Re: [PATCH v4 18/23] ata: libahci_platform: Add function returning a clock-handle by id

Serge Semin
2022-06-15T21:24:54Z

On Tue, Jun 14, 2022 at 05:45:35PM +0900, Damien Le Moal wrote:
> On 6/10/22 17:17, Serge Semin wrote:
> > Since all the clocks are retrieved by the method
> > ahci_platform_get_resources() there is no need for the LLD (glue) drivers
> > to be looking for some particular of them in the kernel clocks table
> > again. Instead we suggest to add a simple method returning a
> > device-specific clock with passed connection ID if it is managed to be
> > found. Otherwise the function will return NULL. Thus the glue-drivers
> > won't need to either manually touching the hpriv->clks array or calling
> > clk_get()-friends. The AHCI platform drivers will be able to use the new
> > function right after the ahci_platform_get_resources() method invocation
> > and up to the device removal.
> >
> > Note the method is left unused here, but will be utilized in the framework
> > of the DWC AHCI SATA driver being added in the next commit.
> >
> > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> >
> > ---
> >
> > Changelog v2:
> > - Fix some grammar mistakes in the method description.
> >
> > Changelog v4:
> > - Add a note regarding the new method usage.
> > ---
> > drivers/ata/libahci_platform.c | 27 +++++++++++++++++++++++++++
> > include/linux/ahci_platform.h | 3 +++
> > 2 files changed, 30 insertions(+)
> >
> > diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
> > index 8b542a8bc487..418961f954af 100644
> > --- a/drivers/ata/libahci_platform.c
> > +++ b/drivers/ata/libahci_platform.c
> > @@ -95,6 +95,33 @@ void ahci_platform_disable_phys(struct ahci_host_priv *hpriv)
> > }
> > EXPORT_SYMBOL_GPL(ahci_platform_disable_phys);
> >
> > +/**
> > + * ahci_platform_find_clk - Find platform clock
> > + * @hpriv: host private area to store config values
> > + * @con_id: clock connection ID
> > + *
> > + * This function returns a pointer to the clock descriptor of the clock with
> > + * the passed ID.
> > + *
> > + * RETURNS:
> > + * Pointer to the clock descriptor on success otherwise NULL
> > + */
> > +struct clk *ahci_platform_find_clk(struct ahci_host_priv *hpriv, const char *con_id)
> > +{
> > + struct clk *clk = NULL;
> > + int i;
> > +
> > + for (i = 0; i < hpriv->n_clks; i++) {
> > + if (!strcmp(hpriv->clks[i].id, con_id)) {
> > + clk = hpriv->clks[i].clk;
>
> return hpriv->clks[i].clk;
>
> > + break;
> > + }
> > + }
> > +
> > + return clk;
>

> And then "return NULL;" here and you do not need the clk variable.

Ok.

>
> > +}
> > +EXPORT_SYMBOL_GPL(ahci_platform_find_clk);
> > +
> > /**
> > * ahci_platform_enable_clks - Enable platform clocks
> > * @hpriv: host private area to store config values
> > diff --git a/include/linux/ahci_platform.h b/include/linux/ahci_platform.h
> > index 6d7dd472d370..3418980b0341 100644
> > --- a/include/linux/ahci_platform.h
> > +++ b/include/linux/ahci_platform.h
> > @@ -13,6 +13,7 @@
> >
> > #include <linux/compiler.h>
> >
> > +struct clk;
> > struct device;
> > struct ata_port_info;
> > struct ahci_host_priv;
> > @@ -21,6 +22,8 @@ struct scsi_host_template;
> >
> > int ahci_platform_enable_phys(struct ahci_host_priv *hpriv);
> > void ahci_platform_disable_phys(struct ahci_host_priv *hpriv);
> > +struct clk *
> > +ahci_platform_find_clk(struct ahci_host_priv *hpriv, const char *con_id);
>

> Please make this:
>
> struct clk *ahci_platform_find_clk(struct ahci_host_priv *hpriv,
>
> const char *con_id);

Ok.

-Sergey

>
> > int ahci_platform_enable_clks(struct ahci_host_priv *hpriv);
> > void ahci_platform_disable_clks(struct ahci_host_priv *hpriv);
> > int ahci_platform_deassert_rsts(struct ahci_host_priv *hpriv);
>
>
> --
> Damien Le Moal
> Western Digital Research