linux-kernel - Re: [PATCH v2 3/3] spi: spi-microchip-core: Add support for GPIO based CS

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Message-ID: <20240514-malt-diffuser-2fd207015e72@spud>
Date: Tue, 14 May 2024 18:57:04 +0100
From: Conor Dooley <conor@...nel.org>
To: Prajna Rajendra Kumar <prajna.rajendrakumar@...rochip.com>
Cc: Mark Brown <broonie@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	linux-riscv@...ts.infradead.org, linux-spi@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	Conor Dooley <conor.dooley@...rochip.com>,
	Daire McNamara <daire.mcnamara@...rochip.com>,
	valentina.fernandezalanis@...rochip.com
Subject: Re: [PATCH v2 3/3] spi: spi-microchip-core: Add support for GPIO
 based CS

Prajna, Mark,

On Tue, May 14, 2024 at 11:45:08AM +0100, Prajna Rajendra Kumar wrote:
> The SPI "hard" controller within the PolarFire SoC is capable of
> handling eight CS lines, but only one CS line is wired. Therefore, use
> GPIO descriptors to configure additional CS lines.
> 
> Signed-off-by: Prajna Rajendra Kumar <prajna.rajendrakumar@...rochip.com>

I provided an ack on v1, so here it is again:
Acked-by: Conor Dooley <conor.dooley@...rochip.com>

In general you can keep tags between versions, if you intentionally drop
tags you should mention why you dropped them.

> ---
>  drivers/spi/spi-microchip-core.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/spi/spi-microchip-core.c b/drivers/spi/spi-microchip-core.c
> index c10de45aa472..6246254e1dff 100644
> --- a/drivers/spi/spi-microchip-core.c
> +++ b/drivers/spi/spi-microchip-core.c
> @@ -258,6 +258,9 @@ static int mchp_corespi_setup(struct spi_device *spi)
>  	struct mchp_corespi *corespi = spi_controller_get_devdata(spi->controller);
>  	u32 reg;
>  
> +	if (spi_is_csgpiod(spi))
> +		return 0;

Mark,

This has no users outside of core code, but is < 6 months old. Is using
it in a driver like this okay?

Cheers,
Conor.

> +
>  	/*
>  	 * Active high targets need to be specifically set to their inactive
>  	 * states during probe by adding them to the "control group" & thus
> @@ -516,6 +519,7 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>  
>  	host->num_chipselect = num_cs;
>  	host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
> +	host->use_gpio_descriptors = true;
>  	host->setup = mchp_corespi_setup;
>  	host->bits_per_word_mask = SPI_BPW_MASK(8);
>  	host->transfer_one = mchp_corespi_transfer_one;
> -- 
> 2.25.1
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

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