From: Pavel Machek <pavel@denx.de>
To: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Pavel Machek <pavel@denx.de>,
"cip-dev@lists.cip-project.org" <cip-dev@lists.cip-project.org>,
Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>,
Chris Paterson <Chris.Paterson2@renesas.com>,
Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Subject: Re: [PATCH 5.10.y-cip 5/7] serial: 8250_em: Use pseudo offset for UART_FCR
Date: Thu, 15 Jun 2023 10:27:38 +0200 [thread overview]
Message-ID: <ZIrLeqKXeOmi9R62@duo.ucw.cz> (raw)
In-Reply-To: <OS0PR01MB59225C000B638ED14D74E10F865AA@OS0PR01MB5922.jpnprd01.prod.outlook.com>
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Hi!
> Thanks for the feedback.
>
> > Subject: Re: [PATCH 5.10.y-cip 5/7] serial: 8250_em: Use pseudo offset for
> > UART_FCR
> >
> > Hi!
> >
> > > commit 59d6558fb5fd750777edfde028ea1f9e7eed8a46 upstream.
> > >
> > > UART_FCR shares the same offset with UART_IIR. We cannot use UART_FCR
> > > in serial8250_em_serial_in() as it overlaps with UART_IIR.
> >
> > I don't follow the argument. AFAICT you could simply define UART_FCR to
> > UART_IIR, same readl() is used to read both.
>
> See https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/serial_reg.h#L53
>
> UART_FCR=2 and UART_IIR=2
>
> On reality from IP point, it is @0xC and @0x08.
Aha, thanks for explanation. So on some hardware IIR and FCR share the
same register, but not on yours?
It would be better if serial core provided different defines for the
two registers, as current situation is quite confusing.
Best regards,
Pavel
--
DENX Software Engineering GmbH, Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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next prev parent reply other threads:[~2023-06-15 8:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-13 13:23 [PATCH 5.10.y-cip 0/7] RZ/V2M UART FIFO support Biju Das
2023-06-13 13:23 ` [PATCH 5.10.y-cip 1/7] serial: 8250_em: Simplify probe() Biju Das
2023-06-13 13:23 ` [PATCH 5.10.y-cip 2/7] serial: 8250_em: Drop unused header file Biju Das
2023-06-13 13:23 ` [PATCH 5.10.y-cip 3/7] serial: 8250_em: Add missing break statement Biju Das
2023-06-13 13:23 ` [PATCH 5.10.y-cip 4/7] serial: 8250_em: Use devm_clk_get_enabled() Biju Das
2023-06-13 13:23 ` [PATCH 5.10.y-cip 5/7] serial: 8250_em: Use pseudo offset for UART_FCR Biju Das
2023-06-14 10:14 ` Pavel Machek
2023-06-14 13:41 ` Biju Das
2023-06-15 8:27 ` Pavel Machek [this message]
2023-06-13 13:23 ` [PATCH 5.10.y-cip 6/7] serial: 8250_em: Add serial8250_em_{reg_update(),out_helper()} Biju Das
2023-06-14 10:18 ` Pavel Machek
2023-06-14 13:44 ` Biju Das
2023-06-13 13:23 ` [PATCH 5.10.y-cip 7/7] arm64: dts: renesas: rzv2mevk2: Add uart0 pins Biju Das
2023-06-14 0:39 ` [PATCH 5.10.y-cip 0/7] RZ/V2M UART FIFO support nobuhiro1.iwamatsu
2023-06-15 8:23 ` Pavel Machek
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