Message-ID: <51E05F6C.1060506@metafoo.de>
Date: Fri, 12 Jul 2013 21:56:28 +0200
From: Lars-Peter Clausen <lars@metafoo.de>
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To: Oleksandr Kozaruk <oleksandr.kozaruk@ti.com>
CC: tony@atomide.com, benoit.cousson@linaro.org, rnayak@ti.com,
        peter.ujfalusi@ti.com, kishon@ti.com, jic23@cam.ac.uk,
        grant.likely@linaro.org, rob.herring@calxeda.com,
        sameo@linux.intel.com, ch.naveen@samsung.com, poeschel@lemonage.de,
        milo.kim@ti.com, balajitk@ti.com, gg@slimlogic.co.uk,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-iio@vger.kernel.org, devicetree-discuss@lists.ozlabs.org,
        linux-omap@vger.kernel.org
Subject: Re: [PATCH v3 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver
References: <1373613482-28390-1-git-send-email-oleksandr.kozaruk@ti.com> <1373613482-28390-3-git-send-email-oleksandr.kozaruk@ti.com>
In-Reply-To: <1373613482-28390-3-git-send-email-oleksandr.kozaruk@ti.com>
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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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