Re: [PATCH 1/3] mfd: add support for Allwinner SoCs ADC

[Jonathan Cameron]

On 28/06/16 09:18, Quentin Schulz wrote:
> The Allwinner SoCs all have an ADC that can also act as a touchscreen
> controller and a thermal sensor. For now, only the ADC and the thermal
> sensor drivers are probed by the MFD, the touchscreen controller support
> will be added later.
> 
> Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>
The code looks fine to me. The 'controversial' bit of this is listing
iio-hwmon as an mfd child to get it to probe as a result of this being
present.  My immediately thought is that it should be separately
described in the devicetree and hence instantiated outside of this driver.

Perhaps you could describe your reasoning for doing it this way?

Thanks,

Jonathan
> ---
>  drivers/mfd/Kconfig                 |  14 +++
>  drivers/mfd/Makefile                |   2 +
>  drivers/mfd/sunxi-gpadc-mfd.c       | 188 ++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/sunxi-gpadc-mfd.h |  14 +++
>  4 files changed, 218 insertions(+)
>  create mode 100644 drivers/mfd/sunxi-gpadc-mfd.c
>  create mode 100644 include/linux/mfd/sunxi-gpadc-mfd.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index eea61e3..1663db9 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -82,6 +82,20 @@ config MFD_ATMEL_FLEXCOM
>  	  by the probe function of this MFD driver according to a device tree
>  	  property.
>  
> +config MFD_SUNXI_ADC
> +	tristate "ADC MFD core driver for sunxi platforms"
> +	select MFD_CORE
> +	select REGMAP_MMIO
> +	help
> +	  Select this to get support for Allwinner SoCs (A10, A13 and A31) ADC.
> +	  This driver will only map the hardware interrupt and registers, you
> +	  have to select individual drivers based on this MFD to be able to use
> +	  the ADC or the thermal sensor. This will try to probe the ADC driver
> +	  sunxi-gpadc-iio and the hwmon driver iio_hwmon.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called sunxi-gpadc-mfd.
> +
>  config MFD_ATMEL_HLCDC
>  	tristate "Atmel HLCDC (High-end LCD Controller)"
>  	select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 5eaa6465d..b280d0a 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -199,6 +199,8 @@ obj-$(CONFIG_MFD_DLN2)		+= dln2.o
>  obj-$(CONFIG_MFD_RT5033)	+= rt5033.o
>  obj-$(CONFIG_MFD_SKY81452)	+= sky81452.o
>  
> +obj-$(CONFIG_MFD_SUNXI_ADC)	+= sunxi-gpadc-mfd.o
> +
>  intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
>  intel-soc-pmic-$(CONFIG_INTEL_PMC_IPC)	+= intel_soc_pmic_bxtwc.o
>  obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
> diff --git a/drivers/mfd/sunxi-gpadc-mfd.c b/drivers/mfd/sunxi-gpadc-mfd.c
> new file mode 100644
> index 0000000..710e297
> --- /dev/null
> +++ b/drivers/mfd/sunxi-gpadc-mfd.c
> @@ -0,0 +1,188 @@
> +#include <linux/interrupt.h>
> +#include <linux/regmap.h>
> +#include <linux/mfd/sunxi-gpadc-mfd.h>
> +#include <linux/mfd/core.h>
> +#include <linux/of_device.h>
> +#include <linux/of_irq.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +
> +#define SUNXI_IRQ_FIFO_DATA	0
> +#define SUNXI_IRQ_TEMP_DATA	1
> +
> +static struct resource adc_resources[] = {
> +	{
> +		.name	= "FIFO_DATA_PENDING",
> +		.start	= SUNXI_IRQ_FIFO_DATA,
> +		.end	= SUNXI_IRQ_FIFO_DATA,
> +		.flags	= IORESOURCE_IRQ,
> +	}, {
> +		.name	= "TEMP_DATA_PENDING",
> +		.start	= SUNXI_IRQ_TEMP_DATA,
> +		.end	= SUNXI_IRQ_TEMP_DATA,
> +		.flags	= IORESOURCE_IRQ,
> +	},
> +};
> +
> +static const struct regmap_irq sunxi_gpadc_mfd_regmap_irq[] = {
> +	REGMAP_IRQ_REG(SUNXI_IRQ_FIFO_DATA, 0, BIT(16)),
> +	REGMAP_IRQ_REG(SUNXI_IRQ_TEMP_DATA, 0, BIT(18)),
> +};
> +
> +static const struct regmap_irq_chip sunxi_gpadc_mfd_regmap_irq_chip = {
> +	.name = "sunxi_gpadc_mfd_irq_chip",
> +	.status_base = TP_INT_FIFOS,
> +	.ack_base = TP_INT_FIFOS,
> +	.mask_base = TP_INT_FIFOC,
> +	.init_ack_masked = true,
> +	.mask_invert = true,
> +	.irqs = sunxi_gpadc_mfd_regmap_irq,
> +	.num_irqs = ARRAY_SIZE(sunxi_gpadc_mfd_regmap_irq),
> +	.num_regs = 1,
> +};
> +
> +static struct mfd_cell sun4i_gpadc_mfd_cells[] = {
> +	{
> +		.name	= "sun4i-a10-gpadc-iio",
> +		.resources = adc_resources,
> +		.num_resources = ARRAY_SIZE(adc_resources),
> +	}, {
> +		.name = "iio_hwmon",
> +	}
> +};
> +
> +static struct mfd_cell sun5i_gpadc_mfd_cells[] = {
> +	{
> +		.name	= "sun5i-a13-gpadc-iio",
> +		.resources = adc_resources,
> +		.num_resources = ARRAY_SIZE(adc_resources),
> +	}, {
> +		.name = "iio_hwmon",
> +	},
> +};
> +
> +static struct mfd_cell sun6i_gpadc_mfd_cells[] = {
> +	{
> +		.name	= "sun6i-a31-gpadc-iio",
> +		.resources = adc_resources,
> +		.num_resources = ARRAY_SIZE(adc_resources),
> +	}, {
> +		.name = "iio_hwmon",
Interesting to probe this as part of the mfd as opposed to separately
describing it in the devicetree.
> +	},
> +};
> +
> +static const struct regmap_config sunxi_gpadc_mfd_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.fast_io = true,
> +};
> +
> +static int sunxi_gpadc_mfd_probe(struct platform_device *pdev)
> +{
> +	struct sunxi_gpadc_mfd_dev *sunxi_gpadc_mfd_dev = NULL;
> +	struct resource *mem = NULL;
> +	unsigned int irq;
> +	int ret;
> +
> +	sunxi_gpadc_mfd_dev = devm_kzalloc(&pdev->dev,
> +					   sizeof(*sunxi_gpadc_mfd_dev),
> +					   GFP_KERNEL);
> +	if (!sunxi_gpadc_mfd_dev)
> +		return -ENOMEM;
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	sunxi_gpadc_mfd_dev->regs = devm_ioremap_resource(&pdev->dev, mem);
> +	if (IS_ERR(sunxi_gpadc_mfd_dev->regs))
> +		return PTR_ERR(sunxi_gpadc_mfd_dev->regs);
> +
> +	sunxi_gpadc_mfd_dev->dev = &pdev->dev;
> +	dev_set_drvdata(sunxi_gpadc_mfd_dev->dev, sunxi_gpadc_mfd_dev);
> +
> +	sunxi_gpadc_mfd_dev->regmap =
> +		devm_regmap_init_mmio(sunxi_gpadc_mfd_dev->dev,
> +				      sunxi_gpadc_mfd_dev->regs,
> +				      &sunxi_gpadc_mfd_regmap_config);
> +	if (IS_ERR(sunxi_gpadc_mfd_dev->regmap)) {
> +		ret = PTR_ERR(sunxi_gpadc_mfd_dev->regmap);
> +		dev_err(&pdev->dev, "failed to init regmap: %d\n", ret);
> +		return ret;
> +	}
> +
> +	irq = platform_get_irq(pdev, 0);
> +	ret = regmap_add_irq_chip(sunxi_gpadc_mfd_dev->regmap, irq,
> +				  IRQF_ONESHOT, 0,
> +				  &sunxi_gpadc_mfd_regmap_irq_chip,
> +				  &sunxi_gpadc_mfd_dev->regmap_irqc);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to add irq chip: %d\n", ret);
> +		return ret;
> +	}
> +
> +	if (of_device_is_compatible(pdev->dev.of_node,
> +				    "allwinner,sun4i-a10-ts"))
> +		ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
> +				      sun4i_gpadc_mfd_cells,
> +				      ARRAY_SIZE(sun4i_gpadc_mfd_cells), NULL,
> +				      0, NULL);
> +	else if (of_device_is_compatible(pdev->dev.of_node,
> +					 "allwinner,sun5i-a13-ts"))
> +		ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
> +				      sun5i_gpadc_mfd_cells,
> +				      ARRAY_SIZE(sun5i_gpadc_mfd_cells), NULL,
> +				      0, NULL);
> +	else if (of_device_is_compatible(pdev->dev.of_node,
> +					 "allwinner,sun6i-a31-ts"))
> +		ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
> +				      sun6i_gpadc_mfd_cells,
> +				      ARRAY_SIZE(sun6i_gpadc_mfd_cells), NULL,
> +				      0, NULL);
> +
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to add MFD devices: %d\n", ret);
> +		regmap_del_irq_chip(irq, sunxi_gpadc_mfd_dev->regmap_irqc);
> +		mfd_remove_devices(&pdev->dev);
> +		return ret;
> +	}
> +
> +	dev_info(&pdev->dev, "successfully loaded\n");
> +
> +	return 0;
> +}
> +
> +static int sunxi_gpadc_mfd_remove(struct platform_device *pdev)
> +{
> +	struct sunxi_gpadc_mfd_dev *sunxi_gpadc_mfd_dev;
> +	unsigned int irq;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	mfd_remove_devices(&pdev->dev);
> +	sunxi_gpadc_mfd_dev = dev_get_drvdata(&pdev->dev);
> +	regmap_del_irq_chip(irq, sunxi_gpadc_mfd_dev->regmap_irqc);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id sunxi_gpadc_mfd_of_match[] = {
> +	{ .compatible = "allwinner,sun4i-a10-ts" },
> +	{ .compatible = "allwinner,sun5i-a13-ts" },
> +	{ .compatible = "allwinner,sun6i-a31-ts" },
> +	{ /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, sunxi_gpadc_mfd_of_match);
> +
> +static struct platform_driver sunxi_gpadc_mfd_driver = {
> +	.driver = {
> +		.name = "sunxi-adc-mfd",
> +		.of_match_table = of_match_ptr(sunxi_gpadc_mfd_of_match),
> +	},
> +	.probe = sunxi_gpadc_mfd_probe,
> +	.remove = sunxi_gpadc_mfd_remove,
> +};
> +
> +module_platform_driver(sunxi_gpadc_mfd_driver);
> +
> +MODULE_DESCRIPTION("ADC MFD core driver for sunxi platforms");
> +MODULE_AUTHOR("Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/sunxi-gpadc-mfd.h b/include/linux/mfd/sunxi-gpadc-mfd.h
> new file mode 100644
> index 0000000..341f8c3
> --- /dev/null
> +++ b/include/linux/mfd/sunxi-gpadc-mfd.h
> @@ -0,0 +1,14 @@
> +#ifndef __SUNXI_GPADC_MFD__H__
> +#define __SUNXI_GPADC_MFD__H__
> +
> +#define TP_INT_FIFOC            0x10
> +#define TP_INT_FIFOS            0x14
> +
> +struct sunxi_gpadc_mfd_dev {
> +	void __iomem			*regs;
> +	struct device			*dev;
> +	struct regmap			*regmap;
> +	struct regmap_irq_chip_data	*regmap_irqc;
> +};
> +
> +#endif
>