Re: [PATCH 1/3] mfd: fsl imx25 Touchscreen ADC driver

[Markus Pargmann <mpa-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

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Hi Fabio,

On Thu, Feb 20, 2014 at 02:17:33PM -0300, Fabio Estevam wrote:
> Hi Markus,
> 
> On Thu, Feb 20, 2014 at 1:21 PM, Markus Pargmann <mpa-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> wrote:
> > This is the core driver for imx25 touchscreen/adc driver. The module
> > has one shared ADC and two different conversion queues which use the
> > ADC. The two queues are identical. Both can be used for general purpose
> > ADC but one is meant to be used for touchscreens.
> >
> > This driver is the core which manages the central components and
> > registers of the TSC/ADC unit. It manages the IRQs and forwards them to
> > the correct components.
> >
> > Signed-off-by: Markus Pargmann <mpa-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> 
> That's great :-) Nice work!

Thanks :)

> > ---
> >  .../devicetree/bindings/mfd/fsl-imx25-tsadc.txt    |  46 ++++
> >  drivers/mfd/Kconfig                                |   9 +
> >  drivers/mfd/Makefile                               |   2 +
> >  drivers/mfd/fsl-imx25-tsadc.c                      | 234 +++++++++++++++++++++
> >  include/linux/mfd/imx25-tsadc.h                    | 138 ++++++++++++
> >  5 files changed, 429 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/mfd/fsl-imx25-tsadc.txt
> >  create mode 100644 drivers/mfd/fsl-imx25-tsadc.c
> >  create mode 100644 include/linux/mfd/imx25-tsadc.h
> >
> > diff --git a/Documentation/devicetree/bindings/mfd/fsl-imx25-tsadc.txt b/Documentation/devicetree/bindings/mfd/fsl-imx25-tsadc.txt
> > new file mode 100644
> > index 0000000..a857af0e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mfd/fsl-imx25-tsadc.txt
> > @@ -0,0 +1,46 @@
> > +Freescale mx25 ADC/TSC multifunction device
> > +
> > +This device combines two general purpose conversion queues one used for general
> > +ADC and the other used for touchscreens.
> > +
> > +Required properties:
> > + - compatible: Should be "fsl,imx25-tsadc".
> > + - reg: Memory range of the device.
> > + - interrupts: Interrupt for this device as described in
> > +   interrupts/interrupts.txt
> > + - clocks: An 'ipg' clock defined as described in clocks/clock.txt
> > + - interrupt-controller: This device is an interrupt controller. It controls
> > +   the interrupts of both conversion queues.
> > + - #interrupt-cells: Should be '<1>'.
> > + - #address-cells: Should be '<1>'.
> > + - #size-cells: Should be '<1>'.
> > + - ranges
> > +
> > +This device includes two conversion queues which can be added as subnodes.
> > +The first queue is for the touchscreen, the second for general purpose ADC.
> > +
> > +Example:
> > +       tscadc: tscadc@50030000 {
> > +               compatible = "fsl,imx25-tsadc";
> > +               reg = <0x50030000 0xc>;
> > +               interrupts = <46>;
> > +               clocks = <&clks 119>;
> > +               clock-names = "ipg";
> > +               interrupt-controller;
> > +               #interrupt-cells = <1>;
> > +               #address-cells = <1>;
> > +               #size-cells = <1>;
> > +               ranges;
> > +
> > +               tsc: tcq@50030400 {
> > +                       compatible = "fsl,imx25-tcq";
> > +                       reg = <0x50030400 0x60>;
> > +                       ...
> > +               };
> > +
> > +               adc: gcq@50030800 {
> > +                       compatible = "fsl,imx25-gcq";
> > +                       reg = <0x50030800 0x60>;
> > +                       ...
> > +               };
> > +       };
> 
> The meaning of 'tcq' and 'gcq' acronyms are not obvious. Could they be
> written more explicitily?

I assume you mean the node names? Perhaps something like 'adcqueue'?

> 
> Also, what does the '...' mean?
> 
> > +static int mx25_tsadc_domain_map(struct irq_domain *d, unsigned int irq,
> > +                            irq_hw_number_t hwirq)
> > +{
> > +       struct mx25_tsadc_priv *priv = d->host_data;
> > +
> > +       irq_set_chip_data(irq, priv);
> > +       irq_set_chip_and_handler(irq, &mx25_tsadc_irq_chip,
> > +                                handle_level_irq);
> > +
> > +#ifdef CONFIG_ARM
> > +       set_irq_flags(irq, IRQF_VALID);
> > +#else
> > +       irq_set_noprobe(irq);
> > +#endif
> 
> Do we really need these ifdef's? Can't we just assume that CONFIG_ARM
> is always selected for this driver?

Yes right, this is not necessary here.

> 
> > +static int mx25_tsadc_probe(struct platform_device *pdev)
> > +{
> > +       struct device *dev = &pdev->dev;
> > +       struct device_node *np = dev->of_node;
> > +       struct mx25_tsadc_priv *priv;
> > +       struct resource *iores;
> > +       int ret;
> > +       void __iomem *iomem;
> > +
> > +       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > +       if (!priv)
> > +               return -ENOMEM;
> > +
> > +       iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +       iomem = devm_ioremap_resource(dev, iores);
> > +       if (IS_ERR(iomem)) {
> > +               dev_err(dev, "Failed to remap iomem\n");
> > +               return PTR_ERR(iomem);
> > +       }
> > +
> > +       priv->regs = regmap_init_mmio(dev, iomem, &mx25_tsadc);
> > +       if (IS_ERR(priv->regs)) {
> > +               dev_err(dev, "Failed to initialize regmap\n");
> > +               return PTR_ERR(priv->regs);
> > +       }
> > +
> > +       priv->clk = devm_clk_get(dev, "ipg");
> > +       if (IS_ERR(priv->clk)) {
> > +               dev_err(dev, "Failed to get ipg clock\n");
> > +               return PTR_ERR(priv->clk);
> > +       }
> > +
> > +       /* Enable clock and reset the component */
> > +       regmap_update_bits(priv->regs, MX25_TSC_TGCR, MX25_TGCR_CLK_EN,
> > +                       MX25_TGCR_CLK_EN);
> > +       regmap_update_bits(priv->regs, MX25_TSC_TGCR, MX25_TGCR_TSC_RST,
> > +                       MX25_TGCR_TSC_RST);
> > +
> > +       /* Setup powersaving mode, but enable internal reference voltage */
> > +       regmap_update_bits(priv->regs, MX25_TSC_TGCR, MX25_TGCR_POWERMODE_MASK,
> > +                       MX25_TGCR_POWERMODE_SAVE);
> > +       regmap_update_bits(priv->regs, MX25_TSC_TGCR, MX25_TGCR_INTREFEN,
> > +                       MX25_TGCR_INTREFEN);
> > +
> > +       ret = mx25_tsadc_setup_irq(pdev, priv);
> > +       if (ret) {
> > +               dev_err(dev, "Failed to setup irqs\n");
> > +               return ret;
> > +       }
> > +
> > +       platform_set_drvdata(pdev, priv);
> > +
> > +       of_platform_populate(np, NULL, NULL, dev);
> > +
> > +       dev_info(dev, "i.MX25/25 Touchscreen and ADC core driver loaded\n");
> 
> You could remove the double '25/25'.

Yes, fixed.

> 
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct of_device_id mx25_tsadc_ids[] = {
> > +       { .compatible = "fsl,imx25-tsadc", },
> > +       { /* Sentinel */ }
> > +};
> > +
> > +static struct platform_driver mx25_tsadc_driver = {
> > +       .driver         = {
> > +               .name   = "mx25-tsadc",
> > +               .owner  = THIS_MODULE,
> > +               .of_match_table = mx25_tsadc_ids,
> > +       },
> > +       .probe          = mx25_tsadc_probe,
> > +};
> > +module_platform_driver(mx25_tsadc_driver);
> > +
> > +MODULE_DESCRIPTION("MFD for ADC/TSC for Freescale mx25");
> > +MODULE_AUTHOR("Markus Pargmann <mpa-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>");
> > +MODULE_LICENSE("GPL v2");
> 
> MODULE_ALIAS() as well?

I am not sure if this is necessary, but I added
MODULE_ALIAS("platform:mx25-tsadc")

Thanks,

Markus

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