[PATCH AUTOSEL 5.5 01/41] spi: spi-omap2-mcspi: Handle DMA size restriction on AM65x

[PATCH AUTOSEL 5.5 01/41] spi: spi-omap2-mcspi: Handle DMA size restriction on AM65x

[Sasha Levin]

From: Vignesh Raghavendra <vigneshr-l0cyMroinI0@public.gmane.org>

[ Upstream commit e4e8276a4f652be2c7bb783a0155d4adb85f5d7d ]

On AM654, McSPI can only support 4K - 1 bytes per transfer when DMA is
enabled. Therefore populate master->max_transfer_size callback to
inform client drivers of this restriction when DMA channels are
available.

Signed-off-by: Vignesh Raghavendra <vigneshr-l0cyMroinI0@public.gmane.org>
Link: https://lore.kernel.org/r/20200204124816.16735-2-vigneshr-l0cyMroinI0@public.gmane.org
Signed-off-by: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/spi/spi-omap2-mcspi.c                 | 26 +++++++++++++++++++
 include/linux/platform_data/spi-omap2-mcspi.h |  1 +
 2 files changed, 27 insertions(+)

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 7e2292c11d120..e9bc9cf984d60 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -130,6 +130,7 @@ struct omap2_mcspi {
 	int			fifo_depth;
 	bool			slave_aborted;
 	unsigned int		pin_dir:1;
+	size_t			max_xfer_len;
 };
 
 struct omap2_mcspi_cs {
@@ -1305,6 +1306,18 @@ static bool omap2_mcspi_can_dma(struct spi_master *master,
 	return (xfer->len >= DMA_MIN_BYTES);
 }
 
+static size_t omap2_mcspi_max_xfer_size(struct spi_device *spi)
+{
+	struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master);
+	struct omap2_mcspi_dma *mcspi_dma =
+		&mcspi->dma_channels[spi->chip_select];
+
+	if (mcspi->max_xfer_len && mcspi_dma->dma_rx)
+		return mcspi->max_xfer_len;
+
+	return SIZE_MAX;
+}
+
 static int omap2_mcspi_controller_setup(struct omap2_mcspi *mcspi)
 {
 	struct spi_master	*master = mcspi->master;
@@ -1373,6 +1386,11 @@ static struct omap2_mcspi_platform_config omap4_pdata = {
 	.regs_offset = OMAP4_MCSPI_REG_OFFSET,
 };
 
+static struct omap2_mcspi_platform_config am654_pdata = {
+	.regs_offset = OMAP4_MCSPI_REG_OFFSET,
+	.max_xfer_len = SZ_4K - 1,
+};
+
 static const struct of_device_id omap_mcspi_of_match[] = {
 	{
 		.compatible = "ti,omap2-mcspi",
@@ -1382,6 +1400,10 @@ static const struct of_device_id omap_mcspi_of_match[] = {
 		.compatible = "ti,omap4-mcspi",
 		.data = &omap4_pdata,
 	},
+	{
+		.compatible = "ti,am654-mcspi",
+		.data = &am654_pdata,
+	},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, omap_mcspi_of_match);
@@ -1439,6 +1461,10 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
 		mcspi->pin_dir = pdata->pin_dir;
 	}
 	regs_offset = pdata->regs_offset;
+	if (pdata->max_xfer_len) {
+		mcspi->max_xfer_len = pdata->max_xfer_len;
+		master->max_transfer_size = omap2_mcspi_max_xfer_size;
+	}
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	mcspi->base = devm_ioremap_resource(&pdev->dev, r);
diff --git a/include/linux/platform_data/spi-omap2-mcspi.h b/include/linux/platform_data/spi-omap2-mcspi.h
index 0bf9fddb83064..3b400b1919a9b 100644
--- a/include/linux/platform_data/spi-omap2-mcspi.h
+++ b/include/linux/platform_data/spi-omap2-mcspi.h
@@ -11,6 +11,7 @@ struct omap2_mcspi_platform_config {
 	unsigned short	num_cs;
 	unsigned int regs_offset;
 	unsigned int pin_dir:1;
+	size_t max_xfer_len;
 };
 
 struct omap2_mcspi_device_config {
-- 
2.20.1

[PATCH AUTOSEL 5.5 02/41] spi: spi-omap2-mcspi: Support probe deferral for DMA channels

[Sasha Levin]

From: Vignesh Raghavendra <vigneshr@ti.com>

[ Upstream commit 32f2fc5dc3992b4b60cc6b1a6a31be605cc9c3a2 ]

dma_request_channel() can return -EPROBE_DEFER, if DMA driver is not
ready. Currently driver just falls back to PIO mode on probe deferral.
Fix this by requesting all required channels during probe and
propagating EPROBE_DEFER error code.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200204124816.16735-3-vigneshr@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-omap2-mcspi.c | 77 +++++++++++++++++------------------
 1 file changed, 38 insertions(+), 39 deletions(-)

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index e9bc9cf984d60..e9e256718ef4a 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -975,20 +975,12 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
  * Note that we currently allow DMA only if we get a channel
  * for both rx and tx. Otherwise we'll do PIO for both rx and tx.
  */
-static int omap2_mcspi_request_dma(struct spi_device *spi)
+static int omap2_mcspi_request_dma(struct omap2_mcspi *mcspi,
+				   struct omap2_mcspi_dma *mcspi_dma)
 {
-	struct spi_master	*master = spi->master;
-	struct omap2_mcspi	*mcspi;
-	struct omap2_mcspi_dma	*mcspi_dma;
 	int ret = 0;
 
-	mcspi = spi_master_get_devdata(master);
-	mcspi_dma = mcspi->dma_channels + spi->chip_select;
-
-	init_completion(&mcspi_dma->dma_rx_completion);
-	init_completion(&mcspi_dma->dma_tx_completion);
-
-	mcspi_dma->dma_rx = dma_request_chan(&master->dev,
+	mcspi_dma->dma_rx = dma_request_chan(mcspi->dev,
 					     mcspi_dma->dma_rx_ch_name);
 	if (IS_ERR(mcspi_dma->dma_rx)) {
 		ret = PTR_ERR(mcspi_dma->dma_rx);
@@ -996,7 +988,7 @@ static int omap2_mcspi_request_dma(struct spi_device *spi)
 		goto no_dma;
 	}
 
-	mcspi_dma->dma_tx = dma_request_chan(&master->dev,
+	mcspi_dma->dma_tx = dma_request_chan(mcspi->dev,
 					     mcspi_dma->dma_tx_ch_name);
 	if (IS_ERR(mcspi_dma->dma_tx)) {
 		ret = PTR_ERR(mcspi_dma->dma_tx);
@@ -1005,20 +997,40 @@ static int omap2_mcspi_request_dma(struct spi_device *spi)
 		mcspi_dma->dma_rx = NULL;
 	}
 
+	init_completion(&mcspi_dma->dma_rx_completion);
+	init_completion(&mcspi_dma->dma_tx_completion);
+
 no_dma:
 	return ret;
 }
 
+static void omap2_mcspi_release_dma(struct spi_master *master)
+{
+	struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
+	struct omap2_mcspi_dma	*mcspi_dma;
+	int i;
+
+	for (i = 0; i < master->num_chipselect; i++) {
+		mcspi_dma = &mcspi->dma_channels[i];
+
+		if (mcspi_dma->dma_rx) {
+			dma_release_channel(mcspi_dma->dma_rx);
+			mcspi_dma->dma_rx = NULL;
+		}
+		if (mcspi_dma->dma_tx) {
+			dma_release_channel(mcspi_dma->dma_tx);
+			mcspi_dma->dma_tx = NULL;
+		}
+	}
+}
+
 static int omap2_mcspi_setup(struct spi_device *spi)
 {
 	int			ret;
 	struct omap2_mcspi	*mcspi = spi_master_get_devdata(spi->master);
 	struct omap2_mcspi_regs	*ctx = &mcspi->ctx;
-	struct omap2_mcspi_dma	*mcspi_dma;
 	struct omap2_mcspi_cs	*cs = spi->controller_state;
 
-	mcspi_dma = &mcspi->dma_channels[spi->chip_select];
-
 	if (!cs) {
 		cs = kzalloc(sizeof *cs, GFP_KERNEL);
 		if (!cs)
@@ -1043,13 +1055,6 @@ static int omap2_mcspi_setup(struct spi_device *spi)
 		}
 	}
 
-	if (!mcspi_dma->dma_rx || !mcspi_dma->dma_tx) {
-		ret = omap2_mcspi_request_dma(spi);
-		if (ret)
-			dev_warn(&spi->dev, "not using DMA for McSPI (%d)\n",
-				 ret);
-	}
-
 	ret = pm_runtime_get_sync(mcspi->dev);
 	if (ret < 0) {
 		pm_runtime_put_noidle(mcspi->dev);
@@ -1066,12 +1071,8 @@ static int omap2_mcspi_setup(struct spi_device *spi)
 
 static void omap2_mcspi_cleanup(struct spi_device *spi)
 {
-	struct omap2_mcspi	*mcspi;
-	struct omap2_mcspi_dma	*mcspi_dma;
 	struct omap2_mcspi_cs	*cs;
 
-	mcspi = spi_master_get_devdata(spi->master);
-
 	if (spi->controller_state) {
 		/* Unlink controller state from context save list */
 		cs = spi->controller_state;
@@ -1080,19 +1081,6 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
 		kfree(cs);
 	}
 
-	if (spi->chip_select < spi->master->num_chipselect) {
-		mcspi_dma = &mcspi->dma_channels[spi->chip_select];
-
-		if (mcspi_dma->dma_rx) {
-			dma_release_channel(mcspi_dma->dma_rx);
-			mcspi_dma->dma_rx = NULL;
-		}
-		if (mcspi_dma->dma_tx) {
-			dma_release_channel(mcspi_dma->dma_tx);
-			mcspi_dma->dma_tx = NULL;
-		}
-	}
-
 	if (gpio_is_valid(spi->cs_gpio))
 		gpio_free(spi->cs_gpio);
 }
@@ -1303,6 +1291,9 @@ static bool omap2_mcspi_can_dma(struct spi_master *master,
 	if (spi_controller_is_slave(master))
 		return true;
 
+	master->dma_rx = mcspi_dma->dma_rx;
+	master->dma_tx = mcspi_dma->dma_tx;
+
 	return (xfer->len >= DMA_MIN_BYTES);
 }
 
@@ -1490,6 +1481,11 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
 	for (i = 0; i < master->num_chipselect; i++) {
 		sprintf(mcspi->dma_channels[i].dma_rx_ch_name, "rx%d", i);
 		sprintf(mcspi->dma_channels[i].dma_tx_ch_name, "tx%d", i);
+
+		status = omap2_mcspi_request_dma(mcspi,
+						 &mcspi->dma_channels[i]);
+		if (status == -EPROBE_DEFER)
+			goto free_master;
 	}
 
 	status = platform_get_irq(pdev, 0);
@@ -1527,6 +1523,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 free_master:
+	omap2_mcspi_release_dma(master);
 	spi_master_put(master);
 	return status;
 }
@@ -1536,6 +1533,8 @@ static int omap2_mcspi_remove(struct platform_device *pdev)
 	struct spi_master *master = platform_get_drvdata(pdev);
 	struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
 
+	omap2_mcspi_release_dma(master);
+
 	pm_runtime_dont_use_autosuspend(mcspi->dev);
 	pm_runtime_put_sync(mcspi->dev);
 	pm_runtime_disable(&pdev->dev);
-- 
2.20.1

[PATCH AUTOSEL 5.5 10/41] spi: qup: call spi_qup_pm_resume_runtime before suspending

[Sasha Levin]

From: Yuji Sasaki <sasakiy@chromium.org>

[ Upstream commit 136b5cd2e2f97581ae560cff0db2a3b5369112da ]

spi_qup_suspend() will cause synchronous external abort when
runtime suspend is enabled and applied, as it tries to
access SPI controller register while clock is already disabled
in spi_qup_pm_suspend_runtime().

Signed-off-by: Yuji sasaki <sasakiy@chromium.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20200214074340.2286170-1-vkoul@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-qup.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index dd3434a407ea6..a364b99497e26 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -1217,6 +1217,11 @@ static int spi_qup_suspend(struct device *device)
 	struct spi_qup *controller = spi_master_get_devdata(master);
 	int ret;
 
+	if (pm_runtime_suspended(device)) {
+		ret = spi_qup_pm_resume_runtime(device);
+		if (ret)
+			return ret;
+	}
 	ret = spi_master_suspend(master);
 	if (ret)
 		return ret;
@@ -1225,10 +1230,8 @@ static int spi_qup_suspend(struct device *device)
 	if (ret)
 		return ret;
 
-	if (!pm_runtime_suspended(device)) {
-		clk_disable_unprepare(controller->cclk);
-		clk_disable_unprepare(controller->iclk);
-	}
+	clk_disable_unprepare(controller->cclk);
+	clk_disable_unprepare(controller->iclk);
 	return 0;
 }
 
-- 
2.20.1

[PATCH AUTOSEL 5.5 15/41] spi: pxa2xx: Add CS control clock quirk

[Sasha Levin]

From: Evan Green <evgreen@chromium.org>

[ Upstream commit 683f65ded66a9a7ff01ed7280804d2132ebfdf7e ]

In some circumstances on Intel LPSS controllers, toggling the LPSS
CS control register doesn't actually cause the CS line to toggle.
This seems to be failure of dynamic clock gating that occurs after
going through a suspend/resume transition, where the controller
is sent through a reset transition. This ruins SPI transactions
that either rely on delay_usecs, or toggle the CS line without
sending data.

Whenever CS is toggled, momentarily set the clock gating register
to "Force On" to poke the controller into acting on CS.

Signed-off-by: Rajat Jain <rajatja@google.com>
Signed-off-by: Evan Green <evgreen@chromium.org>
Link: https://lore.kernel.org/r/20200211223700.110252-1-rajatja@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-pxa2xx.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index 9071333ebdd86..cabd1a85d71e3 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -70,6 +70,10 @@ MODULE_ALIAS("platform:pxa2xx-spi");
 #define LPSS_CAPS_CS_EN_SHIFT			9
 #define LPSS_CAPS_CS_EN_MASK			(0xf << LPSS_CAPS_CS_EN_SHIFT)
 
+#define LPSS_PRIV_CLOCK_GATE 0x38
+#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3
+#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3
+
 struct lpss_config {
 	/* LPSS offset from drv_data->ioaddr */
 	unsigned offset;
@@ -86,6 +90,8 @@ struct lpss_config {
 	unsigned cs_sel_shift;
 	unsigned cs_sel_mask;
 	unsigned cs_num;
+	/* Quirks */
+	unsigned cs_clk_stays_gated : 1;
 };
 
 /* Keep these sorted with enum pxa_ssp_type */
@@ -156,6 +162,7 @@ static const struct lpss_config lpss_platforms[] = {
 		.tx_threshold_hi = 56,
 		.cs_sel_shift = 8,
 		.cs_sel_mask = 3 << 8,
+		.cs_clk_stays_gated = true,
 	},
 };
 
@@ -383,6 +390,22 @@ static void lpss_ssp_cs_control(struct spi_device *spi, bool enable)
 	else
 		value |= LPSS_CS_CONTROL_CS_HIGH;
 	__lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
+	if (config->cs_clk_stays_gated) {
+		u32 clkgate;
+
+		/*
+		 * Changing CS alone when dynamic clock gating is on won't
+		 * actually flip CS at that time. This ruins SPI transfers
+		 * that specify delays, or have no data. Toggle the clock mode
+		 * to force on briefly to poke the CS pin to move.
+		 */
+		clkgate = __lpss_ssp_read_priv(drv_data, LPSS_PRIV_CLOCK_GATE);
+		value = (clkgate & ~LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK) |
+			LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON;
+
+		__lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, value);
+		__lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, clkgate);
+	}
 }
 
 static void cs_assert(struct spi_device *spi)
-- 
2.20.1

[PATCH AUTOSEL 5.5 16/41] spi/zynqmp: remove entry that causes a cs glitch

[Sasha Levin]

From: Thommy Jakobsson <thommyj@gmail.com>

[ Upstream commit 5dd8304981ecffa77bb72b1c57c4be5dfe6cfae9 ]

In the public interface for chipselect, there is always an entry
commented as "Dummy generic FIFO entry" pushed down to the fifo right
after the activate/deactivate command. The dummy entry is 0x0,
irregardless if the intention was to activate or deactive the cs. This
causes the cs line to glitch rather than beeing activated in the case
when there was an activate command.

This has been observed on oscilloscope, and have caused problems for at
least one specific flash device type connected to the qspi port. After
the change the glitch is gone and cs goes active when intended.

The reason why this worked before (except for the glitch) was because
when sending the actual data, the CS bits are once again set. Since
most flashes uses mode 0, there is always a half clk period anyway for
cs to clk active setup time. If someone would rely on timing from a
chip_select call to a transfer_one, it would fail though.

It is unknown why the dummy entry was there in the first place, git log
seems to be of no help in this case. The reference manual gives no
indication of the necessity of this. In fact the lower 8 bits are a
setup (or hold in case of deactivate) time expressed in cycles. So this
should not be needed to fulfill any setup/hold timings.

Signed-off-by: Thommy Jakobsson <thommyj@gmail.com>
Reviewed-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
Link: https://lore.kernel.org/r/20200224162643.29102-1-thommyj@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-zynqmp-gqspi.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index 60c4de4e44856..7412a3042a8d2 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -401,9 +401,6 @@ static void zynqmp_qspi_chipselect(struct spi_device *qspi, bool is_high)
 
 	zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST, genfifoentry);
 
-	/* Dummy generic FIFO entry */
-	zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST, 0x0);
-
 	/* Manually start the generic FIFO command */
 	zynqmp_gqspi_write(xqspi, GQSPI_CONFIG_OFST,
 			zynqmp_gqspi_read(xqspi, GQSPI_CONFIG_OFST) |
-- 
2.20.1

[PATCH AUTOSEL 5.5 30/41] spi: spi_register_controller(): free bus id on error paths

[Sasha Levin]

From: Aaro Koskinen <aaro.koskinen@nokia.com>

[ Upstream commit f9981d4f50b475d7dbb70f3022b87a3c8bba9fd6 ]

Some error paths leave the bus id allocated. As a result the IDR
allocation will fail after a deferred probe. Fix by freeing the bus id
always on error.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Message-Id: <20200304111740.27915-1-aaro.koskinen@nokia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 8994545367a2d..0e70af2677fee 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2615,7 +2615,7 @@ int spi_register_controller(struct spi_controller *ctlr)
 		if (ctlr->use_gpio_descriptors) {
 			status = spi_get_gpio_descs(ctlr);
 			if (status)
-				return status;
+				goto free_bus_id;
 			/*
 			 * A controller using GPIO descriptors always
 			 * supports SPI_CS_HIGH if need be.
@@ -2625,7 +2625,7 @@ int spi_register_controller(struct spi_controller *ctlr)
 			/* Legacy code path for GPIOs from DT */
 			status = of_spi_get_gpio_numbers(ctlr);
 			if (status)
-				return status;
+				goto free_bus_id;
 		}
 	}
 
@@ -2633,17 +2633,14 @@ int spi_register_controller(struct spi_controller *ctlr)
 	 * Even if it's just one always-selected device, there must
 	 * be at least one chipselect.
 	 */
-	if (!ctlr->num_chipselect)
-		return -EINVAL;
+	if (!ctlr->num_chipselect) {
+		status = -EINVAL;
+		goto free_bus_id;
+	}
 
 	status = device_add(&ctlr->dev);
-	if (status < 0) {
-		/* free bus id */
-		mutex_lock(&board_lock);
-		idr_remove(&spi_master_idr, ctlr->bus_num);
-		mutex_unlock(&board_lock);
-		goto done;
-	}
+	if (status < 0)
+		goto free_bus_id;
 	dev_dbg(dev, "registered %s %s\n",
 			spi_controller_is_slave(ctlr) ? "slave" : "master",
 			dev_name(&ctlr->dev));
@@ -2659,11 +2656,7 @@ int spi_register_controller(struct spi_controller *ctlr)
 		status = spi_controller_initialize_queue(ctlr);
 		if (status) {
 			device_del(&ctlr->dev);
-			/* free bus id */
-			mutex_lock(&board_lock);
-			idr_remove(&spi_master_idr, ctlr->bus_num);
-			mutex_unlock(&board_lock);
-			goto done;
+			goto free_bus_id;
 		}
 	}
 	/* add statistics */
@@ -2678,7 +2671,12 @@ int spi_register_controller(struct spi_controller *ctlr)
 	/* Register devices from the device tree and ACPI */
 	of_register_spi_devices(ctlr);
 	acpi_register_spi_devices(ctlr);
-done:
+	return status;
+
+free_bus_id:
+	mutex_lock(&board_lock);
+	idr_remove(&spi_master_idr, ctlr->bus_num);
+	mutex_unlock(&board_lock);
 	return status;
 }
 EXPORT_SYMBOL_GPL(spi_register_controller);
-- 
2.20.1

Re: [PATCH AUTOSEL 5.5 01/41] spi: spi-omap2-mcspi: Handle DMA size restriction on AM65x

[Mark Brown]

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On Sun, Mar 15, 2020 at 10:32:39PM -0400, Sasha Levin wrote:
> From: Vignesh Raghavendra <vigneshr-l0cyMroinI0@public.gmane.org>
> 
> [ Upstream commit e4e8276a4f652be2c7bb783a0155d4adb85f5d7d ]
> 
> On AM654, McSPI can only support 4K - 1 bytes per transfer when DMA is
> enabled. Therefore populate master->max_transfer_size callback to
> inform client drivers of this restriction when DMA channels are
> available.

As ever this only provides information to other drivers which may be
buggy.

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Re: [PATCH AUTOSEL 5.5 01/41] spi: spi-omap2-mcspi: Handle DMA size restriction on AM65x

[Sasha Levin]

On Mon, Mar 16, 2020 at 11:50:57AM +0000, Mark Brown wrote:
>On Sun, Mar 15, 2020 at 10:32:39PM -0400, Sasha Levin wrote:
>> From: Vignesh Raghavendra <vigneshr-l0cyMroinI0@public.gmane.org>
>>
>> [ Upstream commit e4e8276a4f652be2c7bb783a0155d4adb85f5d7d ]
>>
>> On AM654, McSPI can only support 4K - 1 bytes per transfer when DMA is
>> enabled. Therefore populate master->max_transfer_size callback to
>> inform client drivers of this restriction when DMA channels are
>> available.
>
>As ever this only provides information to other drivers which may be
>buggy.

I'll drop it, thanks!

-- 
Thanks,
Sasha