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Message-ID: <7d2aacbe-9725-2c15-38b7-deb56184f82b@arinc9.com>
Date: Thu, 25 May 2023 10:04:23 +0300
From: Arınç ÜNAL <arinc.unal@...nc9.com>
To: Vladimir Oltean <olteanv@...il.com>
Cc: Sean Wang <sean.wang@...iatek.com>, Landen Chao
<Landen.Chao@...iatek.com>, DENG Qingfang <dqfext@...il.com>,
Daniel Golle <daniel@...rotopia.org>, Andrew Lunn <andrew@...n.ch>,
Florian Fainelli <f.fainelli@...il.com>,
"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
Matthias Brugger <matthias.bgg@...il.com>,
AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
Russell King <linux@...linux.org.uk>,
Richard van Schagen <richard@...terhints.com>,
Richard van Schagen <vschagen@...com>,
Frank Wunderlich <frank-w@...lic-files.de>,
Bartel Eerdekens <bartel.eerdekens@...stell8.be>, erkin.bozoglu@...ont.com,
mithat.guner@...ont.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH net-next 12/30] net: dsa: mt7530: move XTAL check to
mt7530_setup()
On 24.05.2023 21:15, Vladimir Oltean wrote:
> On Mon, May 22, 2023 at 03:15:14PM +0300, arinc9.unal@...il.com wrote:
>> From: Arınç ÜNAL <arinc.unal@...nc9.com>
>>
>> The crystal frequency concerns the switch core. The frequency should be
>> checked when the switch is being set up so the driver can reject the
>> unsupported hardware earlier and without requiring port 6 to be used.
>>
>> Move it to mt7530_setup().
>>
>> Tested-by: Arınç ÜNAL <arinc.unal@...nc9.com>
>> Signed-off-by: Arınç ÜNAL <arinc.unal@...nc9.com>
>> ---
>
> Do you know why a crystal frequency of 20 MHz is not supported?
I don't know, it just isn't.
https://github.com/BPI-SINOVOIP/BPI-R2-bsp/blob/master/linux-mt/drivers/net/ethernet/mediatek/gsw_mt7623.c#L1076
>
>> drivers/net/dsa/mt7530.c | 18 ++++++++++--------
>> 1 file changed, 10 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
>> index 049f7be0d790..fa48273269c4 100644
>> --- a/drivers/net/dsa/mt7530.c
>> +++ b/drivers/net/dsa/mt7530.c
>> @@ -408,13 +408,6 @@ mt7530_setup_port6(struct dsa_switch *ds, phy_interface_t interface)
>>
>> xtal = mt7530_read(priv, MT7530_HWTRAP) & HWTRAP_XTAL_MASK;
>>
>> - if (xtal == HWTRAP_XTAL_20MHZ) {
>> - dev_err(priv->dev,
>> - "%s: MT7530 with a 20MHz XTAL is not supported!\n",
>> - __func__);
>> - return -EINVAL;
>> - }
>> -
>> switch (interface) {
>> case PHY_INTERFACE_MODE_RGMII:
>> trgint = 0;
>> @@ -2133,7 +2126,7 @@ mt7530_setup(struct dsa_switch *ds)
>> struct mt7530_dummy_poll p;
>> phy_interface_t interface;
>> struct dsa_port *cpu_dp;
>> - u32 id, val;
>> + u32 id, val, xtal;
>> int ret, i;
>>
>> /* The parent node of master netdev which holds the common system
>> @@ -2203,6 +2196,15 @@ mt7530_setup(struct dsa_switch *ds)
>> return -ENODEV;
>> }
>>
>> + xtal = mt7530_read(priv, MT7530_HWTRAP) & HWTRAP_XTAL_MASK;
>> +
>> + if (xtal == HWTRAP_XTAL_20MHZ) {
>> + dev_err(priv->dev,
>> + "%s: MT7530 with a 20MHz XTAL is not supported!\n",
>> + __func__);
>
> I don't think __func__ brings much value here, it could be dropped in
> the process of moving the code.
Will do.
>
> Also, the HWTRAP register is already read once, here (stored in "val"):
>
> INIT_MT7530_DUMMY_POLL(&p, priv, MT7530_HWTRAP);
> ret = readx_poll_timeout(_mt7530_read, &p, val, val != 0,
> 20, 1000000);
>
> I wonder if we really need to read it twice.
Likely not, good catch.
Arınç
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