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Date: Thu, 14 Feb 2013 21:55:59 +0100
From: Lars-Peter Clausen <lars@...afoo.de>
To: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
CC: linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-samsung-soc@...r.kernel.org, dianders@...omium.org,
gregkh@...uxfoundation.org, naveenkrishna.ch@...il.com
Subject: Re: [PATCH v6] iio: adc: add exynos adc driver under iio framwork
On 02/14/2013 01:11 PM, Naveen Krishna Chatradhi wrote:
> This patch adds New driver to support:
> 1. Supports ADC IF found on EXYNOS4412/EXYNOS5250
> and future SoCs from Samsung
> 2. Add ADC driver under iio/adc framework
> 3. Also adds the Documentation for device tree bindings
>
> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
Looks good to me. There is one bug left in debugfs_reg_access function though,
which should be fixed before the driver is merged.
> ---
> Changes since v1:
>
> 1. Fixed comments from Lars
> 2. Added support for ADC on EXYNOS5410
>
> Changes since v2:
>
> 1. Changed the instance name for (struct iio_dev *) to indio_dev
> 2. Changed devm_request_irq to request_irq
>
> Few doubts regarding the mappings and child device handling.
> Kindly, suggest me better methods.
>
> Changes since v3:
>
> 1. Added clk_prepare_disable and regulator_disable calls in _remove()
> 2. Moved init_completion before irq_request
> 3. Added NULL pointer check for devm_request_and_ioremap() return value.
> 4. Use number of channels as per the ADC version
> 5. Change the define ADC_V1_CHANNEL to ADC_CHANNEL
> 6. Update the Documentation to include EXYNOS5410 compatible
>
> Changes since v4:
>
> 1. if devm_request_and_ioremap() failes, free iio_device before returning
>
> Changes since v5:
>
> 1. Fixed comments from Olof (ADC hardware version handling)
> 2. Rebased on top of comming OF framework for IIO by "Guenter Roeck".
>
> .../bindings/arm/samsung/exynos5-adc.txt | 42 ++
> drivers/iio/adc/Kconfig | 7 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/exynos_adc.c | 438 ++++++++++++++++++++
> 4 files changed, 488 insertions(+)
> .../devicetree/bindings/arm/samsung/exynos-adc.txt | 52 +++
> drivers/iio/adc/Kconfig | 7 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/exynos_adc.c | 437 ++++++++++++++++++++
> 4 files changed, 497 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt
> create mode 100644 drivers/iio/adc/exynos_adc.c
>
> diff --git a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt
> new file mode 100644
> index 0000000..f686378
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt
> @@ -0,0 +1,52 @@
[...]
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 2d5f100..fabac2c 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_AD7791) += ad7791.o
> obj-$(CONFIG_AD7793) += ad7793.o
> obj-$(CONFIG_AD7887) += ad7887.o
> obj-$(CONFIG_AT91_ADC) += at91_adc.o
> +obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
> obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> obj-$(CONFIG_MAX1363) += max1363.o
> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
> new file mode 100644
> index 0000000..144a9e2
> --- /dev/null
> +++ b/drivers/iio/adc/exynos_adc.c
> @@ -0,0 +1,437 @@
> [...]
> +static int exynos_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val,
> + int *val2,
> + long mask)
> +{
> + struct exynos_adc *info = iio_priv(indio_dev);
> + u32 con1, con2;
> +
> + if (mask == IIO_CHAN_INFO_RAW) {
How about rewriting this as:
if (mask != IIO_CHAN_INFO_RAW)
return -EINVAL;
mutex_lock(...);
...
keeps the indention level low.
> + mutex_lock(&indio_dev->mlock);
> +
> + /* Select the channel to be used and Trigger conversion */
> + if (info->version == ADC_V2) {
> + con2 = readl(ADC_V2_CON2(info->regs));
> + con2 &= ~ADC_V2_CON2_ACH_MASK;
> + con2 |= ADC_V2_CON2_ACH_SEL(chan->address);
> + writel(con2, ADC_V2_CON2(info->regs));
> +
> + con1 = readl(ADC_V2_CON1(info->regs));
> + writel(con1 | ADC_CON_EN_START,
> + ADC_V2_CON1(info->regs));
> + } else {
> + writel(chan->address, ADC_V1_MUX(info->regs));
> +
> + con1 = readl(ADC_V1_CON(info->regs));
> + writel(con1 | ADC_CON_EN_START,
> + ADC_V1_CON(info->regs));
> + }
> +
> + wait_for_completion(&info->completion);
I'd add at least a timeout so you don't get stuck here forever if something
goes wrong.
> + *val = info->value;
> +
> + mutex_unlock(&indio_dev->mlock);
> +
> + return IIO_VAL_INT;
> + }
> +
> + return -EINVAL;
> +}
> +
[...]
> +static int exynos_adc_reg_access(struct iio_dev *indio_dev,
> + unsigned reg, unsigned writeval,
> + unsigned *readval)
> +{
> + struct exynos_adc *info = iio_priv(indio_dev);
> + u32 ret;
> +
> + mutex_lock(&indio_dev->mlock);
I don't think the locking here is necessary.
> +
> + if (readval != NULL) {
> + ret = readl(info->regs + reg);
> + *readval = ret;
At the end of the function you return the read value, you should return 0 on
success though.
> + } else
> + ret = -EINVAL;
> +
> + mutex_unlock(&indio_dev->mlock);
How about rewriting the function as:
if (readval == NULL)
return -EINVAL;
*readval = readl(info->regs + reg)
return 0;
> +
> + return ret;
> +}
[...]
> +
> +static int exynos_adc_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct exynos_adc *info = iio_priv(indio_dev);
> +
Do you need to remove the child devices here as well?
> + regulator_disable(info->vdd);
> + clk_disable_unprepare(info->clk);
> + iio_device_unregister(indio_dev);
> + free_irq(info->irq, info);
> + iio_device_free(indio_dev);
> +
> + return 0;
> +}
--
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