Re: [PATCH v3 17/47] mfd: ti_am335x_tscadc: Use driver data

[Lee Jones <lee.jones@linaro.org>]

On Wed, 15 Sep 2021, Miquel Raynal wrote:

> So far every sub-cell parameter in this driver was hardcoded: cell name,
> cell compatible, specific clock name and desired clock frequency.
> 
> As we are about to introduce support for ADC1/magnetic reader, we need a
> bit of flexibility. Let's add a driver data structure which will contain
> these information.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  drivers/mfd/ti_am335x_tscadc.c       | 25 +++++++++++++++++++------
>  include/linux/mfd/ti_am335x_tscadc.h |  9 +++++++++
>  2 files changed, 28 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
> index ba821109e98b..fbc8e338188a 100644
> --- a/drivers/mfd/ti_am335x_tscadc.c
> +++ b/drivers/mfd/ti_am335x_tscadc.c
> @@ -137,6 +137,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> +	tscadc->data = of_device_get_match_data(&pdev->dev);
> +
>  	node = of_get_child_by_name(pdev->dev.of_node, "tsc");
>  	of_property_read_u32(node, "ti,wires", &tsc_wires);
>  	of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
> @@ -212,7 +214,7 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  		goto err_disable_clk;
>  	}
>  
> -	tscadc->clk_div = (clk_get_rate(clk) / ADC_CLK) - 1;
> +	tscadc->clk_div = (clk_get_rate(clk) / tscadc->data->target_clk_rate) - 1;
>  	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
>  
>  	/* Set the control register bits */
> @@ -241,8 +243,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	if (tsc_wires > 0) {
>  		tscadc->tsc_cell = tscadc->used_cells;
>  		cell = &tscadc->cells[tscadc->used_cells++];
> -		cell->name = "TI-am335x-tsc";
> -		cell->of_compatible = "ti,am3359-tsc";
> +		cell->name = tscadc->data->name_tscmag;
> +		cell->of_compatible = tscadc->data->compat_tscmag;
>  		cell->platform_data = &tscadc;
>  		cell->pdata_size = sizeof(tscadc);
>  	}
> @@ -251,8 +253,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	if (adc_channels > 0) {
>  		tscadc->adc_cell = tscadc->used_cells;
>  		cell = &tscadc->cells[tscadc->used_cells++];
> -		cell->name = "TI-am335x-adc";
> -		cell->of_compatible = "ti,am3359-adc";
> +		cell->name = tscadc->data->name_adc;
> +		cell->of_compatible = tscadc->data->compat_adc;
>  		cell->platform_data = &tscadc;
>  		cell->pdata_size = sizeof(tscadc);
>  	}
> @@ -338,8 +340,19 @@ static int __maybe_unused tscadc_resume(struct device *dev)
>  
>  static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
>  
> +static const struct ti_tscadc_data tscdata = {
> +	.name_tscmag = "TI-am335x-tsc",
> +	.compat_tscmag = "ti,am3359-tsc",
> +	.name_adc = "TI-am335x-adc",
> +	.compat_adc = "ti,am3359-adc",
> +	.target_clk_rate = ADC_CLK,
> +};
> +
>  static const struct of_device_id ti_tscadc_dt_ids[] = {
> -	{ .compatible = "ti,am3359-tscadc", },
> +	{
> +		.compatible = "ti,am3359-tscadc",
> +		.data = &tscdata,
> +	},
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index ffc091b77633..0f581c15d95a 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -162,11 +162,20 @@
>  
>  #define TSCADC_CELLS		2
>  
> +struct ti_tscadc_data {
> +	char *name_tscmag;
> +	char *compat_tscmag;
> +	char *name_adc;
> +	char *compat_adc;

I think these names should be improved.

What is tscmag?

Does that represent both the Magnetic Reader and the Touchscreen?

If so, I'd prefer that you split them.  If not, I need more info.

For readability, I suggest;

  touchscreen_name
  touchscreen_compatible
  mag_reader_name
  mag_reader_compatible
  adc_name
  adc_compatible
  etc

What is a magnetic reader anyway?

Does it read the magnetic stripe on a payment card?

> +	unsigned int target_clk_rate;
> +};
> +
>  struct ti_tscadc_dev {
>  	struct device *dev;
>  	struct regmap *regmap;
>  	void __iomem *tscadc_base;
>  	phys_addr_t tscadc_phys_base;
> +	const struct ti_tscadc_data *data;
>  	int irq;
>  	int used_cells;	/* 1-2 */
>  	int tsc_wires;

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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