Messages in this thread | | | Date | Thu, 12 Apr 2018 23:11:08 +0800 | Subject | Re: [PATCH 3/5] net: stmmac: dwmac-sun8i: Allow getting syscon regmap from device | From | Icenowy Zheng <> |
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于 2018年4月12日 GMT+08:00 下午10:56:28, Maxime Ripard <maxime.ripard@bootlin.com> 写到: >On Wed, Apr 11, 2018 at 10:16:39PM +0800, Icenowy Zheng wrote: >> From: Chen-Yu Tsai <wens@csie.org> >> >> On the Allwinner R40 SoC, the "GMAC clock" register is in the CCU >> address space; on the A64 SoC this register is in the SRAM controller >> address space, and with a different offset. >> >> To access the register from another device and hide the internal >> difference between the device, let it register a regmap named >> "emac-clock". We can then get the device from the phandle, and >> retrieve the regmap with dev_get_regmap(); in this situation the >> regmap_field will be set up to access the only register in the >regmap. >> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org> >> [Icenowy: change to use regmaps with single register, change commit >> message] >> Signed-off-by: Icenowy Zheng <icenowy@aosc.io> >> --- >> drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 48 >++++++++++++++++++++++- >> 1 file changed, 46 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c >b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c >> index 1037f6c78bca..b61210c0d415 100644 >> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c >> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c >> @@ -85,6 +85,13 @@ const struct reg_field old_syscon_reg_field = { >> .msb = 31, >> }; >> >> +/* Specially exported regmap which contains only EMAC register */ >> +const struct reg_field single_reg_field = { >> + .reg = 0, >> + .lsb = 0, >> + .msb = 31, >> +}; >> + > >I'm not sure this would be wise. If we ever need some other register >exported through the regmap, will have to change all the calling sites >everywhere in the kernel, which will be a pain and will break >bisectability.
In this situation the register can be exported as another regmap. Currently the code will access a regmap with name "emac-clock" for this register.
> >Chen-Yu's (or was it yours?) initial solution with a custom writeable >hook only allowing a single register seemed like a better one.
But I remember you mentioned that you want it to hide the difference inside the device.
> >Maxime
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