Re: [PATCH] Module argument to control whether intel-spi-pci attempts to turn the SPI flash chip writeable - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Daniel Gutson <daniel.gutson@eclypsium.com>
Cc: Richard Hughes <hughsient@gmail.com>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Boris Brezillon <bbrezillon@kernel.org>,
	Richard Weinberger <richard@nod.at>,
	Tudor Ambarus <tudor.ambarus@microchip.com>,
	linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Alex Bazhaniuk <alex@eclypsium.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>
Subject: Re: [PATCH] Module argument to control whether intel-spi-pci attempts to turn the SPI flash chip writeable
Date: Sat, 25 Jul 2020 07:56:49 +0200	[thread overview]
Message-ID: <20200725055649.GA1047853@kroah.com> (raw)
In-Reply-To: <20200724212853.11601-1-daniel.gutson@eclypsium.com>

On Fri, Jul 24, 2020 at 06:28:53PM -0300, Daniel Gutson wrote:
> Currently, intel-spi has a module argument that controls whether the driver
> attempts to turn the SPI flash chip writeable. The default value
> is FALSE (don't try to make it writeable).
> However, this flag applies only for a number of devices, coming from the
> platform driver, whereas the devices detected through the PCI driver
> (intel-spi-pci) are not subject to this check since the configuration
> takes place in intel-spi-pci which doesn't have an argument.
> 
> That's why I propose this patch to add such argument to intel-spi-pci,
> so the user can control whether the driver tries to make the chip
> writeable or not, being the default FALSE as is the argument of
> intel-spi.
> 
> Signed-off-by: Daniel Gutson <daniel.gutson@eclypsium.com>
> ---
>  drivers/mtd/spi-nor/controllers/intel-spi-pci.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/controllers/intel-spi-pci.c b/drivers/mtd/spi-nor/controllers/intel-spi-pci.c
> index 81329f680bec..77e57450f166 100644
> --- a/drivers/mtd/spi-nor/controllers/intel-spi-pci.c
> +++ b/drivers/mtd/spi-nor/controllers/intel-spi-pci.c
> @@ -24,6 +24,10 @@ static const struct intel_spi_boardinfo cnl_info = {
>  	.type = INTEL_SPI_CNL,
>  };
>  
> +static bool writeable;
> +module_param(writeable, bool, 0);
> +MODULE_PARM_DESC(writeable, "Enable write access to SPI flash chip (default=0)");

Ick, this isn't the 1990's, please do not add new module parameters,
they are a major pain to work with and only work on a global basis, not
on a per-device basis.

No user will remember how to use this, as it isn't documented anywhere
either.  Can you make this a sysfs attribute or something, or better
yet, make it "just work" depending on the device type?

thanks,

greg k-h

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