On Tuesday 02 September 2014 20:12:15 Pankaj Dubey wrote: > Currently a syscon entity can only be registered directly through a > platform device that binds to a dedicated syscon driver. However in > certain cases it is required to bind a device with it's dedicated > driver rather than binding with syscon driver. > > 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 platform driver, and > allows to create syscon objects first time when it is required by > calling of syscon_regmap_lookup_by APIs and keeps a list of such syscon > objects along with syscon provider device_nodes and regmap handles. > > Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx> > Signed-off-by: Tomasz Figa <t.figa@xxxxxxxxxxx> > --- > V1 of this patchset [1] and related discussion can be found here [1]. > > Changes since v1: > - Removed of_syscon_unregister function. > - Modified of_syscon_register function and it will be used by syscon.c > to create syscon objects whenever required. > - Removed platform device support from syscon. > - Removed syscon_regmap_lookup_by_pdevname API support. > - As there are significant changes w.r.t patchset v1, I am taking over > author for this patchset from Tomasz Figa. Note that you got the Signed-off-by: list wrong, you should never have any people listed as Signed-off-by after your own name, and they should be listed before your name only when you are forwarding their patches. > Note: Current kernel has clps711x user of syscon_regmap_lookup_by_pdevname and > will be broken after this patch. As per discussion over here [1], patches > for making these drivers DT based are ready and once that is done they can use > syscon_regmap_lookup_by_phandle or syscon_regmap_lookup_by_compatible. > > [1]: https://lkml.org/lkml/2014/8/22/81 Adding Alexander Shiyan to Cc here, so we can make sure this is well coordinated. I'm also adding Michal Simek, since here was involved in earlier discussions about doing this. > drivers/mfd/syscon.c | 143 +++++++++++++------------------------------- > include/linux/mfd/syscon.h | 1 + > 2 files changed, 44 insertions(+), 100 deletions(-) I certainly like the diffstat ;-) > struct syscon { > + struct device_node *np; > struct regmap *regmap; > + struct list_head list; > }; Right > @@ -68,27 +72,6 @@ struct regmap *syscon_regmap_lookup_by_compatible(const char *s) > } > EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); > > -static int syscon_match_pdevname(struct device *dev, void *data) > -{ > - return !strcmp(dev_name(dev), (const char *)data); > -} > - > -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); > - > - return syscon->regmap; > -} > -EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname); I think this can actually be left intact if that helps with clps71xx. It could be done in a hacky way using bus_find_device_by_name() to keep it simple, or in a somewhat nicer way by keeping the syscon platform_driver around for the non-DT case. > + regmap = regmap_init_mmio(NULL, base, &syscon_regmap_config); > + if (IS_ERR(regmap)) { > + pr_err("regmap init failed\n"); > + return ERR_CAST(regmap); > + } The last time I looked over this code, I think it was not safe to call regmap_init_mmio() with a NULL device pointer, and we decided that should be fixed. Have you checked whether it is ok now? Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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