Re: [PATCH v3 35/47] mfd: ti_am335x_tscadc: Add ADC1/magnetic reader support

From: Lee Jones <lee.jones@linaro.org>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	Rob Herring <robh+dt@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	bcousson@baylibre.com, Tony Lindgren <tony@atomide.com>,
	linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-omap@vger.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Lokesh Vutla <lokeshvutla@ti.com>,
	Tero Kristo <kristo@kernel.org>,
	Ryan Barnett <ryan.barnett@collins.com>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Jason Reeder <jreeder@ti.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: Re: [PATCH v3 35/47] mfd: ti_am335x_tscadc: Add ADC1/magnetic reader support
Date: Wed, 22 Sep 2021 17:00:20 +0100	[thread overview]
Message-ID: <YUtTFEv1YFOMeuEb@google.com> (raw)
In-Reply-To: <20210915155908.476767-36-miquel.raynal@bootlin.com>

On Wed, 15 Sep 2021, Miquel Raynal wrote:

> Introduce a new compatible that has another set of driver data,
> targeting am437x SoCs with a magnetic reader instead of the
> touchscreen and a more featureful set of registers.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  drivers/mfd/ti_am335x_tscadc.c       | 41 ++++++++++++++++++++++++----
>  include/linux/mfd/ti_am335x_tscadc.h |  7 +++++
>  2 files changed, 42 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
> index 65c0fa735a71..155a8ed879b3 100644
> --- a/drivers/mfd/ti_am335x_tscadc.c
> +++ b/drivers/mfd/ti_am335x_tscadc.c
> @@ -121,11 +121,11 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	struct mfd_cell *cell;
>  	struct property *prop;
>  	const __be32 *cur;
> -	bool use_tsc = false;
> +	bool use_tsc = false, use_mag = false;
>  	u32 val;
>  	int err;
>  	int tscmag_wires = 0, adc_channels = 0, cell_idx = 0, total_channels;
> -	int readouts = 0;
> +	int readouts = 0, mag_tracks = 0;
>  
>  	/* Allocate memory for device */
>  	tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
> @@ -148,6 +148,16 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  		of_node_put(node);
>  		if (tscmag_wires)
>  			use_tsc = true;
> +	} else {
> +		/*
> +		 * When adding support for the magnetic reader, here is the
> +		 * place to look for the number of tracks used from device tree.
> +		 * Let's default to 0 for now.
> +		 */
> +		mag_tracks = 0;
> +		tscmag_wires = mag_tracks * 2;
> +		if (tscmag_wires)
> +			use_mag = true;
>  	}
>  
>  	node = of_get_child_by_name(pdev->dev.of_node, "adc");
> @@ -209,8 +219,9 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	 * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
>  	 * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
>  	 * am33xx ADCs expect to capture 200ksps.
> -	 * We need the ADC clocks to run at 3MHz.
> -	 * This frequency is valid since TSC_ADC_SS controller design
> +	 * am47xx ADCs expect to capture 867ksps.
> +	 * We need ADC clocks respectively running at 3MHz and 13MHz.
> +	 * These frequencies are valid since TSC_ADC_SS controller design
>  	 * assumes the OCP clock is at least 6x faster than the ADC clock.
>  	 */
>  	clk = devm_clk_get(&pdev->dev, NULL);
> @@ -238,6 +249,9 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  			else
>  				tscadc->ctrl |= CNTRLREG_TSC_4WIRE;
>  		}
> +	} else {
> +		tscadc->ctrl |= CNTRLREG_MAG_PREAMP_PWRDOWN |
> +				CNTRLREG_MAG_PREAMP_BYPASS;
>  	}
>  	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
>  
> @@ -246,7 +260,7 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	/* Enable the TSC module enable bit */
>  	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);
>  
> -	/* TSC Cell */
> +	/* TSC or MAG Cell */
>  	if (tscmag_wires > 0) {
>  		cell = &tscadc->cells[cell_idx++];
>  		cell->name = tscadc->data->name_tscmag;
> @@ -334,6 +348,7 @@ static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
>  
>  static const struct ti_tscadc_data tscdata = {
>  	.has_tsc = true,
> +	.has_mag = false,
>  	.name_tscmag = "TI-am335x-tsc",
>  	.compat_tscmag = "ti,am3359-tsc",
>  	.name_adc = "TI-am335x-adc",
> @@ -341,11 +356,25 @@ static const struct ti_tscadc_data tscdata = {
>  	.target_clk_rate = TSC_ADC_CLK,
>  };
>  
> +static const struct ti_tscadc_data magdata = {
> +	.has_tsc = false,
> +	.has_mag = true,

Why 2 bools?

Better to have a single u8:

  MODE_TOUCHSCREEN
  MODE_MAG_STRING
  MODE_NONE

> +	.name_tscmag = "TI-am43xx-mag",
> +	.compat_tscmag = "ti,am4372-mag",
> +	.name_adc = "TI-am43xx-adc",
> +	.compat_adc = "ti,am4372-adc",
> +	.target_clk_rate = MAG_ADC_CLK,
> +};
> +
>  static const struct of_device_id ti_tscadc_dt_ids[] = {
>  	{
>  		.compatible = "ti,am3359-tscadc",
>  		.data = &tscdata,
>  	},
> +	{
> +		.compatible = "ti,am4372-magadc",
> +		.data = &magdata,
> +	},
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
> @@ -363,6 +392,6 @@ static struct platform_driver ti_tscadc_driver = {
>  
>  module_platform_driver(ti_tscadc_driver);
>  
> -MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
> +MODULE_DESCRIPTION("TI touchscreen/magnetic reader/ADC MFD controller driver");

Magnetic what?  Tape, disk, stripe?

>  MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
>  MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index 467b3bec4335..9a412e6d764b 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -106,6 +106,11 @@
>  #define CNTRLREG_TSC_8WIRE	CNTRLREG_TSC_AFE_CTRL(3)
>  #define CNTRLREG_TSC_ENB	BIT(7)
>  
> +/*Control registers bitfields  for MAGADC IP */
> +#define CNTRLREG_MAGADCENB      BIT(0)
> +#define CNTRLREG_MAG_PREAMP_PWRDOWN BIT(5)
> +#define CNTRLREG_MAG_PREAMP_BYPASS  BIT(6)
> +
>  /* FIFO READ Register */
>  #define FIFOREAD_DATA_MASK	GENMASK(11, 0)
>  #define FIFOREAD_CHNLID_MASK	GENMASK(19, 16)
> @@ -119,6 +124,7 @@
>  #define CHARGE_STEP		0x11
>  
>  #define TSC_ADC_CLK		(3 * HZ_PER_MHZ)
> +#define MAG_ADC_CLK		(13 * HZ_PER_MHZ)
>  #define TOTAL_STEPS		16
>  #define TOTAL_CHANNELS		8
>  #define FIFO1_THRESHOLD		19
> @@ -141,6 +147,7 @@
>  
>  struct ti_tscadc_data {
>  	bool has_tsc;
> +	bool has_mag;
>  	char *name_tscmag;
>  	char *compat_tscmag;
>  	char *name_adc;

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