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From: Krishna Yarlagadda <kyarlagadda@nvidia.com>
To: <robh+dt@kernel.org>, <broonie@kernel.org>, <peterhuewe@gmx.de>,
	<jgg@ziepe.ca>, <jarkko@kernel.org>,
	<krzysztof.kozlowski+dt@linaro.org>, <linux-spi@vger.kernel.org>,
	<linux-tegra@vger.kernel.org>, <linux-integrity@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Cc: <thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
	<skomatineni@nvidia.com>, <ldewangan@nvidia.com>,
	Krishna Yarlagadda <kyarlagadda@nvidia.com>
Subject: [Patch V6 1/3] spi: Add TPM HW flow flag
Date: Mon, 27 Feb 2023 22:51:06 +0530	[thread overview]
Message-ID: <20230227172108.8206-2-kyarlagadda@nvidia.com> (raw)
In-Reply-To: <20230227172108.8206-1-kyarlagadda@nvidia.com>

TPM spec defines flow control over SPI. Client device can insert a wait
state on MISO when address is trasmitted by controller on MOSI. It can
work only on full duplex.
Half duplex controllers need to implement flow control in HW.
Add a flag for TPM to indicate flow control is expected in controller.

Signed-off-by: Krishna Yarlagadda <kyarlagadda@nvidia.com>
---
 include/linux/spi/spi.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 4fa26b9a3572..6b32c90e9e20 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -184,8 +184,9 @@ struct spi_device {
 	u8			chip_select;
 	u8			bits_per_word;
 	bool			rt;
-#define SPI_NO_TX	BIT(31)		/* No transmit wire */
-#define SPI_NO_RX	BIT(30)		/* No receive wire */
+#define SPI_NO_TX		BIT(31)		/* No transmit wire */
+#define SPI_NO_RX		BIT(30)		/* No receive wire */
+#define SPI_TPM_HW_FLOW		BIT(29)		/* TPM flow control */
 	/*
 	 * All bits defined above should be covered by SPI_MODE_KERNEL_MASK.
 	 * The SPI_MODE_KERNEL_MASK has the SPI_MODE_USER_MASK counterpart,
@@ -195,7 +196,7 @@ struct spi_device {
 	 * These bits must not overlap. A static assert check should make sure of that.
 	 * If adding extra bits, make sure to decrease the bit index below as well.
 	 */
-#define SPI_MODE_KERNEL_MASK	(~(BIT(30) - 1))
+#define SPI_MODE_KERNEL_MASK	(~(BIT(29) - 1))
 	u32			mode;
 	int			irq;
 	void			*controller_state;
-- 
2.17.1


  reply	other threads:[~2023-02-27 17:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-27 17:21 [Patch V6 0/3] Tegra TPM driver with HW flow control Krishna Yarlagadda
2023-02-27 17:21 ` Krishna Yarlagadda [this message]
2023-03-01 13:34   ` [Patch V6 1/3] spi: Add TPM HW flow flag Thierry Reding
2023-03-01 15:27     ` Krishna Yarlagadda
2023-02-27 17:21 ` [Patch V6 2/3] tpm_tis-spi: Support hardware wait polling Krishna Yarlagadda
2023-03-01 13:37   ` Thierry Reding
2023-02-27 17:21 ` [Patch V6 3/3] spi: tegra210-quad: Enable TPM " Krishna Yarlagadda
2023-03-01 13:39   ` Thierry Reding
2023-03-01 13:41   ` Thierry Reding
2023-03-01 13:51   ` Jon Hunter

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