Re: [PATCH v4 8/9] i2c: piix4: Add EFCH MMIO support for SMBus port select

From: Jean Delvare <jdelvare@suse.de>
To: Terry Bowman <terry.bowman@amd.com>
Cc: <linux@roeck-us.net>, <linux-watchdog@vger.kernel.org>,
	<linux-i2c@vger.kernel.org>, <wsa@kernel.org>,
	<andy.shevchenko@gmail.com>, <rafael.j.wysocki@intel.com>,
	<linux-kernel@vger.kernel.org>, <wim@linux-watchdog.org>,
	<rrichter@amd.com>, <thomas.lendacky@amd.com>,
	<sudheesh.mavila@amd.com>, <Nehal-bakulchandra.Shah@amd.com>,
	<Basavaraj.Natikar@amd.com>, <Shyam-sundar.S-k@amd.com>,
	<Mario.Limonciello@amd.com>
Subject: Re: [PATCH v4 8/9] i2c: piix4: Add EFCH MMIO support for SMBus port select
Date: Tue, 8 Feb 2022 17:19:41 +0100	[thread overview]
Message-ID: <20220208171941.18156714@endymion.delvare> (raw)
In-Reply-To: <20220130184130.176646-9-terry.bowman@amd.com>

Hi Terry,

On Sun, 30 Jan 2022 12:41:29 -0600, Terry Bowman wrote:
> AMD processors include registers capable of selecting between 2 SMBus
> ports. Port selection is made during each user access by writing to
> FCH::PM::DECODEEN[smbus0sel]. Change the driver to use MMIO during
> SMBus port selection because cd6h/cd7h port I/O is not available on
> later AMD processors.
> 
> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
> ---
>  drivers/i2c/busses/i2c-piix4.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> (...)
> @@ -765,6 +774,7 @@ static int piix4_sb800_port_sel(u8 port)
>  
>  	return (smba_en_lo & piix4_port_mask_sb800);
>  }
> +
>  /*
>   * Handles access to multiple SMBus ports on the SB800.
>   * The port is selected by bits 2:1 of the smb_en register (0x2c).

We indeed want a blank line here, but it should be inserted in patch
[5/9] (which adds function piix4_sb800_port_sel), not in this patch.

-- 
Jean Delvare
SUSE L3 Support