[U-Boot] [PATCH 04/11] net: macb: Fix clk API usage for RISC-V systems

[Anup Patel]

> -----Original Message-----
> From: Alexander Graf [mailto:agraf at suse.de]
> Sent: Thursday, January 17, 2019 11:37 PM
> To: Anup Patel <Anup.Patel at wdc.com>; Rick Chen <rick at andestech.com>;
> Bin Meng <bmeng.cn at gmail.com>; Joe Hershberger
> <joe.hershberger at ni.com>; Lukas Auer <lukas.auer at aisec.fraunhofer.de>;
> Masahiro Yamada <yamada.masahiro at socionext.com>; Simon Glass
> <sjg at chromium.org>
> Cc: Palmer Dabbelt <palmer at sifive.com>; Paul Walmsley
> <paul.walmsley at sifive.com>; Atish Patra <Atish.Patra at wdc.com>;
> Christoph Hellwig <hch at infradead.org>; U-Boot Mailing List <u-
> boot at lists.denx.de>
> Subject: Re: [PATCH 04/11] net: macb: Fix clk API usage for RISC-V systems
> 
> On 01/17/2019 11:38 AM, Anup Patel wrote:
> > This patch does following fixes in MACB ethernet driver for using it
> > on RISC-V systems (particularly QEMU sifive_u
> > machine):
> > 1. asm/arch/clk.h is not available on RISC-V port so include
> >     it only for non-RISC-V systems.
> > 2. Don't fail in macb_enable_clk() if clk_enable() returns
> >     -ENOSYS because we get -ENOSYS for fixed-rate clocks.
> >
> > Signed-off-by: Anup Patel <anup.patel at wdc.com>
> > Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
> > ---
> >   drivers/net/macb.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/macb.c b/drivers/net/macb.c index
> > 94c89c762b..9a06b523cc 100644
> > --- a/drivers/net/macb.c
> > +++ b/drivers/net/macb.c
> > @@ -38,7 +38,9 @@
> >   #include <linux/mii.h>
> >   #include <asm/io.h>
> >   #include <asm/dma-mapping.h>
> > +#ifndef CONFIG_RISCV
> >   #include <asm/arch/clk.h>
> > +#endif
> >   #include <linux/errno.h>
> >
> >   #include "macb.h"
> > @@ -1066,7 +1068,7 @@ static int macb_enable_clk(struct udevice *dev)
> >   	 */
> >   #ifndef CONFIG_MACB_ZYNQ
> >   	ret = clk_enable(&clk);
> 
> If clk.h is not available, who exports clk_enable() then; and why is the
> included needed in the first place?

For some of the ARM boards, clk instances are provided
directly by arch/arm/mach-xyz sources. For such boards,
asm/arch/clk.h is required. I think these boards should
move to DT based clk drivers.

In all other cases, we use generic <clk.h> which provides
clk instances using DT based clk drivers.

Regards,
Anup