From mboxrd@z Thu Jan  1 00:00:00 1970
From: l.stach@pengutronix.de (Lucas Stach)
Date: Mon, 08 Jan 2018 11:51:32 +0100
Subject: [PATCH] soc: imx: gpc: de-register power domains only if
 initialized
In-Reply-To: <20180108102855.GA32635@b29396-OptiPlex-7040>
References: <20180107134905.15624-1-stefan@agner.ch>
 <20180108102855.GA32635@b29396-OptiPlex-7040>
Message-ID: <1515408692.12538.10.camel@pengutronix.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Am Montag, den 08.01.2018, 18:28 +0800 schrieb Dong Aisheng:
> On Sun, Jan 07, 2018 at 02:49:05PM +0100, Stefan Agner wrote:
> > If power domain information are missing in the device tree, no
> > power domains get initialized. However, imx_gpc_remove tries to
> > remove power domains always in the old DT binding case. Only
> > remove power domains when imx_gpc_probe initialized them in
> > first place.
> > 
> > Fixes: 721cabf6c660 ("soc: imx: move PGC handling to a new GPC
> > driver")
> > Cc: Lucas Stach <l.stach@pengutronix.de>
> > Signed-off-by: Stefan Agner <stefan@agner.ch>
> > ---
> > ?drivers/soc/imx/gpc.c | 10 +++++++++-
> > ?1 file changed, 9 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
> > index 53f7275d6cbd..62bb724726d9 100644
> > --- a/drivers/soc/imx/gpc.c
> > +++ b/drivers/soc/imx/gpc.c
> > @@ -470,13 +470,21 @@ static int imx_gpc_probe(struct
> > platform_device *pdev)
> > ?
> > ?static int imx_gpc_remove(struct platform_device *pdev)
> > ?{
> 
> What's the original purpose of imx_gpc_remove?
> ARM power domain can't be removed.

Why? As long as it stays powered on there is not reason why we wouldn't
be able to remove the driver.

> And why current imx_gpc_remove only remove domains for old DT but not
> for new ones?

With the new binding the power domains will be removed by the sub-
drivers for the domains.

> How about make it un-removable?
> e.g.

I don't see why this would be a good idea. Once more device-dependency
handling is in place we might need to unbind the power domains when the
regulator driver for the domain is unbound. Do you intend to make them
non-removable, too?

Regards,
Lucas

> diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
> index 47e7aa9..7fc6737 100644
> --- a/drivers/soc/imx/gpc.c
> +++ b/drivers/soc/imx/gpc.c
> @@ -454,36 +454,17 @@ static int imx_gpc_probe(struct platform_device
> *pdev)
> ????????return 0;
> ?}
> ?
> -static int imx_gpc_remove(struct platform_device *pdev)
> -{
> -???????int ret;
> -
> -???????/*
> -????????* If the old DT binding is used the toplevel driver needs to
> -????????* de-register the power domains
> -????????*/
> -???????if (!of_get_child_by_name(pdev->dev.of_node, "pgc")) {
> -???????????????of_genpd_del_provider(pdev->dev.of_node);
> -
> -???????????????ret =
> pm_genpd_remove(&imx_gpc_domains[GPC_PGC_DOMAIN_PU].base);
> -???????????????if (ret)
> -???????????????????????return ret;
> -???????????????imx_pgc_put_clocks(&imx_gpc_domains[GPC_PGC_DOMAIN_PU
> ]);
> -
> -???????????????ret =
> pm_genpd_remove(&imx_gpc_domains[GPC_PGC_DOMAIN_ARM].base);
> -???????????????if (ret)
> -???????????????????????return ret;
> -???????}
> -
> -???????return 0;
> -}
> -
> ?static struct platform_driver imx_gpc_driver = {
> ????????.driver = {
> ????????????????.name = "imx-gpc",
> ????????????????.of_match_table = imx_gpc_dt_ids,
> +????????????????/*
> +?????????????????* We can't forcibly eject devices form power
> domain,
> +?????????????????* so we can't really remove power domains once they
> +?????????????????* were added.
> +?????????????????*/
> +????????????????.suppress_bind_attrs = true,
> ????????},
> ????????.probe = imx_gpc_probe,
> -???????.remove = imx_gpc_remove,
> ?};
> ?builtin_platform_driver(imx_gpc_driver)
> 
> Regards
> Dong Aisheng
> 
> > +	struct device_node *pgc_node;
> > ?	int ret;
> > ?
> > +	pgc_node = of_get_child_by_name(pdev->dev.of_node, "pgc");
> > +
> > +	/* bail out if DT too old and doesn't provide the
> > necessary info */
> > +	if (!of_property_read_bool(pdev->dev.of_node, "#power-
> > domain-cells") &&
> > +	????!pgc_node)
> > +		return 0;
> > +
> > ?	/*
> > ?	?* If the old DT binding is used the toplevel driver needs
> > to
> > ?	?* de-register the power domains
> > ?	?*/
> > -	if (!of_get_child_by_name(pdev->dev.of_node, "pgc")) {
> > +	if (!pgc_node) {
> > ?		of_genpd_del_provider(pdev->dev.of_node);
> > ?
> > ?		ret =
> > pm_genpd_remove(&imx_gpc_domains[GPC_PGC_DOMAIN_PU].base);
> > --?
> > 2.15.1
> >