret;
>> +
>> + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
>> + TWL6030_REG_TOGGLE1);
>> + if (ret)
>> + dev_err(pdev, "error setting GPADC (%d)!\n", ret);
>> +
>> + return 0;
>> +};
>> +
>> +static const struct dev_pm_ops twl6030_gpadc_pm_ops = {
>> + .suspend = twl6030_gpadc_suspend,
>> + .resume = twl6030_gpadc_resume,
>> +};
>
> SIMPLE_DEV_PM_OPS?
>
> [...]
> --
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