Re: [PATCH 1/2] net: allwinner: reset control support

[Evgeny Boger]

Hi, thank you for your review!


3/8/21 4:36 PM, Maxime Ripard пишет:
> Hi,
>
> On Sun, Mar 07, 2021 at 06:13:51AM +0300, Evgeny Boger wrote:
> > R40 (aka V40/A40i/T3) and A10/A20 share the same EMAC IP.
> > However, on R40 the EMAC is gated by default.
> >
> > Signed-off-by: Evgeny Boger <boger@xxxxxxxxxxxxxx>
> On which device was it tested?
It's custom-made Allwinner A40i device with two IP101GRI PHYs in MII mode.
> > ---
> >   drivers/net/ethernet/allwinner/sun4i-emac.c | 21 ++++++++++++++++++++-
> >   1 file changed, 20 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c b/drivers/net/ethernet/allwinner/sun4i-emac.c
> > index 5ed80d9a6b9f..c0ae06dd922c 100644
> > --- a/drivers/net/ethernet/allwinner/sun4i-emac.c
> > +++ b/drivers/net/ethernet/allwinner/sun4i-emac.c
> > @@ -28,6 +28,7 @@
> >   #include <linux/of_platform.h>
> >   #include <linux/platform_device.h>
> >   #include <linux/phy.h>
> > +#include <linux/reset.h>
> >   #include <linux/soc/sunxi/sunxi_sram.h>
> >   
> >   #include "sun4i-emac.h"
> > @@ -85,6 +86,7 @@ struct emac_board_info {
> >   	unsigned int		link;
> >   	unsigned int		speed;
> >   	unsigned int		duplex;
> > +	struct reset_control *reset;
> You should align this with the rest of the other fields

> >   
> >   	phy_interface_t		phy_interface;
> >   };
> > @@ -791,6 +793,7 @@ static int emac_probe(struct platform_device *pdev)
> >   	struct net_device *ndev;
> >   	int ret = 0;
> >   	const char *mac_addr;
> > +	struct reset_control *reset;
> >   
> >   	ndev = alloc_etherdev(sizeof(struct emac_board_info));
> >   	if (!ndev) {
> > @@ -852,6 +855,19 @@ static int emac_probe(struct platform_device *pdev)
> >   		goto out_release_sram;
> >   	}
> >   
> > +	reset = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
> > +	if (IS_ERR(reset)) {
> > +		dev_err(&pdev->dev, "unable to request reset\n");
> > +		ret = -ENODEV;
> > +		goto out_release_sram;
> > +	}
> Judging from your commit log, it's not really optional for the R40. The
> way we usually deal with this is to have a structure associated with a
> new compatible and have a flag tell if that compatible requires a reset
> line or not.
>
> The dt binding should also be amended to allow the reset property
got it
> > +	db->reset = reset;
> > +	ret = reset_control_deassert(db->reset);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "could not deassert EMAC reset\n");
> > +		goto out_release_sram;
> > +	}
> > +
> The programming guidelines in the datasheet ask that the reset line must
> be deasserted before the clock in enabled.
right, found it at section 3.3.2.6, thanks
> Maxime