[PATCH 0/7] atmel-spi: Allow using more than 4 GPIOs as CS

[PATCH 0/7] atmel-spi: Allow using more than 4 GPIOs as CS

[Gregory CLEMENT]

Hello,

the main purpose of this series is allowing to use more than 4 GPIOs
as CS. But while doing it, I also clean-up the code and the comments
to match the actual support of the hardware.

Thanks to this series, it is now more clear to see what can be done
with CS GPIO and native CS. It is also possible to mix native and GPIO
CS as expected by the SPI binding.

In the end even managment of the specific use case for CS0 on
AT91RM9200 has been simplified.

Gregory

Gregory CLEMENT (7):
  spi: atmel: Remove and fix erroneous comments
  spi: atmel: Fix CS high support
  spi: atmel: Configure GPIO per CS instead of by controller
  spi: atmel: Remove useless private field
  spi: atmel: Remove platform data support
  spi: atmel: Improve and fix GPIO CS usage
  spi: atmel: Improve CS0 case support on AT91RM9200

 drivers/spi/Kconfig     |   1 +
 drivers/spi/spi-atmel.c | 154 ++++++++++++++++++++++++----------------
 2 files changed, 92 insertions(+), 63 deletions(-)

-- 
2.23.0


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[PATCH 1/7] spi: atmel: Remove and fix erroneous comments

[Gregory CLEMENT]

Since CSAAT functionality support has been added. Some comments become
wrong. Fix them to match the current driver behavior.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/spi/spi-atmel.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index e34ab587b980..7a17c3e2a8ee 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -312,11 +312,9 @@ static bool atmel_spi_is_v2(struct atmel_spi *as)
  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
  * controllers have CSAAT and friends.
  *
- * Since the CSAAT functionality is a bit weird on newer controllers as
- * well, we use GPIO to control nCSx pins on all controllers, updating
- * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
- * support active-high chipselects despite the controller's belief that
- * only active-low devices/systems exists.
+ * Even controller newer than ar91rm9200, using GPIOs can make sens as
+ * it lets us support active-high chipselects despite the controller's
+ * belief that only active-low devices/systems exists.
  *
  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
  * right when driven with GPIO.  ("Mode Fault does not allow more than one
@@ -1193,8 +1191,6 @@ static int atmel_spi_setup(struct spi_device *spi)
 	if (!as->use_cs_gpios)
 		csr |= SPI_BIT(CSAAT);
 
-	/* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
-	 */
 	csr |= SPI_BF(DLYBS, 0);
 
 	word_delay_csr = atmel_word_delay_csr(spi, as);
-- 
2.23.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Applied "spi: atmel: Remove and fix erroneous comments" to the spi tree

[Mark Brown]

The patch

   spi: atmel: Remove and fix erroneous comments

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

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

From 4d8672d17450b457c0dbbcfe9868438036b4647c Mon Sep 17 00:00:00 2001
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Thu, 17 Oct 2019 16:18:40 +0200
Subject: [PATCH] spi: atmel: Remove and fix erroneous comments

Since CSAAT functionality support has been added. Some comments become
wrong. Fix them to match the current driver behavior.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191017141846.7523-2-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-atmel.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index e34ab587b980..7a17c3e2a8ee 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -312,11 +312,9 @@ static bool atmel_spi_is_v2(struct atmel_spi *as)
  * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
  * controllers have CSAAT and friends.
  *
- * Since the CSAAT functionality is a bit weird on newer controllers as
- * well, we use GPIO to control nCSx pins on all controllers, updating
- * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
- * support active-high chipselects despite the controller's belief that
- * only active-low devices/systems exists.
+ * Even controller newer than ar91rm9200, using GPIOs can make sens as
+ * it lets us support active-high chipselects despite the controller's
+ * belief that only active-low devices/systems exists.
  *
  * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
  * right when driven with GPIO.  ("Mode Fault does not allow more than one
@@ -1193,8 +1191,6 @@ static int atmel_spi_setup(struct spi_device *spi)
 	if (!as->use_cs_gpios)
 		csr |= SPI_BIT(CSAAT);
 
-	/* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
-	 */
 	csr |= SPI_BF(DLYBS, 0);
 
 	word_delay_csr = atmel_word_delay_csr(spi, as);
-- 
2.20.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 2/7] spi: atmel: Fix CS high support

[Gregory CLEMENT]

Until a few years ago, this driver was only used with CS GPIO. The
only exception is CS0 on AT91RM9200 which has to use internal CS. A
limitation of the internal CS is that they don't support CS High.

So by using the CS GPIO the CS high configuration was available except
for the particular case CS0 on RM9200.

When the support for the internal chip-select was added, the check of
the CS high support was not updated. Due to this the driver accepts
this configuration for all the SPI controller v2 (used by all SoCs
excepting the AT91RM9200) whereas the hardware doesn't support it for
infernal CS.

This patch fixes the test to match the hardware capabilities.

Fixes: 4820303480a1 ("spi: atmel: add support for the internal chip-select of the spi controller")
Cc: <stable@vger.kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/spi/spi-atmel.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 7a17c3e2a8ee..6e08ae539bc0 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1176,10 +1176,8 @@ static int atmel_spi_setup(struct spi_device *spi)
 	as = spi_master_get_devdata(spi->master);
 
 	/* see notes above re chipselect */
-	if (!atmel_spi_is_v2(as)
-			&& spi->chip_select == 0
-			&& (spi->mode & SPI_CS_HIGH)) {
-		dev_dbg(&spi->dev, "setup: can't be active-high\n");
+	if (!as->use_cs_gpios && (spi->mode & SPI_CS_HIGH)) {
+		dev_warn(&spi->dev, "setup: non GPIO CS can't be active-high\n");
 		return -EINVAL;
 	}
 
-- 
2.23.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Applied "spi: atmel: Fix CS high support" to the spi tree

[Mark Brown]

The patch

   spi: atmel: Fix CS high support

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

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

From 7cbb16b2122c09f2ae393a1542fed628505b9da6 Mon Sep 17 00:00:00 2001
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Thu, 17 Oct 2019 16:18:41 +0200
Subject: [PATCH] spi: atmel: Fix CS high support

Until a few years ago, this driver was only used with CS GPIO. The
only exception is CS0 on AT91RM9200 which has to use internal CS. A
limitation of the internal CS is that they don't support CS High.

So by using the CS GPIO the CS high configuration was available except
for the particular case CS0 on RM9200.

When the support for the internal chip-select was added, the check of
the CS high support was not updated. Due to this the driver accepts
this configuration for all the SPI controller v2 (used by all SoCs
excepting the AT91RM9200) whereas the hardware doesn't support it for
infernal CS.

This patch fixes the test to match the hardware capabilities.

Fixes: 4820303480a1 ("spi: atmel: add support for the internal chip-select of the spi controller")
Cc: <stable@vger.kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191017141846.7523-3-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-atmel.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 7a17c3e2a8ee..6e08ae539bc0 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1176,10 +1176,8 @@ static int atmel_spi_setup(struct spi_device *spi)
 	as = spi_master_get_devdata(spi->master);
 
 	/* see notes above re chipselect */
-	if (!atmel_spi_is_v2(as)
-			&& spi->chip_select == 0
-			&& (spi->mode & SPI_CS_HIGH)) {
-		dev_dbg(&spi->dev, "setup: can't be active-high\n");
+	if (!as->use_cs_gpios && (spi->mode & SPI_CS_HIGH)) {
+		dev_warn(&spi->dev, "setup: non GPIO CS can't be active-high\n");
 		return -EINVAL;
 	}
 
-- 
2.20.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 3/7] spi: atmel: Configure GPIO per CS instead of by controller

[Gregory CLEMENT]

Instead of setting up the GPIO configuration for the whole controller,
do it at CS level. It will allow to mix internal CS and GPIO CS, which
is not possible with the current implementation.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/spi/spi-atmel.c | 32 ++++++++------------------------
 1 file changed, 8 insertions(+), 24 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 6e08ae539bc0..b511df6a4846 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -275,7 +275,6 @@ struct atmel_spi {
 
 	bool			use_dma;
 	bool			use_pdc;
-	bool			use_cs_gpios;
 
 	bool			keep_cs;
 	bool			cs_active;
@@ -348,7 +347,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 		}
 
 		mr = spi_readl(as, MR);
-		if (as->use_cs_gpios)
+		if (asd->npcs_pin)
 			gpiod_set_value(asd->npcs_pin, 1);
 	} else {
 		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
@@ -365,7 +364,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 		mr = spi_readl(as, MR);
 		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
-		if (as->use_cs_gpios && spi->chip_select != 0)
+		if (asd->npcs_pin && spi->chip_select != 0)
 			gpiod_set_value(asd->npcs_pin, 1);
 		spi_writel(as, MR, mr);
 	}
@@ -389,7 +388,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 
 	dev_dbg(&spi->dev, "DEactivate NPCS, mr %08x\n", mr);
 
-	if (!as->use_cs_gpios)
+	if (!asd->npcs_pin)
 		spi_writel(as, CR, SPI_BIT(LASTXFER));
 	else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
 		gpiod_set_value(asd->npcs_pin, 0);
@@ -1176,7 +1175,7 @@ static int atmel_spi_setup(struct spi_device *spi)
 	as = spi_master_get_devdata(spi->master);
 
 	/* see notes above re chipselect */
-	if (!as->use_cs_gpios && (spi->mode & SPI_CS_HIGH)) {
+	if (!spi->cs_gpiod && (spi->mode & SPI_CS_HIGH)) {
 		dev_warn(&spi->dev, "setup: non GPIO CS can't be active-high\n");
 		return -EINVAL;
 	}
@@ -1186,9 +1185,9 @@ static int atmel_spi_setup(struct spi_device *spi)
 		csr |= SPI_BIT(CPOL);
 	if (!(spi->mode & SPI_CPHA))
 		csr |= SPI_BIT(NCPHA);
-	if (!as->use_cs_gpios)
-		csr |= SPI_BIT(CSAAT);
 
+	if (!spi->cs_gpiod)
+		csr |= SPI_BIT(CSAAT);
 	csr |= SPI_BF(DLYBS, 0);
 
 	word_delay_csr = atmel_word_delay_csr(spi, as);
@@ -1206,20 +1205,8 @@ static int atmel_spi_setup(struct spi_device *spi)
 		if (!asd)
 			return -ENOMEM;
 
-		/*
-		 * If use_cs_gpios is true this means that we have "cs-gpios"
-		 * defined in the device tree node so we should have
-		 * gotten the GPIO lines from the device tree inside the
-		 * SPI core. Warn if this is not the case but continue since
-		 * CS GPIOs are after all optional.
-		 */
-		if (as->use_cs_gpios) {
-			if (!spi->cs_gpiod) {
-				dev_err(&spi->dev,
-					"host claims to use CS GPIOs but no CS found in DT by the SPI core\n");
-			}
+		if (spi->cs_gpiod)
 			asd->npcs_pin = spi->cs_gpiod;
-		}
 
 		spi->controller_state = asd;
 	}
@@ -1551,13 +1538,10 @@ static int atmel_spi_probe(struct platform_device *pdev)
 	 * discovered by the SPI core when registering the SPI master
 	 * and assigned to each SPI device.
 	 */
-	as->use_cs_gpios = true;
 	if (atmel_spi_is_v2(as) &&
 	    pdev->dev.of_node &&
-	    !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
-		as->use_cs_gpios = false;
+	    !of_get_property(pdev->dev.of_node, "cs-gpios", NULL))
 		master->num_chipselect = 4;
-	}
 
 	as->use_dma = false;
 	as->use_pdc = false;
-- 
2.23.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Applied "spi: atmel: Configure GPIO per CS instead of by controller" to the spi tree

[Mark Brown]

The patch

   spi: atmel: Configure GPIO per CS instead of by controller

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

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

From 585d18f7ebd1dba7400dcc7189a5f7223b821374 Mon Sep 17 00:00:00 2001
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Thu, 17 Oct 2019 16:18:42 +0200
Subject: [PATCH] spi: atmel: Configure GPIO per CS instead of by controller

Instead of setting up the GPIO configuration for the whole controller,
do it at CS level. It will allow to mix internal CS and GPIO CS, which
is not possible with the current implementation.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191017141846.7523-4-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-atmel.c | 32 ++++++++------------------------
 1 file changed, 8 insertions(+), 24 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 6e08ae539bc0..b511df6a4846 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -275,7 +275,6 @@ struct atmel_spi {
 
 	bool			use_dma;
 	bool			use_pdc;
-	bool			use_cs_gpios;
 
 	bool			keep_cs;
 	bool			cs_active;
@@ -348,7 +347,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 		}
 
 		mr = spi_readl(as, MR);
-		if (as->use_cs_gpios)
+		if (asd->npcs_pin)
 			gpiod_set_value(asd->npcs_pin, 1);
 	} else {
 		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
@@ -365,7 +364,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 		mr = spi_readl(as, MR);
 		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
-		if (as->use_cs_gpios && spi->chip_select != 0)
+		if (asd->npcs_pin && spi->chip_select != 0)
 			gpiod_set_value(asd->npcs_pin, 1);
 		spi_writel(as, MR, mr);
 	}
@@ -389,7 +388,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 
 	dev_dbg(&spi->dev, "DEactivate NPCS, mr %08x\n", mr);
 
-	if (!as->use_cs_gpios)
+	if (!asd->npcs_pin)
 		spi_writel(as, CR, SPI_BIT(LASTXFER));
 	else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
 		gpiod_set_value(asd->npcs_pin, 0);
@@ -1176,7 +1175,7 @@ static int atmel_spi_setup(struct spi_device *spi)
 	as = spi_master_get_devdata(spi->master);
 
 	/* see notes above re chipselect */
-	if (!as->use_cs_gpios && (spi->mode & SPI_CS_HIGH)) {
+	if (!spi->cs_gpiod && (spi->mode & SPI_CS_HIGH)) {
 		dev_warn(&spi->dev, "setup: non GPIO CS can't be active-high\n");
 		return -EINVAL;
 	}
@@ -1186,9 +1185,9 @@ static int atmel_spi_setup(struct spi_device *spi)
 		csr |= SPI_BIT(CPOL);
 	if (!(spi->mode & SPI_CPHA))
 		csr |= SPI_BIT(NCPHA);
-	if (!as->use_cs_gpios)
-		csr |= SPI_BIT(CSAAT);
 
+	if (!spi->cs_gpiod)
+		csr |= SPI_BIT(CSAAT);
 	csr |= SPI_BF(DLYBS, 0);
 
 	word_delay_csr = atmel_word_delay_csr(spi, as);
@@ -1206,20 +1205,8 @@ static int atmel_spi_setup(struct spi_device *spi)
 		if (!asd)
 			return -ENOMEM;
 
-		/*
-		 * If use_cs_gpios is true this means that we have "cs-gpios"
-		 * defined in the device tree node so we should have
-		 * gotten the GPIO lines from the device tree inside the
-		 * SPI core. Warn if this is not the case but continue since
-		 * CS GPIOs are after all optional.
-		 */
-		if (as->use_cs_gpios) {
-			if (!spi->cs_gpiod) {
-				dev_err(&spi->dev,
-					"host claims to use CS GPIOs but no CS found in DT by the SPI core\n");
-			}
+		if (spi->cs_gpiod)
 			asd->npcs_pin = spi->cs_gpiod;
-		}
 
 		spi->controller_state = asd;
 	}
@@ -1551,13 +1538,10 @@ static int atmel_spi_probe(struct platform_device *pdev)
 	 * discovered by the SPI core when registering the SPI master
 	 * and assigned to each SPI device.
 	 */
-	as->use_cs_gpios = true;
 	if (atmel_spi_is_v2(as) &&
 	    pdev->dev.of_node &&
-	    !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
-		as->use_cs_gpios = false;
+	    !of_get_property(pdev->dev.of_node, "cs-gpios", NULL))
 		master->num_chipselect = 4;
-	}
 
 	as->use_dma = false;
 	as->use_pdc = false;
-- 
2.20.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 4/7] spi: atmel: Remove useless private field

[Gregory CLEMENT]

Since the conversion to GPIO descriptor, the GPIO used as chip select,
can be directly access from the spi_device struct. So there is no need
to keep the field npcs_pin.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/spi/spi-atmel.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index b511df6a4846..19600de40422 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -284,7 +284,6 @@ struct atmel_spi {
 
 /* Controller-specific per-slave state */
 struct atmel_spi_device {
-	struct gpio_desc	*npcs_pin;
 	u32			csr;
 };
 
@@ -347,8 +346,8 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 		}
 
 		mr = spi_readl(as, MR);
-		if (asd->npcs_pin)
-			gpiod_set_value(asd->npcs_pin, 1);
+		if (spi->cs_gpiod)
+			gpiod_set_value(spi->cs_gpiod, 1);
 	} else {
 		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
 		int i;
@@ -364,8 +363,8 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 		mr = spi_readl(as, MR);
 		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
-		if (asd->npcs_pin && spi->chip_select != 0)
-			gpiod_set_value(asd->npcs_pin, 1);
+		if (spi->cs_gpiod && spi->chip_select != 0)
+			gpiod_set_value(spi->cs_gpiod, 1);
 		spi_writel(as, MR, mr);
 	}
 
@@ -374,7 +373,6 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 {
-	struct atmel_spi_device *asd = spi->controller_state;
 	u32 mr;
 
 	/* only deactivate *this* device; sometimes transfers to
@@ -388,10 +386,10 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 
 	dev_dbg(&spi->dev, "DEactivate NPCS, mr %08x\n", mr);
 
-	if (!asd->npcs_pin)
+	if (!spi->cs_gpiod)
 		spi_writel(as, CR, SPI_BIT(LASTXFER));
 	else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
-		gpiod_set_value(asd->npcs_pin, 0);
+		gpiod_set_value(spi->cs_gpiod, 0);
 }
 
 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
@@ -1205,9 +1203,6 @@ static int atmel_spi_setup(struct spi_device *spi)
 		if (!asd)
 			return -ENOMEM;
 
-		if (spi->cs_gpiod)
-			asd->npcs_pin = spi->cs_gpiod;
-
 		spi->controller_state = asd;
 	}
 
-- 
2.23.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Applied "spi: atmel: Remove useless private field" to the spi tree

[Mark Brown]

The patch

   spi: atmel: Remove useless private field

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

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

From 60086e23e64f7b3b60d957471cfd10948e25648e Mon Sep 17 00:00:00 2001
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Thu, 17 Oct 2019 16:18:43 +0200
Subject: [PATCH] spi: atmel: Remove useless private field

Since the conversion to GPIO descriptor, the GPIO used as chip select,
can be directly access from the spi_device struct. So there is no need
to keep the field npcs_pin.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191017141846.7523-5-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-atmel.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index b511df6a4846..19600de40422 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -284,7 +284,6 @@ struct atmel_spi {
 
 /* Controller-specific per-slave state */
 struct atmel_spi_device {
-	struct gpio_desc	*npcs_pin;
 	u32			csr;
 };
 
@@ -347,8 +346,8 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 		}
 
 		mr = spi_readl(as, MR);
-		if (asd->npcs_pin)
-			gpiod_set_value(asd->npcs_pin, 1);
+		if (spi->cs_gpiod)
+			gpiod_set_value(spi->cs_gpiod, 1);
 	} else {
 		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
 		int i;
@@ -364,8 +363,8 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 		mr = spi_readl(as, MR);
 		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
-		if (asd->npcs_pin && spi->chip_select != 0)
-			gpiod_set_value(asd->npcs_pin, 1);
+		if (spi->cs_gpiod && spi->chip_select != 0)
+			gpiod_set_value(spi->cs_gpiod, 1);
 		spi_writel(as, MR, mr);
 	}
 
@@ -374,7 +373,6 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 {
-	struct atmel_spi_device *asd = spi->controller_state;
 	u32 mr;
 
 	/* only deactivate *this* device; sometimes transfers to
@@ -388,10 +386,10 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 
 	dev_dbg(&spi->dev, "DEactivate NPCS, mr %08x\n", mr);
 
-	if (!asd->npcs_pin)
+	if (!spi->cs_gpiod)
 		spi_writel(as, CR, SPI_BIT(LASTXFER));
 	else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
-		gpiod_set_value(asd->npcs_pin, 0);
+		gpiod_set_value(spi->cs_gpiod, 0);
 }
 
 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
@@ -1205,9 +1203,6 @@ static int atmel_spi_setup(struct spi_device *spi)
 		if (!asd)
 			return -ENOMEM;
 
-		if (spi->cs_gpiod)
-			asd->npcs_pin = spi->cs_gpiod;
-
 		spi->controller_state = asd;
 	}
 
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 5/7] spi: atmel: Remove platform data support

[Gregory CLEMENT]

This driver is now only used through the device tree. Simplify code
by explicitly depend on device tree.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/spi/Kconfig     |  1 +
 drivers/spi/spi-atmel.c | 16 ++--------------
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 6f7fdcbb9151..6c0c1f55bd71 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -80,6 +80,7 @@ config SPI_ARMADA_3700
 config SPI_ATMEL
 	tristate "Atmel SPI Controller"
 	depends on ARCH_AT91 || COMPILE_TEST
+	depends on OF
 	help
 	  This selects a driver for the Atmel SPI Controller, present on
 	  many AT91 ARM chips.
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 19600de40422..1ff5b20eabf7 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1500,7 +1500,7 @@ static int atmel_spi_probe(struct platform_device *pdev)
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
 	master->dev.of_node = pdev->dev.of_node;
 	master->bus_num = pdev->id;
-	master->num_chipselect = master->dev.of_node ? 0 : 4;
+	master->num_chipselect = 4;
 	master->setup = atmel_spi_setup;
 	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
 	master->transfer_one_message = atmel_spi_transfer_one_message;
@@ -1528,16 +1528,6 @@ static int atmel_spi_probe(struct platform_device *pdev)
 
 	atmel_get_caps(as);
 
-	/*
-	 * If there are chip selects in the device tree, those will be
-	 * discovered by the SPI core when registering the SPI master
-	 * and assigned to each SPI device.
-	 */
-	if (atmel_spi_is_v2(as) &&
-	    pdev->dev.of_node &&
-	    !of_get_property(pdev->dev.of_node, "cs-gpios", NULL))
-		master->num_chipselect = 4;
-
 	as->use_dma = false;
 	as->use_pdc = false;
 	if (as->caps.has_dma_support) {
@@ -1745,20 +1735,18 @@ static const struct dev_pm_ops atmel_spi_pm_ops = {
 #define ATMEL_SPI_PM_OPS	NULL
 #endif
 
-#if defined(CONFIG_OF)
 static const struct of_device_id atmel_spi_dt_ids[] = {
 	{ .compatible = "atmel,at91rm9200-spi" },
 	{ /* sentinel */ }
 };
 
 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
-#endif
 
 static struct platform_driver atmel_spi_driver = {
 	.driver		= {
 		.name	= "atmel_spi",
 		.pm	= ATMEL_SPI_PM_OPS,
-		.of_match_table	= of_match_ptr(atmel_spi_dt_ids),
+		.of_match_table	= atmel_spi_dt_ids,
 	},
 	.probe		= atmel_spi_probe,
 	.remove		= atmel_spi_remove,
-- 
2.23.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Applied "spi: atmel: Remove platform data support" to the spi tree

[Mark Brown]

The patch

   spi: atmel: Remove platform data support

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

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

From 1cb84b02bf130f34ee81f99bc7dee5bca2943ed7 Mon Sep 17 00:00:00 2001
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Thu, 17 Oct 2019 16:18:44 +0200
Subject: [PATCH] spi: atmel: Remove platform data support

This driver is now only used through the device tree. Simplify code
by explicitly depend on device tree.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191017141846.7523-6-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/Kconfig     |  1 +
 drivers/spi/spi-atmel.c | 16 ++--------------
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 6f7fdcbb9151..6c0c1f55bd71 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -80,6 +80,7 @@ config SPI_ARMADA_3700
 config SPI_ATMEL
 	tristate "Atmel SPI Controller"
 	depends on ARCH_AT91 || COMPILE_TEST
+	depends on OF
 	help
 	  This selects a driver for the Atmel SPI Controller, present on
 	  many AT91 ARM chips.
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 19600de40422..1ff5b20eabf7 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1500,7 +1500,7 @@ static int atmel_spi_probe(struct platform_device *pdev)
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
 	master->dev.of_node = pdev->dev.of_node;
 	master->bus_num = pdev->id;
-	master->num_chipselect = master->dev.of_node ? 0 : 4;
+	master->num_chipselect = 4;
 	master->setup = atmel_spi_setup;
 	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
 	master->transfer_one_message = atmel_spi_transfer_one_message;
@@ -1528,16 +1528,6 @@ static int atmel_spi_probe(struct platform_device *pdev)
 
 	atmel_get_caps(as);
 
-	/*
-	 * If there are chip selects in the device tree, those will be
-	 * discovered by the SPI core when registering the SPI master
-	 * and assigned to each SPI device.
-	 */
-	if (atmel_spi_is_v2(as) &&
-	    pdev->dev.of_node &&
-	    !of_get_property(pdev->dev.of_node, "cs-gpios", NULL))
-		master->num_chipselect = 4;
-
 	as->use_dma = false;
 	as->use_pdc = false;
 	if (as->caps.has_dma_support) {
@@ -1745,20 +1735,18 @@ static const struct dev_pm_ops atmel_spi_pm_ops = {
 #define ATMEL_SPI_PM_OPS	NULL
 #endif
 
-#if defined(CONFIG_OF)
 static const struct of_device_id atmel_spi_dt_ids[] = {
 	{ .compatible = "atmel,at91rm9200-spi" },
 	{ /* sentinel */ }
 };
 
 MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
-#endif
 
 static struct platform_driver atmel_spi_driver = {
 	.driver		= {
 		.name	= "atmel_spi",
 		.pm	= ATMEL_SPI_PM_OPS,
-		.of_match_table	= of_match_ptr(atmel_spi_dt_ids),
+		.of_match_table	= atmel_spi_dt_ids,
 	},
 	.probe		= atmel_spi_probe,
 	.remove		= atmel_spi_remove,
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 6/7] spi: atmel: Improve and fix GPIO CS usage

[Gregory CLEMENT]

In the previous implementation of this driver, the index of the GPIO
used as CS was linked to the offset of the CS register used to
configure the transfer.

With this new implementation the first CS register not used by
internal CS is associated to all the GPIO CS. It allows to not be
anymore limited to have only 4 CS managed, now it is possible to have
in the same time until 3 internal CS and no more limit for the CS
GPIO.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/spi/spi-atmel.c | 74 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 66 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 1ff5b20eabf7..ac5e2ddf9e1b 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -280,6 +280,8 @@ struct atmel_spi {
 	bool			cs_active;
 
 	u32			fifo_size;
+	u8			native_cs_free;
+	u8			native_cs_for_gpio;
 };
 
 /* Controller-specific per-slave state */
@@ -324,23 +326,29 @@ static bool atmel_spi_is_v2(struct atmel_spi *as)
 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 {
 	struct atmel_spi_device *asd = spi->controller_state;
+	int chip_select;
 	u32 mr;
 
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
+
 	if (atmel_spi_is_v2(as)) {
-		spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
+		spi_writel(as, CSR0 + 4 * chip_select, asd->csr);
 		/* For the low SPI version, there is a issue that PDC transfer
 		 * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
 		 */
 		spi_writel(as, CSR0, asd->csr);
 		if (as->caps.has_wdrbt) {
 			spi_writel(as, MR,
-					SPI_BF(PCS, ~(0x01 << spi->chip_select))
+					SPI_BF(PCS, ~(0x01 << chip_select))
 					| SPI_BIT(WDRBT)
 					| SPI_BIT(MODFDIS)
 					| SPI_BIT(MSTR));
 		} else {
 			spi_writel(as, MR,
-					SPI_BF(PCS, ~(0x01 << spi->chip_select))
+					SPI_BF(PCS, ~(0x01 << chip_select))
 					| SPI_BIT(MODFDIS)
 					| SPI_BIT(MSTR));
 		}
@@ -362,7 +370,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 		}
 
 		mr = spi_readl(as, MR);
-		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
+		mr = SPI_BFINS(PCS, ~(1 << chip_select), mr);
 		if (spi->cs_gpiod && spi->chip_select != 0)
 			gpiod_set_value(spi->cs_gpiod, 1);
 		spi_writel(as, MR, mr);
@@ -373,13 +381,19 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 {
+	int chip_select;
 	u32 mr;
 
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
+
 	/* only deactivate *this* device; sometimes transfers to
 	 * another device may be active when this routine is called.
 	 */
 	mr = spi_readl(as, MR);
-	if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
+	if (~SPI_BFEXT(PCS, mr) & (1 << chip_select)) {
 		mr = SPI_BFINS(PCS, 0xf, mr);
 		spi_writel(as, MR, mr);
 	}
@@ -815,6 +829,12 @@ static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 {
 	u32			scbr, csr;
 	unsigned long		bus_hz;
+	int chip_select;
+
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
 
 	/* v1 chips start out at half the peripheral bus speed. */
 	bus_hz = as->spi_clk;
@@ -843,9 +863,9 @@ static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 			xfer->speed_hz, scbr, bus_hz);
 		return -EINVAL;
 	}
-	csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
+	csr = spi_readl(as, CSR0 + 4 * chip_select);
 	csr = SPI_BFINS(SCBR, scbr, csr);
-	spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+	spi_writel(as, CSR0 + 4 * chip_select, csr);
 
 	return 0;
 }
@@ -1162,12 +1182,32 @@ static int atmel_word_delay_csr(struct spi_device *spi, struct atmel_spi *as)
 	return (as->spi_clk / 1000000 * value) >> 5;
 }
 
+static void initialize_native_cs_for_gpio(struct atmel_spi *as)
+{
+	int i;
+	struct spi_master *master = platform_get_drvdata(as->pdev);
+
+	if (!as->native_cs_free)
+		return; /* already initialized */
+
+	if (!master->cs_gpiods)
+		return; /* No CS GPIO */
+
+	for (i = 0; i < 4; i++)
+		if (master->cs_gpiods[i])
+			as->native_cs_free |= BIT(i);
+
+	if (as->native_cs_free)
+		as->native_cs_for_gpio = ffs(as->native_cs_free);
+}
+
 static int atmel_spi_setup(struct spi_device *spi)
 {
 	struct atmel_spi	*as;
 	struct atmel_spi_device	*asd;
 	u32			csr;
 	unsigned int		bits = spi->bits_per_word;
+	int chip_select;
 	int			word_delay_csr;
 
 	as = spi_master_get_devdata(spi->master);
@@ -1178,6 +1218,24 @@ static int atmel_spi_setup(struct spi_device *spi)
 		return -EINVAL;
 	}
 
+	/* Setup() is called during spi_register_controller(aka
+	 * spi_register_master) but after all membmers of the cs_gpiod
+	 * array have been filled, so we can looked for which native
+	 * CS will be free for using with GPIO
+	 */
+	initialize_native_cs_for_gpio(as);
+
+	if (spi->cs_gpiod && as->native_cs_free) {
+		dev_err(&spi->dev,
+			"No native CS available to support this GPIO CS\n");
+		return -EBUSY;
+	}
+
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
+
 	csr = SPI_BF(BITS, bits - 8);
 	if (spi->mode & SPI_CPOL)
 		csr |= SPI_BIT(CPOL);
@@ -1213,7 +1271,7 @@ static int atmel_spi_setup(struct spi_device *spi)
 		bits, spi->mode, spi->chip_select, csr);
 
 	if (!atmel_spi_is_v2(as))
-		spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+		spi_writel(as, CSR0 + 4 * chip_select, csr);
 
 	return 0;
 }
-- 
2.23.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Applied "spi: atmel: Improve and fix GPIO CS usage" to the spi tree

[Mark Brown]

The patch

   spi: atmel: Improve and fix GPIO CS usage

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

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

From 57e3137710443a3227a54c425b9c606425678c8f Mon Sep 17 00:00:00 2001
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Thu, 17 Oct 2019 16:18:45 +0200
Subject: [PATCH] spi: atmel: Improve and fix GPIO CS usage

In the previous implementation of this driver, the index of the GPIO
used as CS was linked to the offset of the CS register used to
configure the transfer.

With this new implementation the first CS register not used by
internal CS is associated to all the GPIO CS. It allows to not be
anymore limited to have only 4 CS managed, now it is possible to have
in the same time until 3 internal CS and no more limit for the CS
GPIO.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191017141846.7523-7-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-atmel.c | 74 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 66 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 1ff5b20eabf7..ac5e2ddf9e1b 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -280,6 +280,8 @@ struct atmel_spi {
 	bool			cs_active;
 
 	u32			fifo_size;
+	u8			native_cs_free;
+	u8			native_cs_for_gpio;
 };
 
 /* Controller-specific per-slave state */
@@ -324,23 +326,29 @@ static bool atmel_spi_is_v2(struct atmel_spi *as)
 static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 {
 	struct atmel_spi_device *asd = spi->controller_state;
+	int chip_select;
 	u32 mr;
 
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
+
 	if (atmel_spi_is_v2(as)) {
-		spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
+		spi_writel(as, CSR0 + 4 * chip_select, asd->csr);
 		/* For the low SPI version, there is a issue that PDC transfer
 		 * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
 		 */
 		spi_writel(as, CSR0, asd->csr);
 		if (as->caps.has_wdrbt) {
 			spi_writel(as, MR,
-					SPI_BF(PCS, ~(0x01 << spi->chip_select))
+					SPI_BF(PCS, ~(0x01 << chip_select))
 					| SPI_BIT(WDRBT)
 					| SPI_BIT(MODFDIS)
 					| SPI_BIT(MSTR));
 		} else {
 			spi_writel(as, MR,
-					SPI_BF(PCS, ~(0x01 << spi->chip_select))
+					SPI_BF(PCS, ~(0x01 << chip_select))
 					| SPI_BIT(MODFDIS)
 					| SPI_BIT(MSTR));
 		}
@@ -362,7 +370,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 		}
 
 		mr = spi_readl(as, MR);
-		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
+		mr = SPI_BFINS(PCS, ~(1 << chip_select), mr);
 		if (spi->cs_gpiod && spi->chip_select != 0)
 			gpiod_set_value(spi->cs_gpiod, 1);
 		spi_writel(as, MR, mr);
@@ -373,13 +381,19 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 {
+	int chip_select;
 	u32 mr;
 
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
+
 	/* only deactivate *this* device; sometimes transfers to
 	 * another device may be active when this routine is called.
 	 */
 	mr = spi_readl(as, MR);
-	if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
+	if (~SPI_BFEXT(PCS, mr) & (1 << chip_select)) {
 		mr = SPI_BFINS(PCS, 0xf, mr);
 		spi_writel(as, MR, mr);
 	}
@@ -815,6 +829,12 @@ static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 {
 	u32			scbr, csr;
 	unsigned long		bus_hz;
+	int chip_select;
+
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
 
 	/* v1 chips start out at half the peripheral bus speed. */
 	bus_hz = as->spi_clk;
@@ -843,9 +863,9 @@ static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
 			xfer->speed_hz, scbr, bus_hz);
 		return -EINVAL;
 	}
-	csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
+	csr = spi_readl(as, CSR0 + 4 * chip_select);
 	csr = SPI_BFINS(SCBR, scbr, csr);
-	spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+	spi_writel(as, CSR0 + 4 * chip_select, csr);
 
 	return 0;
 }
@@ -1162,12 +1182,32 @@ static int atmel_word_delay_csr(struct spi_device *spi, struct atmel_spi *as)
 	return (as->spi_clk / 1000000 * value) >> 5;
 }
 
+static void initialize_native_cs_for_gpio(struct atmel_spi *as)
+{
+	int i;
+	struct spi_master *master = platform_get_drvdata(as->pdev);
+
+	if (!as->native_cs_free)
+		return; /* already initialized */
+
+	if (!master->cs_gpiods)
+		return; /* No CS GPIO */
+
+	for (i = 0; i < 4; i++)
+		if (master->cs_gpiods[i])
+			as->native_cs_free |= BIT(i);
+
+	if (as->native_cs_free)
+		as->native_cs_for_gpio = ffs(as->native_cs_free);
+}
+
 static int atmel_spi_setup(struct spi_device *spi)
 {
 	struct atmel_spi	*as;
 	struct atmel_spi_device	*asd;
 	u32			csr;
 	unsigned int		bits = spi->bits_per_word;
+	int chip_select;
 	int			word_delay_csr;
 
 	as = spi_master_get_devdata(spi->master);
@@ -1178,6 +1218,24 @@ static int atmel_spi_setup(struct spi_device *spi)
 		return -EINVAL;
 	}
 
+	/* Setup() is called during spi_register_controller(aka
+	 * spi_register_master) but after all membmers of the cs_gpiod
+	 * array have been filled, so we can looked for which native
+	 * CS will be free for using with GPIO
+	 */
+	initialize_native_cs_for_gpio(as);
+
+	if (spi->cs_gpiod && as->native_cs_free) {
+		dev_err(&spi->dev,
+			"No native CS available to support this GPIO CS\n");
+		return -EBUSY;
+	}
+
+	if (spi->cs_gpiod)
+		chip_select = as->native_cs_for_gpio;
+	else
+		chip_select = spi->chip_select;
+
 	csr = SPI_BF(BITS, bits - 8);
 	if (spi->mode & SPI_CPOL)
 		csr |= SPI_BIT(CPOL);
@@ -1213,7 +1271,7 @@ static int atmel_spi_setup(struct spi_device *spi)
 		bits, spi->mode, spi->chip_select, csr);
 
 	if (!atmel_spi_is_v2(as))
-		spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+		spi_writel(as, CSR0 + 4 * chip_select, csr);
 
 	return 0;
 }
-- 
2.20.1


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[PATCH 7/7] spi: atmel: Improve CS0 case support on AT91RM9200

[Gregory CLEMENT]

Thanks to the recent change in this driver, it is now possible to
prevent using the CS0 with GPIO during setup. It then allows to remove
the special handling of this case in the cs_activate() and
cs_deactivate() functions.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/spi/spi-atmel.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index ac5e2ddf9e1b..d88e2aa64839 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -371,7 +371,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 		mr = spi_readl(as, MR);
 		mr = SPI_BFINS(PCS, ~(1 << chip_select), mr);
-		if (spi->cs_gpiod && spi->chip_select != 0)
+		if (spi->cs_gpiod)
 			gpiod_set_value(spi->cs_gpiod, 1);
 		spi_writel(as, MR, mr);
 	}
@@ -402,7 +402,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 
 	if (!spi->cs_gpiod)
 		spi_writel(as, CR, SPI_BIT(LASTXFER));
-	else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
+	else
 		gpiod_set_value(spi->cs_gpiod, 0);
 }
 
@@ -1193,7 +1193,16 @@ static void initialize_native_cs_for_gpio(struct atmel_spi *as)
 	if (!master->cs_gpiods)
 		return; /* No CS GPIO */
 
-	for (i = 0; i < 4; i++)
+	/*
+	 * On the first version of the controller (AT91RM9200), CS0
+	 * can't be used associated with GPIO
+	 */
+	if (atmel_spi_is_v2(as))
+		i = 0;
+	else
+		i = 1;
+
+	for (; i < 4; i++)
 		if (master->cs_gpiods[i])
 			as->native_cs_free |= BIT(i);
 
-- 
2.23.0


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Applied "spi: atmel: Improve CS0 case support on AT91RM9200" to the spi tree

[Mark Brown]

The patch

   spi: atmel: Improve CS0 case support on AT91RM9200

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-5.5

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

From 9c86f12a36479dec06df3e4a4f31cecf8eba0222 Mon Sep 17 00:00:00 2001
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Thu, 17 Oct 2019 16:18:46 +0200
Subject: [PATCH] spi: atmel: Improve CS0 case support on AT91RM9200

Thanks to the recent change in this driver, it is now possible to
prevent using the CS0 with GPIO during setup. It then allows to remove
the special handling of this case in the cs_activate() and
cs_deactivate() functions.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191017141846.7523-8-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-atmel.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index ac5e2ddf9e1b..d88e2aa64839 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -371,7 +371,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 		mr = spi_readl(as, MR);
 		mr = SPI_BFINS(PCS, ~(1 << chip_select), mr);
-		if (spi->cs_gpiod && spi->chip_select != 0)
+		if (spi->cs_gpiod)
 			gpiod_set_value(spi->cs_gpiod, 1);
 		spi_writel(as, MR, mr);
 	}
@@ -402,7 +402,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 
 	if (!spi->cs_gpiod)
 		spi_writel(as, CR, SPI_BIT(LASTXFER));
-	else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
+	else
 		gpiod_set_value(spi->cs_gpiod, 0);
 }
 
@@ -1193,7 +1193,16 @@ static void initialize_native_cs_for_gpio(struct atmel_spi *as)
 	if (!master->cs_gpiods)
 		return; /* No CS GPIO */
 
-	for (i = 0; i < 4; i++)
+	/*
+	 * On the first version of the controller (AT91RM9200), CS0
+	 * can't be used associated with GPIO
+	 */
+	if (atmel_spi_is_v2(as))
+		i = 0;
+	else
+		i = 1;
+
+	for (; i < 4; i++)
 		if (master->cs_gpiods[i])
 			as->native_cs_free |= BIT(i);
 
-- 
2.20.1


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