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From:   Sudip Mukherjee <sudip.mukherjee@sifive.com>
To:     Serge Semin <fancer.lancer@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc:     jude.onyenegecha@sifive.com, ben.dooks@sifive.com,
        jeegar.lakhani@sifive.com, linux-spi@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Sudip Mukherjee <sudip.mukherjee@sifive.com>
Subject: [PATCH v2 03/15] spi: dw: update SPI_CTRLR0 register
Date:   Mon, 12 Dec 2022 18:07:20 +0000
Message-Id: <20221212180732.79167-4-sudip.mukherjee@sifive.com>
In-Reply-To: <20221212180732.79167-1-sudip.mukherjee@sifive.com>
References: <20221212180732.79167-1-sudip.mukherjee@sifive.com>
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If the SPI transfer is being done in enhanced mode then SPI_CTRLR0
register needs to be updated to mention the instruction length, address
length, address and instruction transfer format, wait cycles. And, we
also need to enable clock stretching.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
---
 drivers/spi/spi-dw-core.c | 14 +++++++++++++-
 drivers/spi/spi-dw.h      | 11 +++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 8c47a4d14b666..d59401f16c47a 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -320,7 +320,7 @@ void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
 {
 	struct dw_spi_chip_data *chip = spi_get_ctldata(spi);
 	u32 cr0 = chip->cr0;
-	u32 speed_hz;
+	u32 speed_hz, spi_ctrlr0;
 	u16 clk_div;
 
 	/* CTRLR0[ 4/3: 0] or CTRLR0[ 20: 16] Data Frame Size */
@@ -365,6 +365,18 @@ void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
 		dw_writel(dws, DW_SPI_RX_SAMPLE_DLY, chip->rx_sample_dly);
 		dws->cur_rx_sample_dly = chip->rx_sample_dly;
 	}
+
+	if (cfg->spi_frf != DW_SPI_CTRLR0_SPI_FRF_STD_SPI) {
+		spi_ctrlr0 = DW_SPI_SPI_CTRLR0_CLK_STRETCH_EN;
+		spi_ctrlr0 |= FIELD_PREP(DW_SPI_SPI_CTRLR0_WAIT_CYCLE_MASK,
+					 cfg->wait_c);
+		spi_ctrlr0 |= FIELD_PREP(DW_SPI_SPI_CTRLR0_INST_L_MASK,
+					 cfg->inst_l);
+		spi_ctrlr0 |= FIELD_PREP(DW_SPI_SPI_CTRLR0_ADDR_L_MASK,
+					 cfg->addr_l);
+		spi_ctrlr0 |= cfg->trans_t;
+		dw_writel(dws, DW_SPI_SPI_CTRLR0, spi_ctrlr0);
+	}
 }
 EXPORT_SYMBOL_NS_GPL(dw_spi_update_config, SPI_DW_CORE);
 
diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
index 414a415deb42a..f29d89d05f34b 100644
--- a/drivers/spi/spi-dw.h
+++ b/drivers/spi/spi-dw.h
@@ -63,6 +63,7 @@
 #define DW_SPI_DR			0x60
 #define DW_SPI_RX_SAMPLE_DLY		0xf0
 #define DW_SPI_CS_OVERRIDE		0xf4
+#define DW_SPI_SPI_CTRLR0		0xf4
 
 /* Bit fields in CTRLR0 (DWC APB SSI) */
 #define DW_PSSI_CTRLR0_DFS_MASK			GENMASK(3, 0)
@@ -126,6 +127,12 @@
 #define DW_SPI_DMACR_RDMAE			BIT(0)
 #define DW_SPI_DMACR_TDMAE			BIT(1)
 
+/* Bit fields in SPI_CTRLR0 */
+#define DW_SPI_SPI_CTRLR0_CLK_STRETCH_EN	BIT(30)
+#define DW_SPI_SPI_CTRLR0_WAIT_CYCLE_MASK	GENMASK(15, 11)
+#define DW_SPI_SPI_CTRLR0_INST_L_MASK		GENMASK(9, 8)
+#define DW_SPI_SPI_CTRLR0_ADDR_L_MASK		GENMASK(5, 2)
+
 /* Mem/DMA operations helpers */
 #define DW_SPI_WAIT_RETRIES			5
 #define DW_SPI_BUF_SIZE \
@@ -141,6 +148,10 @@ struct dw_spi_cfg {
 	u32 ndf;
 	u32 freq;
 	u8 spi_frf;
+	u8 trans_t;
+	u8 inst_l;
+	u8 addr_l;
+	u8 wait_c;
 };
 
 struct dw_spi;
-- 
2.30.2