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Date:   Mon, 27 Mar 2023 10:02:13 +0200
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Subject: Re: [PATCH] mtd: rawnand: stm32_fmc2: do not support EDO mode
From:   Christophe Kerello <christophe.kerello@foss.st.com>
To:     Miquel Raynal <miquel.raynal@bootlin.com>
CC:     <richard@nod.at>, <vigneshr@ti.com>,
        <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>
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Hello Miquel,

On 3/24/23 17:34, Christophe Kerello wrote:
> Hello Miquel,
> 
> On 3/24/23 17:25, Miquel Raynal wrote:
>> Hi Christophe,
>>
>> christophe.kerello@foss.st.com wrote on Fri, 24 Mar 2023 17:09:18 +0100:
>>
>>> FMC2 controller does not support EDO mode (timings mode 4 and 5).
>>>
>>> Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
>>> Fixes: 2cd457f328c1 ("mtd: rawnand: stm32_fmc2: add STM32 FMC2 NAND 
>>> flash controller driver")
>>> ---
>>>   drivers/mtd/nand/raw/stm32_fmc2_nand.c | 3 +++
>>>   1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/mtd/nand/raw/stm32_fmc2_nand.c 
>>> b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
>>> index 5d627048c420..3abb63d00a0b 100644
>>> --- a/drivers/mtd/nand/raw/stm32_fmc2_nand.c
>>> +++ b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
>>> @@ -1531,6 +1531,9 @@ static int 
>>> stm32_fmc2_nfc_setup_interface(struct nand_chip *chip, int chipnr,
>>>       if (IS_ERR(sdrt))
>>>           return PTR_ERR(sdrt);
>>> +    if (sdrt->tRC_min < 30000)
>>
>> When introducing NV-DDR support we as well added a timings.mode field,
>> perhaps you could use it?
> 
> Yes, I can use it. It will be done in V2.
> 
> Regards,
> Christophe Kerello.
> 

I had a look at Kernel LTS, and timings.mode was introduced on Kernel 
LTS 5.10. As this patch has also to be applied on Kernel LTS 5.4, my 
proposal is to send a new patch set. The first patch will be the current 
patch (fix for all Kernel LTS) and the second patch will use 
timings.mode instead of checking tRC_min timings for next Kernel 
delivery. Is this proposal acceptable?

Regards,
Christophe Kerello.

>>
>>> +        return -EOPNOTSUPP;
>>> +
>>>       if (chipnr == NAND_DATA_IFACE_CHECK_ONLY)
>>>           return 0;
>>
>>
>> Thanks,
>> Miquèl