Re: [PATCH v2] iio: adc: rockchip_saradc: add support for rk3066-tsadc variant

[Hartmut Knaack]

Heiko Stübner schrieb, Am 11.09.2014 00:22:
> Older Rockchip SoCs, at least the rk3066, used a slightly modified saradc
> for temperature measurements. This so called tsadc does not contain any
> active parts like temperature interrupts and only supports polling the
> current temperature. The returned voltage can then be converted by a
> suitable thermal driver to and actual temperature and used for thermal
> handling.
> 
Looking over it again, I have a two more comments inline.
> Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
> ---
> changes since v1:
> - use GENMASK instead of creating the mask manually
>   as suggested by Hartmut Knaack
> 
> I've also opted for simply keeping the indent mismatch in
> struct rockchip_saradc, as I don't think it's worth the churn
> it produces
> 
>  .../bindings/iio/adc/rockchip-saradc.txt           |  2 +-
>  drivers/iio/adc/rockchip_saradc.c                  | 62 +++++++++++++++++-----
>  2 files changed, 50 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt b/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
> index 5d3ec1d..a9a5fe1 100644
> --- a/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
> +++ b/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
> @@ -1,7 +1,7 @@
>  Rockchip Successive Approximation Register (SAR) A/D Converter bindings
>  
>  Required properties:
> -- compatible: Should be "rockchip,saradc"
> +- compatible: Should be "rockchip,saradc" or "rockchip,rk3066-tsadc"
>  - reg: physical base address of the controller and length of memory mapped
>         region.
>  - interrupts: The interrupt number to the cpu. The interrupt specifier format
> diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
> index e074a0b..99200b7 100644
> --- a/drivers/iio/adc/rockchip_saradc.c
> +++ b/drivers/iio/adc/rockchip_saradc.c
> @@ -18,13 +18,13 @@
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <linux/clk.h>
>  #include <linux/completion.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/iio/iio.h>
>  
>  #define SARADC_DATA			0x00
> -#define SARADC_DATA_MASK		0x3ff
>  
>  #define SARADC_STAS			0x04
>  #define SARADC_STAS_BUSY		BIT(0)
> @@ -38,15 +38,22 @@
>  #define SARADC_DLY_PU_SOC		0x0c
>  #define SARADC_DLY_PU_SOC_MASK		0x3f
>  
> -#define SARADC_BITS			10
>  #define SARADC_TIMEOUT			msecs_to_jiffies(100)
>  
> +struct rockchip_saradc_data {
> +	int				num_bits;
> +	const struct iio_chan_spec	*channels;
> +	int				num_channels;
> +	unsigned long			clk_rate;
> +};
> +
>  struct rockchip_saradc {
>  	void __iomem		*regs;
>  	struct clk		*pclk;
>  	struct clk		*clk;
>  	struct completion	completion;
>  	struct regulator	*vref;
> +	const struct rockchip_saradc_data *data;
>  	u16			last_val;
>  };
>  
> @@ -90,7 +97,7 @@ static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
>  		}
>  
>  		*val = ret / 1000;
> -		*val2 = SARADC_BITS;
> +		*val2 = info->data->num_bits;
>  		return IIO_VAL_FRACTIONAL_LOG2;
>  	default:
>  		return -EINVAL;
> @@ -103,7 +110,7 @@ static irqreturn_t rockchip_saradc_isr(int irq, void *dev_id)
>  
>  	/* Read value */
>  	info->last_val = readl_relaxed(info->regs + SARADC_DATA);
> -	info->last_val &= SARADC_DATA_MASK;
> +	info->last_val &= GENMASK(info->data->num_bits - 1, 0);
>  
>  	/* Clear irq & power down adc */
>  	writel_relaxed(0, info->regs + SARADC_CTRL);
> @@ -133,12 +140,44 @@ static const struct iio_chan_spec rockchip_saradc_iio_channels[] = {
>  	ADC_CHANNEL(2, "adc2"),
>  };
>  
> +static const struct rockchip_saradc_data saradc_data = {
> +	.num_bits = 10,
> +	.channels = rockchip_saradc_iio_channels,
> +	.num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels),
> +	.clk_rate = 1000000,
> +};
> +
> +static const struct iio_chan_spec rockchip_rk3066_tsadc_iio_channels[] = {
> +	ADC_CHANNEL(0, "adc0"),
> +	ADC_CHANNEL(1, "adc1"),
> +};
> +
> +static const struct rockchip_saradc_data rk3066_tsadc_data = {
> +	.num_bits = 12,
> +	.channels = rockchip_rk3066_tsadc_iio_channels,
> +	.num_channels = ARRAY_SIZE(rockchip_rk3066_tsadc_iio_channels),
> +	.clk_rate = 50000,
> +};
> +
> +static const struct of_device_id rockchip_saradc_match[] = {
> +	{
> +		.compatible = "rockchip,saradc",
> +		.data = &saradc_data,
> +	}, {
> +		.compatible = "rockchip,rk3066-tsadc",
> +		.data = &rk3066_tsadc_data,
> +	},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, rockchip_saradc_match);
> +
>  static int rockchip_saradc_probe(struct platform_device *pdev)
>  {
>  	struct rockchip_saradc *info = NULL;
>  	struct device_node *np = pdev->dev.of_node;
>  	struct iio_dev *indio_dev = NULL;
>  	struct resource	*mem;
> +	const struct of_device_id *match;
>  	int ret;
>  	int irq;
>  
> @@ -152,6 +191,9 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
>  	}
>  	info = iio_priv(indio_dev);
>  
> +	match = of_match_device(rockchip_saradc_match, &pdev->dev);
Is it 100% safe to go on without checking match for validity?
> +	info->data = match->data;
> +
>  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	info->regs = devm_ioremap_resource(&pdev->dev, mem);
>  	if (IS_ERR(info->regs))
> @@ -195,7 +237,7 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
>  	 * Use a default of 1MHz for the converter clock.
>  	 * This may become user-configurable in the future.
>  	 */
This comment becomes invalid and should be adjusted or droped.
> -	ret = clk_set_rate(info->clk, 1000000);
> +	ret = clk_set_rate(info->clk, info->data->clk_rate);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "failed to set adc clk rate, %d\n", ret);
>  		return ret;
> @@ -227,8 +269,8 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
>  	indio_dev->info = &rockchip_saradc_iio_info;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  
> -	indio_dev->channels = rockchip_saradc_iio_channels;
> -	indio_dev->num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels);
> +	indio_dev->channels = info->data->channels;
> +	indio_dev->num_channels = info->data->num_channels;
>  
>  	ret = iio_device_register(indio_dev);
>  	if (ret)
> @@ -296,12 +338,6 @@ static int rockchip_saradc_resume(struct device *dev)
>  static SIMPLE_DEV_PM_OPS(rockchip_saradc_pm_ops,
>  			 rockchip_saradc_suspend, rockchip_saradc_resume);
>  
> -static const struct of_device_id rockchip_saradc_match[] = {
> -	{ .compatible = "rockchip,saradc" },
> -	{},
> -};
> -MODULE_DEVICE_TABLE(of, rockchip_saradc_match);
> -
>  static struct platform_driver rockchip_saradc_driver = {
>  	.probe		= rockchip_saradc_probe,
>  	.remove		= rockchip_saradc_remove,
> 

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