[PATCH v2 0/5] K2G: Add QSPI support

[PATCH v2 0/5] K2G: Add QSPI support

[Vignesh R]

This series adds support for Cadence QSPI IP present in TI's 66AK2G SoC.
The patches enhance the existing cadence-quadspi driver to support
loopback clock circuit, pm_runtime support and tweaks for 66AK2G SoC.


Changes in v2:
* Drop DT patches. Will be sent as separate series as requested by
 maintainer.
* Split binding docs into separate patches.
* Address comments by Rob Herring.

Vignesh R (5):
  mtd: spi-nor: cadence-quadspi: Add TI 66AK2G SoC specific compatible
  mtd: spi-nor: cadence-quadspi: add a delay in write sequence
  mtd: spi-nor: cadence-quadspi: Add new binding to enable loop-back
    circuit
  mtd: spi-nor: cadence-quadspi: Add support to enable loop-back clock
    circuit
  mtd: spi-nor: cadence-quadspi: Add runtime PM support

 .../devicetree/bindings/mtd/cadence-quadspi.txt    |  7 +++-
 drivers/mtd/spi-nor/cadence-quadspi.c              | 46 ++++++++++++++++++++--
 2 files changed, 49 insertions(+), 4 deletions(-)

-- 
2.14.1

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[PATCH v2 1/5] mtd: spi-nor: cadence-quadspi: Add TI 66AK2G SoC specific compatible

[Vignesh R]

Update binding documentation to add a new compatible for TI 66AK2G SoC,
to handle TI SoC specific quirks in the driver.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 Documentation/devicetree/bindings/mtd/cadence-quadspi.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
index f248056da24c..7dbe3bd9ac56 100644
--- a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
+++ b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
@@ -1,7 +1,9 @@
 * Cadence Quad SPI controller
 
 Required properties:
-- compatible : Should be "cdns,qspi-nor".
+- compatible : should be one of the following:
+	Generic default - "cdns,qspi-nor".
+	For TI 66AK2G SoC - "ti,k2g-qspi", "cdns,qspi-nor".
 - reg : Contains two entries, each of which is a tuple consisting of a
 	physical address and length. The first entry is the address and
 	length of the controller register set. The second entry is the
-- 
2.14.1

[PATCH v2 2/5] mtd: spi-nor: cadence-quadspi: add a delay in write sequence

[Vignesh R]

As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
Controller programming sequence, a delay equal to couple of QSPI master
clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
writing data to the flash. Introduce a quirk flag CQSPI_NEEDS_WR_DELAY
to handle this and set this flag for TI 66AK2G SoC.

[1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
v2:
Split binding doc to separate patch
Use data pointer to indicate write delay.

 drivers/mtd/spi-nor/cadence-quadspi.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 53c7d8e0327a..bb0cb02a6938 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -38,6 +38,9 @@
 #define CQSPI_NAME			"cadence-qspi"
 #define CQSPI_MAX_CHIPSELECT		16
 
+/* Quirks */
+#define CQSPI_NEEDS_WR_DELAY		BIT(0)
+
 struct cqspi_st;
 
 struct cqspi_flash_pdata {
@@ -76,6 +79,7 @@ struct cqspi_st {
 	u32			fifo_depth;
 	u32			fifo_width;
 	u32			trigger_address;
+	u32			wr_delay;
 	struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
 };
 
@@ -608,6 +612,15 @@ static int cqspi_indirect_write_execute(struct spi_nor *nor,
 	reinit_completion(&cqspi->transfer_complete);
 	writel(CQSPI_REG_INDIRECTWR_START_MASK,
 	       reg_base + CQSPI_REG_INDIRECTWR);
+	/*
+	 * As per 66AK2G02 TRM SPRUHY8F section 11.15.5.3 Indirect Access
+	 * Controller programming sequence, couple of cycles of
+	 * QSPI_REF_CLK delay is required for the above bit to
+	 * be internally synchronized by the QSPI module. Provide 5
+	 * cycles of delay.
+	 */
+	if (cqspi->wr_delay)
+		ndelay(cqspi->wr_delay);
 
 	while (remaining > 0) {
 		write_bytes = remaining > page_size ? page_size : remaining;
@@ -1156,6 +1169,7 @@ static int cqspi_probe(struct platform_device *pdev)
 	struct cqspi_st *cqspi;
 	struct resource *res;
 	struct resource *res_ahb;
+	u32 data;
 	int ret;
 	int irq;
 
@@ -1213,6 +1227,10 @@ static int cqspi_probe(struct platform_device *pdev)
 	}
 
 	cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
+	data  = (u32)of_device_get_match_data(&pdev->dev);
+	if (data & CQSPI_NEEDS_WR_DELAY)
+		cqspi->wr_delay = 5 * DIV_ROUND_UP(NSEC_PER_SEC,
+						   cqspi->master_ref_clk_hz);
 
 	ret = devm_request_irq(dev, irq, cqspi_irq_handler, 0,
 			       pdev->name, cqspi);
@@ -1284,7 +1302,14 @@ static const struct dev_pm_ops cqspi__dev_pm_ops = {
 #endif
 
 static const struct of_device_id cqspi_dt_ids[] = {
-	{.compatible = "cdns,qspi-nor",},
+	{
+		.compatible = "cdns,qspi-nor",
+		.data = (void *)0,
+	},
+	{
+		.compatible = "ti,k2g-qspi",
+		.data = (void *)CQSPI_NEEDS_WR_DELAY,
+	},
 	{ /* end of table */ }
 };
 
-- 
2.14.1

[PATCH v2 3/5] mtd: spi-nor: cadence-quadspi: Add new binding to enable loop-back circuit

[Vignesh R]

Cadence QSPI IP has a adapted loop-back circuit which can be enabled by
setting BYPASS field to 0 in READCAPTURE register. It enables use of
QSPI return clock to latch the data rather than the internal QSPI
reference clock. For high speed operations, adapted loop-back circuit
using QSPI return clock helps to increase data valid window.

Add DT parameter cdns,rclk-en to help enable adapted loop-back circuit
for boards which do have QSPI return clock provided. Update binding
documentation for the same.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 Documentation/devicetree/bindings/mtd/cadence-quadspi.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
index 7dbe3bd9ac56..bb2075df9b38 100644
--- a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
+++ b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
@@ -16,6 +16,9 @@ Required properties:
 
 Optional properties:
 - cdns,is-decoded-cs : Flag to indicate whether decoder is used or not.
+- cdns,rclk-en : Flag to indicate that QSPI return clock is used to latch
+  the read data rather than the QSPI clock. Make sure that QSPI return
+  clock is populated on the board before using this property.
 
 Optional subnodes:
 Subnodes of the Cadence Quad SPI controller are spi slave nodes with additional
-- 
2.14.1

[PATCH v2 4/5] mtd: spi-nor: cadence-quadspi: Add support to enable loop-back clock circuit

[Vignesh R]

Cadence QSPI IP has a adapted loop-back circuit which can be enabled by
setting BYPASS field to 0 in READCAPTURE register. It enables use of
QSPI return clock to latch the data rather than the internal QSPI
reference clock. For high speed operations, adapted loop-back circuit
using QSPI return clock helps to increase data valid window.

Based on DT parameter cdns,rclk-en enable adapted loop-back circuit
for boards which do have QSPI return clock provided.
This patch also modifies cqspi_readdata_capture() function's bypass
parameter to bool to match how its used in the function.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---

v2:
Split doc update to separate patch

 drivers/mtd/spi-nor/cadence-quadspi.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index bb0cb02a6938..c11ced529ddd 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -78,6 +78,7 @@ struct cqspi_st {
 	bool			is_decoded_cs;
 	u32			fifo_depth;
 	u32			fifo_width;
+	bool			rclk_en;
 	u32			trigger_address;
 	u32			wr_delay;
 	struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
@@ -788,7 +789,7 @@ static void cqspi_config_baudrate_div(struct cqspi_st *cqspi)
 }
 
 static void cqspi_readdata_capture(struct cqspi_st *cqspi,
-				   const unsigned int bypass,
+				   const bool bypass,
 				   const unsigned int delay)
 {
 	void __iomem *reg_base = cqspi->iobase;
@@ -852,7 +853,8 @@ static void cqspi_configure(struct spi_nor *nor)
 		cqspi->sclk = sclk;
 		cqspi_config_baudrate_div(cqspi);
 		cqspi_delay(nor);
-		cqspi_readdata_capture(cqspi, 1, f_pdata->read_delay);
+		cqspi_readdata_capture(cqspi, !cqspi->rclk_en,
+				       f_pdata->read_delay);
 	}
 
 	if (switch_cs || switch_ck)
@@ -1049,6 +1051,8 @@ static int cqspi_of_get_pdata(struct platform_device *pdev)
 		return -ENXIO;
 	}
 
+	cqspi->rclk_en = of_property_read_bool(np, "cdns,rclk-en");
+
 	return 0;
 }
 
-- 
2.14.1

[PATCH v2 5/5] mtd: spi-nor: cadence-quadspi: Add runtime PM support

[Vignesh R]

Add pm_runtime* calls to cadence-quadspi driver. This is required to
switch on QSPI power domain on TI 66AK2G SoC during probe.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 drivers/mtd/spi-nor/cadence-quadspi.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index c11ced529ddd..4fd6fb9c83b3 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -31,6 +31,7 @@
 #include <linux/of_device.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/sched.h>
 #include <linux/spi/spi.h>
 #include <linux/timer.h>
@@ -1224,6 +1225,13 @@ static int cqspi_probe(struct platform_device *pdev)
 		return -ENXIO;
 	}
 
+	pm_runtime_enable(&pdev->dev);
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(&pdev->dev);
+		return ret;
+	}
+
 	ret = clk_prepare_enable(cqspi->clk);
 	if (ret) {
 		dev_err(dev, "Cannot enable QSPI clock.\n");
@@ -1275,6 +1283,9 @@ static int cqspi_remove(struct platform_device *pdev)
 
 	clk_disable_unprepare(cqspi->clk);
 
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
 	return 0;
 }
 
-- 
2.14.1

Re: [PATCH v2 1/5] mtd: spi-nor: cadence-quadspi: Add TI 66AK2G SoC specific compatible

[Rob Herring]

On Wed, Aug 16, 2017 at 10:20:49AM +0530, Vignesh R wrote:
> Update binding documentation to add a new compatible for TI 66AK2G SoC,
> to handle TI SoC specific quirks in the driver.
> 
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
>  Documentation/devicetree/bindings/mtd/cadence-quadspi.txt | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v2 3/5] mtd: spi-nor: cadence-quadspi: Add new binding to enable loop-back circuit

[Rob Herring]

On Wed, Aug 16, 2017 at 10:20:51AM +0530, Vignesh R wrote:
> Cadence QSPI IP has a adapted loop-back circuit which can be enabled by
> setting BYPASS field to 0 in READCAPTURE register. It enables use of
> QSPI return clock to latch the data rather than the internal QSPI
> reference clock. For high speed operations, adapted loop-back circuit
> using QSPI return clock helps to increase data valid window.
> 
> Add DT parameter cdns,rclk-en to help enable adapted loop-back circuit
> for boards which do have QSPI return clock provided. Update binding
> documentation for the same.
> 
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
>  Documentation/devicetree/bindings/mtd/cadence-quadspi.txt | 3 +++
>  1 file changed, 3 insertions(+)

Acked-by: Rob Herring <robh@kernel.org>