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SubjectRe: [PATCH] mfd: syscon: Decouple syscon interface from syscon devices
On Fri, 22 Aug 2014, Pankaj Dubey wrote:

> From: Tomasz Figa <t.figa@samsung.com>
>
> Currently a syscon entity can be only registered directly through a
> platform device that binds to a dedicated driver. However in certain use
> cases it is desirable to make a device used with another driver a syscon
> interface provider. For example, certain SoCs (e.g. Exynos) contain
> system controller blocks which perform various functions such as power
> domain control, CPU power management, low power mode control, but in
> addition contain certain IP integration glue, such as various signal
> masks, coprocessor power control, etc. In such case, there is a need to
> have a dedicated driver for such system controller but also share
> registers with other drivers. The latter is where the syscon interface
> is helpful.
>
> This patch decouples syscon object from syscon driver, so that it can be
> registered from any driver in addition to the original "syscon" platform
> driver.
>
> Signed-off-by: Tomasz Figa <t.figa@samsung.com>
> Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
> ---
>
> RFC patch [1] was posted by Tomasz Figa. This patch addresses some of
> comments given by Arnd to RFC patch, and further decouples syscon from
> device model. It also gives flexibility of registering with syscon at
> early stage using device_node object.

It would be helpful if Arnd gave this revision his blessing (Ack).

> [1]: https://lkml.org/lkml/2014/6/17/331
>
> drivers/mfd/syscon.c | 112 ++++++++++++++++++++++++++++----------------
> include/linux/mfd/syscon.h | 14 ++++++
> 2 files changed, 86 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index ca15878..a91db30 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -14,6 +14,7 @@

[...]

> struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
> {
> - struct device *dev;
> - struct syscon *syscon;
> -
> - dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
> - syscon_match_pdevname);
> - if (!dev)
> - return ERR_PTR(-EPROBE_DEFER);
> -
> - syscon = dev_get_drvdata(dev);
> + struct syscon *entry, *syscon = NULL;
> + struct platform_device *pdev = NULL;
> +
> + spin_lock(&syscon_list_slock);
> + list_for_each_entry(entry, &syscon_list, list) {
> + pdev = of_find_device_by_node(entry->np);

White space error.

Did you run this through checkpatch.pl?

> + if (pdev && !strcmp(dev_name(&pdev->dev), s)) {
> + syscon = entry;
> + break;
> + }
> + }
> + spin_unlock(&syscon_list_slock);
>
> - return syscon->regmap;
> + return syscon ? syscon->regmap : ERR_PTR(-EPROBE_DEFER);
> }
> EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);

[...]

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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