On Wed, Sep 17, 2014 at 12:01:50PM +0530, Pankaj Dubey wrote: > Currently a syscon entity can be only registered directly through a > platform device that binds to a dedicated syscon 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. > > In case of DT based platforms, 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 keep > a list of such syscon objects along with syscon provider device_nodes > and regmap handles. > > For non-DT based platforms, this patch keeps syscon platform driver > structure where is can be probed and such non-DT based drivers can use > syscon_regmap_lookup_by_pdev API and get access to regmap handles. > Once all users of "syscon_regmap_lookup_by_pdev" migrated to DT based, > we can completly remove platform driver of syscon, and keep only helper > functions to get regmap handles. > > Suggested-by: Arnd Bergmann <arnd@xxxxxxxx> > Suggested-by: Tomasz Figa <tomasz.figa@xxxxxxxxx> > Tested-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx> > Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx> > --- > V2 of this patchset and related discussion can be found here [1]. > > Changes since v2: > - Added back platform device support from syscon, with one change that > syscon will not be probed for DT based platform. > - Added back syscon_regmap_lookup_by_pdevname API so that non-DT base > users of syscon will not be broken. > - Removed unwanted change in syscon.h. > - Modified Signed-off-by list, added Suggested-by of Tomasz Figa and > Arnd Bergmann. > - Added Tested-by of Vivek Gautam for testing on Exynos platform. > > 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. > > [1]: https://lkml.org/lkml/2014/9/2/299 > > drivers/mfd/syscon.c | 78 ++++++++++++++++++++++++++++++++++++-------------- > 1 file changed, 57 insertions(+), 21 deletions(-) > > diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c > index ca15878..4a4bad9 100644 > --- a/drivers/mfd/syscon.c > +++ b/drivers/mfd/syscon.c > @@ -15,40 +15,49 @@ > #include <linux/err.h> > #include <linux/io.h> > #include <linux/module.h> > +#include <linux/list.h> > #include <linux/of.h> > #include <linux/of_address.h> > -#include <linux/of_platform.h> > #include <linux/platform_data/syscon.h> > #include <linux/platform_device.h> > #include <linux/regmap.h> > #include <linux/mfd/syscon.h> > +#include <linux/slab.h> > > static struct platform_driver syscon_driver; > > +static DEFINE_SPINLOCK(syscon_list_slock); > +static LIST_HEAD(syscon_list); > + > struct syscon { > + struct device_node *np; > struct regmap *regmap; > + struct list_head list; > }; > > -static int syscon_match_node(struct device *dev, void *data) > -{ > - struct device_node *dn = data; > - > - return (dev->of_node == dn) ? 1 : 0; > -} > +static struct syscon *of_syscon_register(struct device_node *np); > > struct regmap *syscon_node_to_regmap(struct device_node *np) > { > - struct syscon *syscon; > - struct device *dev; > + struct syscon *entry, *syscon = NULL; > > - dev = driver_find_device(&syscon_driver.driver, NULL, np, > - syscon_match_node); > - if (!dev) > - return ERR_PTR(-EPROBE_DEFER); > + spin_lock(&syscon_list_slock); > > - syscon = dev_get_drvdata(dev); > + list_for_each_entry(entry, &syscon_list, list) > + if (entry->np == np) { > + syscon = entry; > + break; > + } > > - return syscon->regmap; > + spin_unlock(&syscon_list_slock); > + > + if (!syscon) > + syscon = of_syscon_register(np); > + > + if (!IS_ERR(syscon)) > + return syscon->regmap; > + > + return ERR_CAST(syscon); > } > EXPORT_SYMBOL_GPL(syscon_node_to_regmap); > > @@ -110,17 +119,45 @@ struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, > } > EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); > > -static const struct of_device_id of_syscon_match[] = { > - { .compatible = "syscon", }, > - { }, > -}; > - > static struct regmap_config syscon_regmap_config = { > .reg_bits = 32, > .val_bits = 32, > .reg_stride = 4, > }; > > +static struct syscon *of_syscon_register(struct device_node *np) > +{ > + struct syscon *syscon; > + struct regmap *regmap; > + void __iomem *base; > + > + if (!of_device_is_compatible(np, "syscon")) > + return ERR_PTR(-EINVAL); > + > + syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); > + if (!syscon) > + return ERR_PTR(-ENOMEM); > + > + base = of_iomap(np, 0); > + if (!base) > + return ERR_PTR(-ENOMEM); > + > + regmap = regmap_init_mmio(NULL, base, &syscon_regmap_config); Does a NULL device pointer work? I just tested on MX6SX SDB board and it seemed crashed at here in regmap_init function. Regards Dong Aisheng > + if (IS_ERR(regmap)) { > + pr_err("regmap init failed\n"); > + return ERR_CAST(regmap); > + } > + > + syscon->regmap = regmap; > + syscon->np = np; > + > + spin_lock(&syscon_list_slock); > + list_add_tail(&syscon->list, &syscon_list); > + spin_unlock(&syscon_list_slock); > + > + return syscon; > +} > + > static int syscon_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > @@ -167,7 +204,6 @@ static struct platform_driver syscon_driver = { > .driver = { > .name = "syscon", > .owner = THIS_MODULE, > - .of_match_table = of_syscon_match, > }, > .probe = syscon_probe, > .id_table = syscon_ids, > -- > 1.7.9.5 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- 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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