Re: [PATCH v13 2/4] mtd: spi-nor: spansion: Add support for volatile QE bit

[Takahiro Kuwano <tkuw584924@gmail.com>]

On 4/21/2022 8:48 PM, Tudor.Ambarus@microchip.com wrote:
> On 4/21/22 14:36, Tudor.Ambarus@microchip.com wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> On 4/21/22 13:56, Tudor.Ambarus@microchip.com wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> On 4/21/22 13:47, Takahiro Kuwano wrote:
>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>>
>>>> On 4/21/2022 7:41 PM, Tudor.Ambarus@microchip.com wrote:
>>>>> On 4/21/22 12:40, tkuw584924@gmail.com wrote:
>>>> [...]
>>>>>> +/**
>>>>>> + * cypress_nor_quad_enable_volatile() - enable Quad I/O mode in volatile
>>>>>> + *                                      register.
>>>>>> + * @nor:       pointer to a 'struct spi_nor'
>>>>>> + *
>>>>>> + * It is recommended to update volatile registers in the field application due
>>>>>> + * to a risk of the non-volatile registers corruption by power interrupt. This
>>>>>> + * function sets Quad Enable bit in CFR1 volatile. If users set the Quad Enable
>>>>>> + * bit in the CFR1 non-volatile in advance (typically by a Flash programmer
>>>>>> + * before mounting Flash on PCB), the Quad Enable bit in the CFR1 volatile is
>>>>>> + * also set during Flash power-up.
>>>>>> + *
>>>>>> + * Return: 0 on success, -errno otherwise.
>>>>>> + */
>>>>>> +static int cypress_nor_quad_enable_volatile(struct spi_nor *nor)
>>>>>> +{
>>>>>> +       struct spi_mem_op op;
>>>>>> +       u8 cfr1v_written;
>>>>>> +       int ret;
>>>>>> +
>>>>>> +       op = (struct spi_mem_op)
>>>>>> +               CYPRESS_NOR_RD_ANY_REG_OP(3, SPINOR_REG_CYPRESS_CFR1V,
>>>>> nor->addr_width is 3, isn't it? can we use nor->addr_width instead of 3, please?
>>>>>
>>>> No, at the time this method is called, nor->addr_width is set to 4 by
>>>> spi_nor_set_addr_width().
>>>
>>> I see. Allow me some time to re-read this.
>>
>> Does this help you?
>> https://github.com/ambarus/linux-0day/commit/05f20ab7ee349628f0e2d22a4d3852038a6c8c70
> 
Yes, I have confirmed it's working on my hardware setup. Thanks a lot.

Some typos in commit description.
> commit 05f20ab7ee349628f0e2d22a4d3852038a6c8c70
> Author: Tudor Ambarus <tudor.ambarus@microchip.com>
> Date:   Thu Apr 21 14:15:42 2022 +0300
> 
>     mtd: spi-nor: core: Couple the number of address bytes with the address mode
>     
>     Some of Infineon chips support volatile version of configuration registers
>     and it is recommended to update volatile registers in the field application
>     due to a risk of the non-volatile registers corruption by power interrupt.
>     Such a volatile configuration register is used to enable the Quad mode.
>     The register write sequence requires the number of bytes of address in
>     order to be programmed. As it was before, the nor->addr_width was set to 4
>     before calling the volatile Quad enable method. This was incorrect as the
>     address mode was still at default (3-byte address), which resulted in
>     incorrect register configuration.
>     Move the setting of the number of bytes of adress after the the Quad enable
s/adress/address

>     method to allow reads or writes to registers that reguire the number of
s/reguire/require

>     address bytes to work with the default address mode. Now the number of
>     address bytes and the adress mode are tightly coupled, which is a natural
s/adress/address

Thanks again,
Takahiro

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