On Fri, May 6, 2016 at 2:10 PM, Christian Lamparter
<chunkeey@xxxxxxxxxxxxxx> wrote:
> From: Álvaro Fernández Rojas <noltari@xxxxxxxxx>
>
> This patch adds support for defining memory-mapped GPIOs which
> are compatible with the existing gpio-mmio interface. The generic
> library provides support for many memory-mapped GPIO controllers
> that are found in various on-board FPGA and ASIC solutions that
> are used to control board's switches, LEDs, chip-selects,
> Ethernet/USB PHY power, etc.
>
> For setting GPIO's there are three configurations:
> 1. single input/output register resource (named "dat"),
> 2. set/clear pair (named "set" and "clr"),
> 3. single output register resource and single input resource
> ("set" and dat").
>
> The configuration is detected by which resources are present.
> For the single output register, this drives a 1 by setting a bit
> and a zero by clearing a bit. For the set clr pair, this drives
> a 1 by setting a bit in the set register and clears it by setting
> a bit in the clear register. The configuration is detected by
> which resources are present.
>
> For setting the GPIO direction, there are three configurations:
> a. simple bidirectional GPIOs that requires no configuration.
> b. an output direction register (named "dirout")
> where a 1 bit indicates the GPIO is an output.
> c. an input direction register (named "dirin")
> where a 1 bit indicates the GPIO is an input.
>
> The first user for this binding is "wd,mbl-gpio".
Some (mostly) style issues below.
> @@ -569,6 +571,89 @@ static void __iomem *bgpio_map(struct platform_device *pdev,
> return devm_ioremap_resource(&pdev->dev, r);
> }
>
> +#ifdef CONFIG_OF
> +static int bgpio_basic_mmio_parse_dt(struct platform_device *pdev,
> + struct bgpio_pdata *pdata,
> + unsigned long *flags)
> +{
> + struct device *dev = &pdev->dev;
> + int err;
> +
> + pdata->base = -1;
+ empty line
> + /* If ngpio property is not specified, of_property_read_u32
> + * will return -EINVAL. In this case the number of GPIOs is
> + * automatically determined by the register width. Any
> + * other error of of_property_read_u32 is due bad data and
> + * needs to be dealt with.
Couple style issues:
/*
* First sentence starts here. func() are going with parens.
*/
> + */
> + err = of_property_read_u32(dev->of_node, "ngpio", &pdata->ngpio);
> + if (err && err != -EINVAL)
> + return err;
> +
> + if (of_device_is_big_endian(dev->of_node))
> + *flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;
> +
> + if (of_property_read_bool(dev->of_node, "unreadable-reg-set"))
> + *flags |= BGPIOF_UNREADABLE_REG_SET;
> +
> + if (of_property_read_bool(dev->of_node, "unreadable-reg-dir"))
> + *flags |= BGPIOF_UNREADABLE_REG_DIR;
> +
> + if (of_property_read_bool(dev->of_node, "big-endian-byte-order"))
> + *flags |= BGPIOF_BIG_ENDIAN;
> +
> + if (of_property_read_bool(dev->of_node, "read-output-reg-set"))
> + *flags |= BGPIOF_READ_OUTPUT_REG_SET;
> +
> + if (of_property_read_bool(dev->of_node, "no-output"))
> + *flags |= BGPIOF_NO_OUTPUT;
> + return 0;
> +}
> +
> +#define ADD_GPIO_OF(_name, _func) { .compatible = _name, .data = _func }
> +
> +static const struct of_device_id bgpio_of_match[] = {
> + ADD_GPIO_OF("wd,mbl-gpio", bgpio_basic_mmio_parse_dt),
> + { }
> +};
> +#undef ADD_GPIO_OF
> +MODULE_DEVICE_TABLE(of, bgpio_of_match);
> +
> +static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
> + unsigned long *flags)
> +{
> + const int (*parse_dt)(struct platform_device *,
> + struct bgpio_pdata *, unsigned long *);
> + const struct device_node *node = pdev->dev.of_node;
> + const struct of_device_id *of_id;
> + struct bgpio_pdata *pdata;
> + int err = -ENODEV;
(1)
> +
> + of_id = of_match_node(bgpio_of_match, node);
> + if (!of_id)
> + return NULL;
(2)
Why so?
> +
> + pdata = devm_kzalloc(&pdev->dev, sizeof(struct bgpio_pdata),
> + GFP_KERNEL);
> + if (!pdata)
> + return ERR_PTR(-ENOMEM);
> +
> + parse_dt = (const void *)of_id->data;
> + if (parse_dt)
> + err = parse_dt(pdev, pdata, flags);
> + if (err)
> + return ERR_PTR(err);
> +
> + return pdata;
> +}
> +#else
> +static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
> + unsigned long *flags)
> +{
> + return NULL;
> +}
> +#endif /* CONFIG_OF */
--
With Best Regards,
Andy Shevchenko
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