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From: Mark Brown <broonie@kernel.org>
To: Sowjanya Komatineni <skomatineni@nvidia.com>
Cc: thierry.reding@gmail.com, jonathanh@nvidia.com, talho@nvidia.com,
	robh+dt@kernel.org, mark.rutland@arm.com, kyarlagadda@nvidia.com,
	ldewangan@nvidia.com, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH V1 18/26] spi: tegra114: add support for hw based cs
Date: Mon, 1 Apr 2019 14:48:57 +0700	[thread overview]
Message-ID: <20190401074857.GK2059@sirena.org.uk> (raw)
In-Reply-To: <1553666207-11414-18-git-send-email-skomatineni@nvidia.com>

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On Tue, Mar 26, 2019 at 10:56:39PM -0700, Sowjanya Komatineni wrote:

> Tegra SPI driver default uses SW CS control for transfers and HW CS
> control can be enabled through SPI client device node DT property
> nvidia,enable-hw-based-cs and is used only for single transfers.

Why have a property - if this feature works and is useful why would a
system ever not want to use it?

> +	single_xfer = list_is_singular(&msg->transfers);
>  	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
>  		u32 cmd1;
>  
>  		reinit_completion(&tspi->xfer_completion);
>  
> -		cmd1 = tegra_spi_setup_transfer_one(spi, xfer, is_first_msg);
> +		cmd1 = tegra_spi_setup_transfer_one(spi, xfer, is_first_msg,
> +						    single_xfer);

It's not sufficient to check if there's only one transfer, you also need
to make sure that the driver isn't using cs_change to use non-standard
chip select handling.

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  reply	other threads:[~2019-04-01  7:49 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-27  5:56 [PATCH V1 01/26] spi: tegra114: fix PIO transfer Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 02/26] spi: tegra114: clear packed bit for unpacked mode Sowjanya Komatineni
2019-04-01  8:54   ` Applied "spi: tegra114: clear packed bit for unpacked mode" to the spi tree Mark Brown
2019-03-27  5:56 ` [PATCH V1 03/26] spi: tegra114: fix for unpacked mode transfers Sowjanya Komatineni
2019-04-01  8:54   ` Applied "spi: tegra114: fix for unpacked mode transfers" to the spi tree Mark Brown
2019-03-27  5:56 ` [PATCH V1 04/26] spi: tegra114: use packed mode for 32 bits per word Sowjanya Komatineni
2019-04-01  7:39   ` Mark Brown
2019-04-01 18:38     ` Sowjanya Komatineni
2019-04-01  8:54   ` Applied "spi: tegra114: use packed mode for 32 bits per word" to the spi tree Mark Brown
2019-03-27  5:56 ` [PATCH V1 05/26] spi: tegra114: use unpacked mode for below 4 byte transfers Sowjanya Komatineni
2019-04-01  8:26   ` Mark Brown
2019-03-27  5:56 ` [PATCH V1 06/26] spi: tegra114: terminate dma and reset on transfer timeout Sowjanya Komatineni
2019-04-01  8:54   ` Applied "spi: tegra114: terminate dma and reset on transfer timeout" to the spi tree Mark Brown
2019-03-27  5:56 ` [PATCH V1 07/26] spi: tegra114: flush fifos Sowjanya Komatineni
2019-04-01  8:54   ` Applied "spi: tegra114: flush fifos" to the spi tree Mark Brown
2019-03-27  5:56 ` [PATCH V1 08/26] spi: tegra114: configure dma burst size to fifo trig level Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 09/26] spi: tegra114: dump SPI registers during timeout Sowjanya Komatineni
2019-04-01  7:39   ` Mark Brown
2019-03-27  5:56 ` [PATCH V1 10/26] spi: tegra114: avoid reset call in atomic context Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 11/26] spi: tegra114: reset controller on probe Sowjanya Komatineni
2019-04-01  8:54   ` Applied "spi: tegra114: reset controller on probe" to the spi tree Mark Brown
2019-03-27  5:56 ` [PATCH V1 12/26] spi: tegra114: add SPI_LSB_FIRST support Sowjanya Komatineni
2019-04-01  8:54   ` Applied "spi: tegra114: add SPI_LSB_FIRST support" to the spi tree Mark Brown
2019-03-27  5:56 ` [PATCH V1 13/26] spi: tegra114: add dual mode support Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 14/26] spi: tegra114: add 3 wire transfer " Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 15/26] spi: tegra114: set supported bits_per_word Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 16/26] spi: tegra114: set bus number based on id Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 17/26] spi: tegra114: add support for interrupt mask Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 18/26] spi: tegra114: add support for hw based cs Sowjanya Komatineni
2019-04-01  7:48   ` Mark Brown [this message]
2019-04-01 18:40     ` Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 19/26] DT bindings: spi: add spi client device properties Sowjanya Komatineni
2019-04-01  7:37   ` Mark Brown
2019-04-01 17:59     ` Sowjanya Komatineni
2019-04-02  4:52       ` Mark Brown
2019-03-27  5:56 ` [PATCH V1 20/26] spi: tegra114: add support for tuning HW CS timing Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 21/26] DT bindings: spi: add tx/rx clock delay SPI client properties Sowjanya Komatineni
2019-03-31  6:42   ` Rob Herring
2019-04-02 20:27     ` Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 22/26] spi: tegra114: add support for tuning clock delay Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 23/26] spi: tegra114: add support for gpio based cs Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 24/26] spi: tegra114: de-assert CS before SPI mode is reset to its default Sowjanya Komatineni
2019-04-01  7:49   ` Mark Brown
2019-04-01 18:07     ` Sowjanya Komatineni
2019-04-02  4:52       ` Mark Brown
2019-03-27  5:56 ` [PATCH V1 25/26] spi: expand mode and mode_bits support Sowjanya Komatineni
2019-03-27  5:56 ` [PATCH V1 26/26] spi: tegra114: add support for LSBYTE_FIRST Sowjanya Komatineni

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