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

[Icenowy Zheng <icenowy@aosc.xyz>]

14.03.2017, 05:08, "Jonathan Cameron" <jic23@kernel.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@free-electrons.com>
>
> Talk me through why it makes sense to do this rather than simply spin out
> a really simple thermal driver for the A33?

According to him the A33 thermal sensor is a simplified version of the GPADC.

I have already did a simple thermal driver ~8 months ago, but is rejected for
this reason.

>
> 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)
>
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