| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <0a1ab2b6-b4c5-44d7-abb4-ce1e9da7e477@gmail.com>
Date: Thu, 12 May 2016 19:26:32 +0900
From: Alexandre Courbot <gnurou@...il.com>
To: Christian Lamparter <chunkeey@...glemail.com>
Cc: <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
Álvaro Fernández Rojas <noltari@...il.com>,
Alexander Shiyan <shc_work@...l.ru>,
Alexandre Courbot <gnurou@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
Andy Shevchenko <andy.shevchenko@...il.com>,
Joachim Eastwood <manabian@...il.com>
Subject: Re: [PATCH v9 1/2] gpio: mmio: add DT support for memory-mapped GPIOs
On Wednesday, May 11, 2016 6:34:34 PM JST, Christian Lamparter wrote:
> From: Álvaro Fernández Rojas <noltari@...il.com>
>
> 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:
s/GPIO's/GPIOs
> 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.
The last sentence of this paragraph repeats for first one.
>
> 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".
>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
> Signed-off-by: Christian Lamparter <chunkeey@...glemail.com>
> ---
> drivers/gpio/gpio-mmio.c | 68
> ++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 66 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
> index 6c1cb3b..f72e40e 100644
> --- a/drivers/gpio/gpio-mmio.c
> +++ b/drivers/gpio/gpio-mmio.c
> @@ -61,6 +61,8 @@ o ` ~~~~\___/~~~~
> ` controller in FPGA is ,.`
> #include <linux/bitops.h>
> #include <linux/platform_device.h>
> #include <linux/mod_devicetable.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>
> static void bgpio_write8(void __iomem *reg, unsigned long data)
> {
> @@ -569,6 +571,58 @@ 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;
> +
> + pdata->base = -1;
> +
> + if (of_property_read_bool(dev->of_node, "no-output"))
> + *flags |= BGPIOF_NO_OUTPUT;
I don't think it is a good idea to add "generic" properties. Whether a
controller is capable of output or not should be determined by its
compatible string only, and not a vague property.
> +
> + return 0;
> +}
> +
> +static const struct of_device_id bgpio_of_match[] = {
> + { .compatible = "wd,mbl-gpio", .data = bgpio_basic_mmio_parse_dt },
Mmm cannot you determine whether your controller is capable of output or
not just from the compatible property here? If so, the
bgpio_basic_mmio_parse_dt seems to be unneeded. If not, then this is
dependent on the wd,mbl-gpio binding and should be renamed accordingly.
> + { }
> +};
> +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 *);
> + struct bgpio_pdata *pdata;
> + int err;
> +
> + parse_dt = of_device_get_match_data(&pdev->dev);
> + if (!parse_dt)
> + return NULL;
> +
> + pdata = devm_kzalloc(&pdev->dev, sizeof(struct bgpio_pdata),
> + GFP_KERNEL);
> + if (!pdata)
> + return ERR_PTR(-ENOMEM);
> +
> + 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 */
> +
> static int bgpio_pdev_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -579,10 +633,19 @@ static int bgpio_pdev_probe(struct
> platform_device *pdev)
> void __iomem *dirout;
> void __iomem *dirin;
> unsigned long sz;
> - unsigned long flags = pdev->id_entry->driver_data;
> + unsigned long flags = 0;
> int err;
> struct gpio_chip *gc;
> - struct bgpio_pdata *pdata = dev_get_platdata(dev);
> + struct bgpio_pdata *pdata;
> +
> + pdata = bgpio_parse_dt(pdev, &flags);
> + if (IS_ERR(pdata))
> + return PTR_ERR(pdata);
> +
> + if (!pdata) {
> + pdata = dev_get_platdata(dev);
> + flags = pdev->id_entry->driver_data;
> + }
>
> r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
> if (!r)
> @@ -646,6 +709,7 @@ MODULE_DEVICE_TABLE(platform, bgpio_id_table);
> static struct platform_driver bgpio_driver = {
> .driver = {
> .name = "basic-mmio-gpio",
> + .of_match_table = of_match_ptr(bgpio_of_match),
> },
> .id_table = bgpio_id_table,
> .probe = bgpio_pdev_probe,
It seems to me that this patch does two things:
1) Add code to support device tree lookup
2) Add support for "wd,mbl-gpio".
If true, these two things should be in their own patches. You should also
have another patch that adds the DT bindings for "wd,mbl-gpio", so I would
do things in that order:
1/3: DT support for basic-mmio-gpio
2/3: DT bindings for "wd,mbl-gpio" (and have them validated by the DT
people - e.g. do you really need a "reg" property or is it here just to fit
with what bgpio_pdev_probe expects? More about this on 2/2)
3/3: Support for "wd,mbl-gpio" in basic-mmio-gpio
Powered by blists - more mailing lists