Re: [PATCH v2 08/11] iio: adc: sun4i-gpadc-iio: add support for A33 thermal sensor

[Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On 10/03/17 10:39, Quentin Schulz wrote:
> This adds support for the Allwinner A33 thermal sensor.
> 
> Unlike the A10, A13 and A31, the Allwinner A33 only has one channel
> which is dedicated to the thermal sensor. Moreover, its thermal sensor
> does not generate interruptions, thus we only need to directly read the
> register storing the temperature value.
> 
> The MFD used by the A10, A13 and A31, was created to avoid breaking the
> DT binding, but since the nodes for the ADC weren't there for the A33,
> it is not needed.
> 
> Signed-off-by: Quentin Schulz <quentin.schulz-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>

Talk me through why it makes sense to do this rather than simply spin out
a really simple thermal driver for the A33?

I'm not against what you have here, but don't feel it has been fully argued.

Jonathan
> ---
> 
> v2:
>   - removed added comments in Kconfig,
>   - simplified Kconfig depends on condition,
>   - removed THERMAL_OF requirement for sun8i,
>   - renamed sun8i_gpadc_channels to sun8i_a33_gpadc_channels,
>   - renamed use_dt boolean in no_irq as it reflects better why we need it,
>   - removed spurious/unneeded modifications done in v1,
> 
>  drivers/iio/adc/Kconfig           |   2 +-
>  drivers/iio/adc/sun4i-gpadc-iio.c | 100 ++++++++++++++++++++++++++++++++++++--
>  include/linux/mfd/sun4i-gpadc.h   |   4 ++
>  3 files changed, 102 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 9f8b4b1..8c8ead6 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -562,7 +562,7 @@ config STX104
>  config SUN4I_GPADC
>  	tristate "Support for the Allwinner SoCs GPADC"
>  	depends on IIO
> -	depends on MFD_SUN4I_GPADC
> +	depends on MFD_SUN4I_GPADC || MACH_SUN8I
>  	help
>  	  Say yes here to build support for Allwinner (A10, A13 and A31) SoCs
>  	  GPADC. This ADC provides 4 channels which can be used as an ADC or as
> diff --git a/drivers/iio/adc/sun4i-gpadc-iio.c b/drivers/iio/adc/sun4i-gpadc-iio.c
> index 7cb997a..70684cd 100644
> --- a/drivers/iio/adc/sun4i-gpadc-iio.c
> +++ b/drivers/iio/adc/sun4i-gpadc-iio.c
> @@ -85,6 +85,12 @@ static const struct gpadc_data sun6i_gpadc_data = {
>  	.adc_chan_mask = SUN6I_GPADC_CTRL1_ADC_CHAN_MASK,
>  };
>  
> +static const struct gpadc_data sun8i_a33_gpadc_data = {
> +	.temp_offset = -1662,
> +	.temp_scale = 162,
> +	.tp_mode_en = SUN8I_GPADC_CTRL1_CHOP_TEMP_EN,
> +};
> +
>  struct sun4i_gpadc_iio {
>  	struct iio_dev			*indio_dev;
>  	struct completion		completion;
> @@ -96,6 +102,7 @@ struct sun4i_gpadc_iio {
>  	unsigned int			temp_data_irq;
>  	atomic_t			ignore_temp_data_irq;
>  	const struct gpadc_data		*data;
> +	bool				no_irq;
>  	/* prevents concurrent reads of temperature and ADC */
>  	struct mutex			mutex;
>  };
> @@ -138,6 +145,23 @@ static const struct iio_chan_spec sun4i_gpadc_channels_no_temp[] = {
>  	SUN4I_GPADC_ADC_CHANNEL(3, "adc_chan3"),
>  };
>  
> +static const struct iio_chan_spec sun8i_a33_gpadc_channels[] = {
> +	{
> +		.type = IIO_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE) |
> +				      BIT(IIO_CHAN_INFO_OFFSET),
> +		.datasheet_name = "temp_adc",
> +	},
> +};
> +
> +static const struct regmap_config sun4i_gpadc_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.fast_io = true,
> +};
> +
>  static int sun4i_prepare_for_irq(struct iio_dev *indio_dev, int channel,
>  				 unsigned int irq)
>  {
> @@ -247,6 +271,17 @@ static int sun4i_gpadc_temp_read(struct iio_dev *indio_dev, int *val)
>  {
>  	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>  
> +	if (info->no_irq) {
> +		pm_runtime_get_sync(indio_dev->dev.parent);
> +
> +		regmap_read(info->regmap, SUN4I_GPADC_TEMP_DATA, val);
> +
> +		pm_runtime_mark_last_busy(indio_dev->dev.parent);
> +		pm_runtime_put_autosuspend(indio_dev->dev.parent);
> +
> +		return 0;
> +	}
> +
>  	return sun4i_gpadc_read(indio_dev, 0, val, info->temp_data_irq);
>  }
>  
> @@ -454,6 +489,58 @@ static int sun4i_irq_init(struct platform_device *pdev, const char *name,
>  	return 0;
>  }
>  
> +static const struct of_device_id sun4i_gpadc_of_id[] = {
> +	{
> +		.compatible = "allwinner,sun8i-a33-gpadc-iio",
> +		.data = &sun8i_a33_gpadc_data,
> +	},
> +	{ /* sentinel */ }
> +};
> +
> +static int sun4i_gpadc_probe_dt(struct platform_device *pdev,
> +				struct iio_dev *indio_dev)
> +{
> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
> +	const struct of_device_id *of_dev;
> +	struct thermal_zone_device *tzd;
> +	struct resource *mem;
> +	void __iomem *base;
> +	int ret;
> +
> +	of_dev = of_match_device(sun4i_gpadc_of_id, &pdev->dev);
> +	if (!of_dev)
> +		return -ENODEV;
> +
> +	info->no_irq = true;
> +	info->data = (struct gpadc_data *)of_dev->data;
> +	indio_dev->num_channels = ARRAY_SIZE(sun8i_a33_gpadc_channels);
> +	indio_dev->channels = sun8i_a33_gpadc_channels;
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(&pdev->dev, mem);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	info->regmap = devm_regmap_init_mmio(&pdev->dev, base,
> +					     &sun4i_gpadc_regmap_config);
> +	if (IS_ERR(info->regmap)) {
> +		ret = PTR_ERR(info->regmap);
> +		dev_err(&pdev->dev, "failed to init regmap: %d\n", ret);
> +		return ret;
> +	}
> +
> +	if (!IS_ENABLED(THERMAL_OF))
> +		return 0;
> +
> +	tzd = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, info,
> +						   &sun4i_ts_tz_ops);
> +	if (IS_ERR(tzd))
> +		dev_err(&pdev->dev, "could not register thermal sensor: %ld\n",
> +			PTR_ERR(tzd));
> +
> +	return PTR_ERR_OR_ZERO(tzd);
> +}
> +
>  static int sun4i_gpadc_probe_mfd(struct platform_device *pdev,
>  				 struct iio_dev *indio_dev)
>  {
> @@ -462,6 +549,7 @@ static int sun4i_gpadc_probe_mfd(struct platform_device *pdev,
>  		dev_get_drvdata(pdev->dev.parent);
>  	int ret;
>  
> +	info->no_irq = false;
>  	info->regmap = sun4i_gpadc_dev->regmap;
>  
>  	indio_dev->num_channels = ARRAY_SIZE(sun4i_gpadc_channels);
> @@ -561,7 +649,11 @@ static int sun4i_gpadc_probe(struct platform_device *pdev)
>  	indio_dev->info = &sun4i_gpadc_iio_info;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  
> -	ret = sun4i_gpadc_probe_mfd(pdev, indio_dev);
> +	if (pdev->dev.of_node)
> +		ret = sun4i_gpadc_probe_dt(pdev, indio_dev);
> +	else
> +		ret = sun4i_gpadc_probe_mfd(pdev, indio_dev);
> +
>  	if (ret)
>  		return ret;
>  
> @@ -580,7 +672,7 @@ static int sun4i_gpadc_probe(struct platform_device *pdev)
>  	return 0;
>  
>  err_map:
> -	if (IS_ENABLED(CONFIG_THERMAL_OF))
> +	if (!info->no_irq && IS_ENABLED(CONFIG_THERMAL_OF))
>  		iio_map_array_unregister(indio_dev);
>  
>  	pm_runtime_put(&pdev->dev);
> @@ -592,10 +684,11 @@ static int sun4i_gpadc_probe(struct platform_device *pdev)
>  static int sun4i_gpadc_remove(struct platform_device *pdev)
>  {
>  	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>  
>  	pm_runtime_put(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
> -	if (IS_ENABLED(CONFIG_THERMAL_OF))
> +	if (!info->no_irq && IS_ENABLED(CONFIG_THERMAL_OF))
>  		iio_map_array_unregister(indio_dev);
>  
>  	return 0;
> @@ -611,6 +704,7 @@ static const struct platform_device_id sun4i_gpadc_id[] = {
>  static struct platform_driver sun4i_gpadc_driver = {
>  	.driver = {
>  		.name = "sun4i-gpadc-iio",
> +		.of_match_table = sun4i_gpadc_of_id,
>  		.pm = &sun4i_gpadc_pm_ops,
>  	},
>  	.id_table = sun4i_gpadc_id,
> diff --git a/include/linux/mfd/sun4i-gpadc.h b/include/linux/mfd/sun4i-gpadc.h
> index 509e736..139872c 100644
> --- a/include/linux/mfd/sun4i-gpadc.h
> +++ b/include/linux/mfd/sun4i-gpadc.h
> @@ -38,6 +38,10 @@
>  #define SUN6I_GPADC_CTRL1_ADC_CHAN_SELECT(x)		(GENMASK(3, 0) & BIT(x))
>  #define SUN6I_GPADC_CTRL1_ADC_CHAN_MASK			GENMASK(3, 0)
>  
> +/* TP_CTRL1 bits for sun8i SoCs */
> +#define SUN8I_GPADC_CTRL1_CHOP_TEMP_EN			BIT(8)
> +#define SUN8I_GPADC_CTRL1_GPADC_CALI_EN			BIT(7)
> +
>  #define SUN4I_GPADC_CTRL2				0x08
>  
>  #define SUN4I_GPADC_CTRL2_TP_SENSITIVE_ADJUST(x)	((GENMASK(3, 0) & (x)) << 28)
>