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From: Ji Sheng Teoh <jisheng.teoh@starfivetech.com>
To: Mark Brown <broonie@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Michal Simek <michal.simek@amd.com>
Cc: Ji Sheng Teoh <jisheng.teoh@starfivetech.com>,
	Ley Foon Tan <leyfoon.tan@starfivetech.com>,
	linux-spi@vger.kernel.org,
	devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Eng Lee Teh <englee.teh@starfivetech.com>
Subject: [PATCH v1 1/2] spi: spi-cadence: Add optional reset control support
Date: Wed, 24 Apr 2024 13:13:16 +0800
Message-ID: <20240424051317.2084059-2-jisheng.teoh@starfivetech.com>
In-Reply-To: <20240424051317.2084059-1-jisheng.teoh@starfivetech.com>
References: <20240424051317.2084059-1-jisheng.teoh@starfivetech.com>
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Add optional reset control support for spi-cadence to properly bring
the SPI device into an operating condition.

Signed-off-by: Eng Lee Teh <englee.teh@starfivetech.com>
Signed-off-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Signed-off-by: Ji Sheng Teoh <jisheng.teoh@starfivetech.com>
---
 drivers/spi/spi-cadence.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index e5140532071d..41f2f51d39e4 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -111,6 +111,7 @@
  * @dev_busy:		Device busy flag
  * @is_decoded_cs:	Flag for decoder property set or not
  * @tx_fifo_depth:	Depth of the TX FIFO
+ * @rstc:		Optional reset control for SPI controller
  */
 struct cdns_spi {
 	void __iomem *regs;
@@ -125,6 +126,7 @@ struct cdns_spi {
 	u8 dev_busy;
 	u32 is_decoded_cs;
 	unsigned int tx_fifo_depth;
+	struct reset_control *rstc;
 };
 
 /* Macros for the SPI controller read/write */
@@ -588,6 +590,16 @@ static int cdns_spi_probe(struct platform_device *pdev)
 		goto remove_ctlr;
 	}
 
+	xspi->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(xspi->rstc)) {
+		ret = PTR_ERR(xspi->rstc);
+		dev_err(&pdev->dev, "Cannot get SPI reset.\n");
+		goto remove_ctlr;
+	}
+
+	reset_control_assert(xspi->rstc);
+	reset_control_deassert(xspi->rstc);
+
 	if (!spi_controller_is_target(ctlr)) {
 		xspi->ref_clk = devm_clk_get_enabled(&pdev->dev, "ref_clk");
 		if (IS_ERR(xspi->ref_clk)) {
-- 
2.43.2