[PATCH v3 0/3] microchip core-qspi gpio-cs fixes + cleanup

[PATCH v3 0/3] microchip core-qspi gpio-cs fixes + cleanup

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Hey Mark,

v3 with the review comment about the core handing CS_HIGH dealt with.
I noticed that in the same function there was a "raw" BIT(1), which I
replaced with a macro that the patch was already adding for use in the
setup function...

Cheers,
Conor.

CC: Conor Dooley <conor.dooley@microchip.com>
CC: Daire McNamara <daire.mcnamara@microchip.com>
CC: Mark Brown <broonie@kernel.org>
CC: Cyril Jean <cyril.jean@microchip.com>
CC: Valentina.FernandezAlanis@microchip.com
CC: linux-riscv@lists.infradead.org
CC: linux-spi@vger.kernel.org
CC: linux-kernel@vger.kernel.org

Conor Dooley (3):
  spi: microchip-core-qspi: control built-in cs manually
  spi: microchip-core-qspi: don't attempt to transmit during emulated
    read-only dual/quad operations
  spi: microchip-core-qspi: remove some inline markings

 drivers/spi/spi-microchip-core-qspi.c | 99 +++++++++++++++++++++------
 1 file changed, 79 insertions(+), 20 deletions(-)

-- 
2.53.0

[PATCH v3 1/3] spi: microchip-core-qspi: control built-in cs manually

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

The coreQSPI IP supports only a single chip select, which is
automagically operated by the hardware - set low when the transmit
buffer first gets written to and set high when the number of bytes
written to the TOTALBYTES field of the FRAMES register have been sent on
the bus. Additional devices must use GPIOs for their chip selects.
It was reported to me that if there are two devices attached to this
QSPI controller that the in-built chip select is set low while linux
tries to access the device attached to the GPIO.

This went undetected as the boards that connected multiple devices to
the SPI controller all exclusively used GPIOs for chip selects, not
relying on the built-in chip select at all. It turns out that this was
because the built-in chip select, when controlled automagically, is set
low when active and high when inactive, thereby ruling out its use for
active-high devices or devices that need to transmit with the chip
select disabled.

Modify the driver so that it controls chip select directly, retaining
the behaviour for mem_ops of setting the chip select active for the
entire duration of the transfer in the exec_op callback. For regular
transfers, implement the set_cs callback for the core to use.

As part of this, the existing setup callback, mchp_coreqspi_setup_op(),
is removed. Modifying the CLKIDLE field is not safe to do during
operation when there are multiple devices, so this code is removed
entirely. Setting the MASTER and ENABLE fields is something that can be
done once at probe, it doesn't need to be re-run for each device.
Instead the new setup callback sets the built-in chip select to its
inactive state for active-low devices, as the reset value of the chip
select in software controlled mode is low.

Fixes: 8f9cf02c88528 ("spi: microchip-core-qspi: Add regular transfers")
Fixes: 8596124c4c1bc ("spi: microchip-core-qspi: Add support for microchip fpga qspi controllers")
CC: stable@vger.kernel.org
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/spi/spi-microchip-core-qspi.c | 79 ++++++++++++++++++++++-----
 1 file changed, 64 insertions(+), 15 deletions(-)

diff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c
index eab059fb0bc2c..ffa0f33a0ae09 100644
--- a/drivers/spi/spi-microchip-core-qspi.c
+++ b/drivers/spi/spi-microchip-core-qspi.c
@@ -74,6 +74,13 @@
 #define STATUS_FLAGSX4		BIT(8)
 #define STATUS_MASK		GENMASK(8, 0)
 
+/*
+ * QSPI Direct Access register defines
+ */
+#define DIRECT_ACCESS_EN_SSEL		BIT(0)
+#define DIRECT_ACCESS_OP_SSEL		BIT(1)
+#define DIRECT_ACCESS_OP_SSEL_SHIFT	1
+
 #define BYTESUPPER_MASK		GENMASK(31, 16)
 #define BYTESLOWER_MASK		GENMASK(15, 0)
 
@@ -158,6 +165,38 @@ static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_m
 	return 0;
 }
 
+static void mchp_coreqspi_set_cs(struct spi_device *spi, bool enable)
+{
+	struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller);
+	u32 val;
+
+	val = readl(qspi->regs + REG_DIRECT_ACCESS);
+
+	val &= ~DIRECT_ACCESS_OP_SSEL;
+	val |= !enable << DIRECT_ACCESS_OP_SSEL_SHIFT;
+
+	writel(val, qspi->regs + REG_DIRECT_ACCESS);
+}
+
+static int mchp_coreqspi_setup(struct spi_device *spi)
+{
+	struct mchp_coreqspi *qspi = spi_controller_get_devdata(spi->controller);
+	u32 val;
+
+	/*
+	 * Active low devices need to be specifically set to their inactive
+	 * states during probe.
+	 */
+	if (spi->mode & SPI_CS_HIGH)
+		return 0;
+
+	val = readl(qspi->regs + REG_DIRECT_ACCESS);
+	val |= DIRECT_ACCESS_OP_SSEL;
+	writel(val, qspi->regs + REG_DIRECT_ACCESS);
+
+	return 0;
+}
+
 static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi)
 {
 	u32 control, data;
@@ -380,19 +419,6 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi
 	return 0;
 }
 
-static int mchp_coreqspi_setup_op(struct spi_device *spi_dev)
-{
-	struct spi_controller *ctlr = spi_dev->controller;
-	struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr);
-	u32 control = readl_relaxed(qspi->regs + REG_CONTROL);
-
-	control |= (CONTROL_MASTER | CONTROL_ENABLE);
-	control &= ~CONTROL_CLKIDLE;
-	writel_relaxed(control, qspi->regs + REG_CONTROL);
-
-	return 0;
-}
-
 static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op)
 {
 	u32 idle_cycles = 0;
@@ -483,6 +509,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
 
 	reinit_completion(&qspi->data_completion);
 	mchp_coreqspi_config_op(qspi, op);
+	mchp_coreqspi_set_cs(mem->spi, true);
 	if (op->cmd.opcode) {
 		qspi->txbuf = &opcode;
 		qspi->rxbuf = NULL;
@@ -523,6 +550,7 @@ static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
 		err = -ETIMEDOUT;
 
 error:
+	mchp_coreqspi_set_cs(mem->spi, false);
 	mutex_unlock(&qspi->op_lock);
 	mchp_coreqspi_disable_ints(qspi);
 
@@ -686,6 +714,7 @@ static int mchp_coreqspi_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	int ret;
+	u32 num_cs, val;
 
 	ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*qspi));
 	if (!ctlr)
@@ -718,10 +747,18 @@ static int mchp_coreqspi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/*
+	 * The IP core only has a single CS, any more have to be provided via
+	 * gpios
+	 */
+	if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs))
+		num_cs = 1;
+
+	ctlr->num_chipselect = num_cs;
+
 	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
 	ctlr->mem_ops = &mchp_coreqspi_mem_ops;
 	ctlr->mem_caps = &mchp_coreqspi_mem_caps;
-	ctlr->setup = mchp_coreqspi_setup_op;
 	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD |
 			  SPI_TX_DUAL | SPI_TX_QUAD;
 	ctlr->dev.of_node = np;
@@ -729,9 +766,21 @@ static int mchp_coreqspi_probe(struct platform_device *pdev)
 	ctlr->prepare_message = mchp_coreqspi_prepare_message;
 	ctlr->unprepare_message = mchp_coreqspi_unprepare_message;
 	ctlr->transfer_one = mchp_coreqspi_transfer_one;
-	ctlr->num_chipselect = 2;
+	ctlr->setup = mchp_coreqspi_setup;
+	ctlr->set_cs = mchp_coreqspi_set_cs;
 	ctlr->use_gpio_descriptors = true;
 
+	val = readl_relaxed(qspi->regs + REG_CONTROL);
+	val |= (CONTROL_MASTER | CONTROL_ENABLE);
+	writel_relaxed(val, qspi->regs + REG_CONTROL);
+
+	/*
+	 * Put cs into software controlled mode
+	 */
+	val = readl_relaxed(qspi->regs + REG_DIRECT_ACCESS);
+	val |= DIRECT_ACCESS_EN_SSEL;
+	writel(val, qspi->regs + REG_DIRECT_ACCESS);
+
 	ret = spi_register_controller(ctlr);
 	if (ret)
 		return dev_err_probe(&pdev->dev, ret,
-- 
2.53.0

[PATCH v3 2/3] spi: microchip-core-qspi: don't attempt to transmit during emulated read-only dual/quad operations

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

The core will deal with reads by creating clock cycles itself, there's
no need to generate clock cycles by transmitting garbage data at the
driver level. Further, transmitting garbage data just bricks the transfer
since QSPI doesn't have a dedicated master-out line like MOSI in regular
SPI. I'm not entirely sure if the transfer is bricked because of the
garbage data being transmitted on the bus or because the core loses
track of whether it is supposed to be sending or receiving data.

Fixes: 8f9cf02c88528 ("spi: microchip-core-qspi: Add regular transfers")
CC: stable@vger.kernel.org
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/spi/spi-microchip-core-qspi.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c
index ffa0f33a0ae09..70215a407b5a3 100644
--- a/drivers/spi/spi-microchip-core-qspi.c
+++ b/drivers/spi/spi-microchip-core-qspi.c
@@ -690,18 +690,28 @@ static int mchp_coreqspi_transfer_one(struct spi_controller *ctlr, struct spi_de
 				      struct spi_transfer *t)
 {
 	struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr);
+	bool dual_quad = false;
 
 	qspi->tx_len = t->len;
 
+	if (t->tx_nbits == SPI_NBITS_QUAD || t->rx_nbits == SPI_NBITS_QUAD ||
+			t->tx_nbits == SPI_NBITS_DUAL ||
+			t->rx_nbits == SPI_NBITS_DUAL)
+		dual_quad = true;
+
 	if (t->tx_buf)
 		qspi->txbuf = (u8 *)t->tx_buf;
 
 	if (!t->rx_buf) {
 		mchp_coreqspi_write_op(qspi);
-	} else {
+	} else if (!dual_quad) {
 		qspi->rxbuf = (u8 *)t->rx_buf;
 		qspi->rx_len = t->len;
 		mchp_coreqspi_write_read_op(qspi);
+	} else {
+		qspi->rxbuf = (u8 *)t->rx_buf;
+		qspi->rx_len = t->len;
+		mchp_coreqspi_read_op(qspi);
 	}
 
 	return 0;
-- 
2.53.0

[PATCH v3 3/3] spi: microchip-core-qspi: remove some inline markings

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Remove inline markings from a number of functions that are called as
part of mem ops callbacks. None of them are either particularly trivial
or sensitive to overhead of a function call. Just let the compiler
decide what to do with them.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/spi/spi-microchip-core-qspi.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c
index 70215a407b5a3..4dee0fea1df8d 100644
--- a/drivers/spi/spi-microchip-core-qspi.c
+++ b/drivers/spi/spi-microchip-core-qspi.c
@@ -197,7 +197,7 @@ static int mchp_coreqspi_setup(struct spi_device *spi)
 	return 0;
 }
 
-static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi)
+static void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi)
 {
 	u32 control, data;
 
@@ -233,7 +233,7 @@ static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi)
 	}
 }
 
-static inline void mchp_coreqspi_write_op(struct mchp_coreqspi *qspi)
+static void mchp_coreqspi_write_op(struct mchp_coreqspi *qspi)
 {
 	u32 control, data;
 
@@ -261,7 +261,7 @@ static inline void mchp_coreqspi_write_op(struct mchp_coreqspi *qspi)
 	}
 }
 
-static inline void mchp_coreqspi_write_read_op(struct mchp_coreqspi *qspi)
+static void mchp_coreqspi_write_read_op(struct mchp_coreqspi *qspi)
 {
 	u32 control, data;
 
@@ -419,7 +419,7 @@ static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_devi
 	return 0;
 }
 
-static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op)
+static void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op)
 {
 	u32 idle_cycles = 0;
 	int total_bytes, cmd_bytes, frames, ctrl;
-- 
2.53.0

Re: [PATCH v3 0/3] microchip core-qspi gpio-cs fixes + cleanup

[Mark Brown]

On Thu, 30 Apr 2026 11:10:17 +0100, Conor Dooley wrote:
> microchip core-qspi gpio-cs fixes + cleanup
> 
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Hey Mark,
> 
> v3 with the review comment about the core handing CS_HIGH dealt with.
> I noticed that in the same function there was a "raw" BIT(1), which I
> replaced with a macro that the patch was already adding for use in the
> setup function...
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-7.1

Thanks!

[1/3] spi: microchip-core-qspi: control built-in cs manually
      https://git.kernel.org/broonie/spi/c/7672749e1496
[2/3] spi: microchip-core-qspi: don't attempt to transmit during emulated read-only dual/quad operations
      https://git.kernel.org/broonie/spi/c/eb56deaabf12
[3/3] spi: microchip-core-qspi: remove some inline markings
      https://git.kernel.org/broonie/spi/c/0b2eb1f8473e

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark