[RFC PATCH 2/3] iio: adc: sun4i-gpadc-iio: add support for H3 thermal sensor

[jic23@kernel.org (Jonathan Cameron)]

On 29/03/17 07:54, Quentin Schulz wrote:
> Hi,
> 
> On 28/03/2017 19:30, Icenowy Zheng wrote:
>> This adds support for the Allwinner H3 thermal sensor.
>>
>> Allwinner H3 has a thermal sensor like the one in A33, but have its
>> registers nearly all re-arranged, sample clock moved to CCU and a pair
>> of bus clock and reset added. It's also the base of newer SoCs' thermal
>> sensors.
>>
>> An option is added to gpadc_data struct, to indicate whether this device
>> is a new-generation Allwinner thermal sensor.
>>
>> The thermal sensors on A64 and H5 is like the one on H3, but with of
>> course different formula factors.
>>
>> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
>> ---
>>  drivers/iio/adc/sun4i-gpadc-iio.c | 130 ++++++++++++++++++++++++++++++++------
>>  include/linux/mfd/sun4i-gpadc.h   |  33 +++++++++-
>>  2 files changed, 141 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/iio/adc/sun4i-gpadc-iio.c b/drivers/iio/adc/sun4i-gpadc-iio.c
>> index 74705aa37982..7512b1cae877 100644
>> --- a/drivers/iio/adc/sun4i-gpadc-iio.c
>> +++ b/drivers/iio/adc/sun4i-gpadc-iio.c
>> @@ -22,6 +22,7 @@
>>   * shutdown for not being used.
>>   */
>>  
>> +#include <linux/clk.h>
>>  #include <linux/completion.h>
>>  #include <linux/interrupt.h>
>>  #include <linux/io.h>
>> @@ -31,6 +32,7 @@
>>  #include <linux/platform_device.h>
>>  #include <linux/pm_runtime.h>
>>  #include <linux/regmap.h>
>> +#include <linux/reset.h>
>>  #include <linux/thermal.h>
>>  #include <linux/delay.h>
>>  
>> @@ -56,6 +58,7 @@ struct gpadc_data {
>>  	unsigned int	tp_adc_select;
>>  	unsigned int	(*adc_chan_select)(unsigned int chan);
>>  	unsigned int	adc_chan_mask;
>> +	bool		gen2_ths;
>>  };
>>  
> 
> Instead of a boolean, give the TEMP_DATA register address.
> 
>>  static const struct gpadc_data sun4i_gpadc_data = {
>> @@ -88,7 +91,20 @@ static const struct gpadc_data sun6i_gpadc_data = {
>>  static const struct gpadc_data sun8i_a33_gpadc_data = {
>>  	.temp_offset = -1662,
>>  	.temp_scale = 162,
>> -	.tp_mode_en = SUN8I_GPADC_CTRL1_CHOP_TEMP_EN,
>> +	.tp_mode_en = SUN8I_A23_GPADC_CTRL1_CHOP_TEMP_EN,
>> +};
> 
> Separate patch for this?
Indeed, ideal to rework original first (really easy to review)
then add support for new part.
> 
>> +
>> +static const struct gpadc_data sun8i_h3_gpadc_data = {
>> +	/*
>> +	 * The original formula on the datasheet seems to be wrong.
>> +	 * These factors are calculated based on the formula in the BSP
>> +	 * kernel, which is originally Tem = 217 - (T / 8.253), in which Tem
>> +	 * is the temperature in Celsius degree and T is the raw value
>> +	 * from the sensor.
>> +	 */
>> +	.temp_offset = -1791,
>> +	.temp_scale = -121,
>> +	.gen2_ths = true,
>>  };
>>  
>>  struct sun4i_gpadc_iio {
>> @@ -103,6 +119,9 @@ struct sun4i_gpadc_iio {
>>  	atomic_t			ignore_temp_data_irq;
>>  	const struct gpadc_data		*data;
>>  	bool				no_irq;
>> +	struct clk			*ths_bus_clk;
>> +	struct clk			*ths_clk;
>> +	struct reset_control		*reset;
>>  	/* prevents concurrent reads of temperature and ADC */
>>  	struct mutex			mutex;
>>  };
>> @@ -274,7 +293,11 @@ static int sun4i_gpadc_temp_read(struct iio_dev *indio_dev, int *val)
>>  	if (info->no_irq) {
>>  		pm_runtime_get_sync(indio_dev->dev.parent);
>>  
>> -		regmap_read(info->regmap, SUN4I_GPADC_TEMP_DATA, val);
>> +		if (info->data->gen2_ths)
>> +			regmap_read(info->regmap, SUN8I_H3_GPADC_TEMP_DATA,
>> +				    val);
>> +		else
>> +			regmap_read(info->regmap, SUN4I_GPADC_TEMP_DATA, val);
>>  
> 
> Instead of gen2_ths, use the TEMP_DATA register address.
Agreed. Put a set of register addresses into the gpadc_data structure.
Both more flexible and easier to read.
> 
>>  		pm_runtime_mark_last_busy(indio_dev->dev.parent);
>>  		pm_runtime_put_autosuspend(indio_dev->dev.parent);
>> @@ -386,10 +409,15 @@ static int sun4i_gpadc_runtime_suspend(struct device *dev)
>>  {
>>  	struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
>>  
>> -	/* Disable the ADC on IP */
>> -	regmap_write(info->regmap, SUN4I_GPADC_CTRL1, 0);
>> -	/* Disable temperature sensor on IP */
>> -	regmap_write(info->regmap, SUN4I_GPADC_TPR, 0);
>> +	if (info->data->gen2_ths) {
>> +		/* Disable temperature sensor */
>> +		regmap_write(info->regmap, SUN8I_H3_GPADC_CTRL2, 0);
>> +	} else {
>> +		/* Disable the ADC on IP */
>> +		regmap_write(info->regmap, SUN4I_GPADC_CTRL1, 0);
>> +		/* Disable temperature sensor on IP */
>> +		regmap_write(info->regmap, SUN4I_GPADC_TPR, 0);
>> +	}
>>  
> 
> Either use another register address or add a suspend function to struct
> gpadc_data which will be different for each version of the IP.
> 
>>  	return 0;
>>  }
>> @@ -398,19 +426,36 @@ static int sun4i_gpadc_runtime_resume(struct device *dev)
>>  {
>>  	struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
>>  
>> -	/* clkin = 6MHz */
>> -	regmap_write(info->regmap, SUN4I_GPADC_CTRL0,
>> -		     SUN4I_GPADC_CTRL0_ADC_CLK_DIVIDER(2) |
>> -		     SUN4I_GPADC_CTRL0_FS_DIV(7) |
>> -		     SUN4I_GPADC_CTRL0_T_ACQ(63));
>> -	regmap_write(info->regmap, SUN4I_GPADC_CTRL1, info->data->tp_mode_en);
>> -	regmap_write(info->regmap, SUN4I_GPADC_CTRL3,
>> -		     SUN4I_GPADC_CTRL3_FILTER_EN |
>> -		     SUN4I_GPADC_CTRL3_FILTER_TYPE(1));
>> -	/* period = SUN4I_GPADC_TPR_TEMP_PERIOD * 256 * 16 / clkin; ~0.6s */
>> -	regmap_write(info->regmap, SUN4I_GPADC_TPR,
>> -		     SUN4I_GPADC_TPR_TEMP_ENABLE |
>> -		     SUN4I_GPADC_TPR_TEMP_PERIOD(800));
>> +	if (info->data->gen2_ths) {
>> +		regmap_write(info->regmap, SUN8I_H3_GPADC_CTRL2,
>> +			     SUN8I_H3_GPADC_CTRL2_TEMP_SENSE_EN |
>> +			     SUN8I_H3_GPADC_CTRL2_T_ACQ1(31));
>> +		regmap_write(info->regmap, SUN4I_GPADC_CTRL0,
>> +			     SUN4I_GPADC_CTRL0_T_ACQ(31));
>> +		regmap_write(info->regmap, SUN8I_H3_GPADC_CTRL3,
>> +			     SUN4I_GPADC_CTRL3_FILTER_EN |
>> +			     SUN4I_GPADC_CTRL3_FILTER_TYPE(1));
>> +		regmap_write(info->regmap, SUN8I_H3_GPADC_INTC,
>> +			     SUN8I_H3_GPADC_INTC_TEMP_PERIOD(800));
>> +	} else {
>> +		/* clkin = 6MHz */
>> +		regmap_write(info->regmap, SUN4I_GPADC_CTRL0,
>> +			     SUN4I_GPADC_CTRL0_ADC_CLK_DIVIDER(2) |
>> +			     SUN4I_GPADC_CTRL0_FS_DIV(7) |
>> +			     SUN4I_GPADC_CTRL0_T_ACQ(63));
Looks like you'll need something like a function pointer in your
_data structure as well to cover cases where they are totally
different like here.  or you could use regmap fields if they map
reasonably well... (doesn't look like they do though!)
>> +		regmap_write(info->regmap, SUN4I_GPADC_CTRL1,
>> +			     info->data->tp_mode_en);
>> +		regmap_write(info->regmap, SUN4I_GPADC_CTRL3,
>> +			     SUN4I_GPADC_CTRL3_FILTER_EN |
>> +			     SUN4I_GPADC_CTRL3_FILTER_TYPE(1));
>> +		/*
>> +		 * period = SUN4I_GPADC_TPR_TEMP_PERIOD * 256 * 16 / clkin;
>> +		 * ~0.6s
>> +		 */
>> +		regmap_write(info->regmap, SUN4I_GPADC_TPR,
>> +			     SUN4I_GPADC_TPR_TEMP_ENABLE |
>> +			     SUN4I_GPADC_TPR_TEMP_PERIOD(800));
>> +	}
>>  
> 
> Same here as suspend function?
> 
>>  	return 0;
>>  }
>> @@ -494,6 +539,10 @@ static const struct of_device_id sun4i_gpadc_of_id[] = {
>>  		.compatible = "allwinner,sun8i-a33-ths",
>>  		.data = &sun8i_a33_gpadc_data,
>>  	},
>> +	{
>> +		.compatible = "allwinner,sun8i-h3-ths",
>> +		.data = &sun8i_h3_gpadc_data,
>> +	},
>>  	{ /* sentinel */ }
>>  };
>>  
>> @@ -529,6 +578,43 @@ static int sun4i_gpadc_probe_dt(struct platform_device *pdev,
>>  		return ret;
>>  	}
>>  
>> +	if (info->data->gen2_ths) {
>> +		info->reset = devm_reset_control_get(&pdev->dev, NULL);
>> +		if (IS_ERR(info->reset)) {
>> +			ret = PTR_ERR(info->reset);
>> +			return ret;
>> +		}
>> +
>> +		ret = reset_control_deassert(info->reset);
>> +		if (ret)
>> +			return ret;
>> +
>> +		info->ths_bus_clk = devm_clk_get(&pdev->dev, "bus");
>> +		if (IS_ERR(info->ths_bus_clk)) {
>> +			ret = PTR_ERR(info->ths_bus_clk);
>> +			return ret;
>> +		}
>> +
>> +		ret = clk_prepare_enable(info->ths_bus_clk);
>> +		if (ret)
>> +			return ret;
>> +
>> +		info->ths_clk = devm_clk_get(&pdev->dev, "ths");
>> +		if (IS_ERR(info->ths_clk)) {
>> +			ret = PTR_ERR(info->ths_clk);
>> +			return ret;
>> +		}
>> +
>> +		/* Running at 6MHz */
>> +		ret = clk_set_rate(info->ths_clk, 6000000);
>> +		if (ret)
>> +			return ret;
>> +
>> +		ret = clk_prepare_enable(info->ths_clk);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>>  	if (!IS_ENABLED(CONFIG_THERMAL_OF))
>>  		return 0;
>>  
>> @@ -691,6 +777,12 @@ static int sun4i_gpadc_remove(struct platform_device *pdev)
>>  	if (!info->no_irq && IS_ENABLED(CONFIG_THERMAL_OF))
>>  		iio_map_array_unregister(indio_dev);
>>  
>> +	if (info->data->gen2_ths) {
>> +		clk_disable_unprepare(info->ths_clk);
>> +		clk_disable_unprepare(info->ths_bus_clk);
>> +		reset_control_deassert(info->reset);
>> +	}
>> +
> 
> I'm not really fond of using this boolean as I don't see it being
> possibly reused for any other SoCs that has a GPADC or THS.
> 
> Here, you could make use of a list/array of clk which then can be reused
> for other SoCs just by changing the list. Add a default rate to the
> gpadc_data structure and you're go to go.
> 
>>  	return 0;
>>  }
>>  
>> diff --git a/include/linux/mfd/sun4i-gpadc.h b/include/linux/mfd/sun4i-gpadc.h
>> index 139872c2e0fe..f794a2988a93 100644
>> --- a/include/linux/mfd/sun4i-gpadc.h
>> +++ b/include/linux/mfd/sun4i-gpadc.h
>> @@ -38,9 +38,12 @@
>>  #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)
>> +/* TP_CTRL1 bits for sun8i A23/A33 SoCs */
>> +#define SUN8I_A23_GPADC_CTRL1_CHOP_TEMP_EN		BIT(8)
>> +#define SUN8I_A23_GPADC_CTRL1_GPADC_CALI_EN		BIT(7)
>> +
> 
> Different patch for these?
Looks to me like you want a precursor that reworks the driver to
be ready to support the new part, followed by a patch that actually
introduces the new part.

Jonathan
> 
> Thanks,
> Quentin
>