[PATCH 0/3] i2c: bcm2835: Add bcm2711 support

[PATCH 0/3] i2c: bcm2835: Add bcm2711 support

[Stefan Wahren]

This series has been split out of the recent Raspberry Pi 4 support
series [1]. I hope patch 1 and 2 have a chance to get into Linux 5.4.

Changes since split:
- add Rob's and Eric's Reviewed-by
- address Wolfram's comment regarding of_device_get_match_data
- add patch to distinguish the many interfaces on bcm2711

[1] - https://marc.info/?linux-arm-kernel&m=3D156571347332483

Stefan Wahren (3):
  dt-bindings: i2c: bcm2835: Add brcm,bcm2711 compatible
  i2c: bcm2835: Avoid clk stretch quirk for BCM2711
  i2c: bcm2835: Add full name of devicetree node to adapter name

 Documentation/devicetree/bindings/i2c/brcm,bcm2835-i2c.txt |  4 +++-
 drivers/i2c/busses/i2c-bcm2835.c                           | 11 +++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

--
2.7.4


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[PATCH 1/3] dt-bindings: i2c: bcm2835: Add brcm,bcm2711 compatible

[Stefan Wahren]

Add a new compatible for the BCM2711, which hasn't the clock stretch bug.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/i2c/brcm,bcm2835-i2c.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/i2c/brcm,bcm2835-i2c.txt b/Documentation/devicetree/bindings/i2c/brcm,bcm2835-i2c.txt
index e9de375..c9a6587 100644
--- a/Documentation/devicetree/bindings/i2c/brcm,bcm2835-i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/brcm,bcm2835-i2c.txt
@@ -1,7 +1,9 @@
 Broadcom BCM2835 I2C controller

 Required properties:
-- compatible : Should be "brcm,bcm2835-i2c".
+- compatible : Should be one of:
+	"brcm,bcm2711-i2c"
+	"brcm,bcm2835-i2c"
 - reg: Should contain register location and length.
 - interrupts: Should contain interrupt.
 - clocks : The clock feeding the I2C controller.
--
2.7.4


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[PATCH 2/3] i2c: bcm2835: Avoid clk stretch quirk for BCM2711

[Stefan Wahren]

The I2C block on the BCM2711 isn't affected by the clk stretching bug.
So there is no need to apply the corresponding quirk.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
---
 drivers/i2c/busses/i2c-bcm2835.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index 67752f7..ab5502f 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -12,6 +12,7 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>

@@ -389,7 +390,7 @@ static const struct i2c_algorithm bcm2835_i2c_algo = {
 };

 /*
- * This HW was reported to have problems with clock stretching:
+ * The BCM2835 was reported to have problems with clock stretching:
  * http://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html
  * https://www.raspberrypi.org/forums/viewtopic.php?p=146272
  */
@@ -475,7 +476,7 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
 	adap->algo = &bcm2835_i2c_algo;
 	adap->dev.parent = &pdev->dev;
 	adap->dev.of_node = pdev->dev.of_node;
-	adap->quirks = &bcm2835_i2c_quirks;
+	adap->quirks = of_device_get_match_data(&pdev->dev);

 	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0);

@@ -501,7 +502,8 @@ static int bcm2835_i2c_remove(struct platform_device *pdev)
 }

 static const struct of_device_id bcm2835_i2c_of_match[] = {
-	{ .compatible = "brcm,bcm2835-i2c" },
+	{ .compatible = "brcm,bcm2711-i2c" },
+	{ .compatible = "brcm,bcm2835-i2c", .data = &bcm2835_i2c_quirks },
 	{},
 };
 MODULE_DEVICE_TABLE(of, bcm2835_i2c_of_match);
--
2.7.4


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[PATCH 3/3] i2c: bcm2835: Add full name of devicetree node to adapter name

[Stefan Wahren]

Inspired by Lori Hikichi's patch for iproc, this adds the full name of
the devicetree node to the adapter name. With the introduction of
BCM2711 it's very difficult to distinguish between the multiple instances.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
---
 drivers/i2c/busses/i2c-bcm2835.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index ab5502f..e01b2b5 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -472,7 +472,8 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
 	i2c_set_adapdata(adap, i2c_dev);
 	adap->owner = THIS_MODULE;
 	adap->class = I2C_CLASS_DEPRECATED;
-	strlcpy(adap->name, "bcm2835 I2C adapter", sizeof(adap->name));
+	snprintf(adap->name, sizeof(adap->name), "bcm2835 (%s)",
+		 of_node_full_name(pdev->dev.of_node));
 	adap->algo = &bcm2835_i2c_algo;
 	adap->dev.parent = &pdev->dev;
 	adap->dev.of_node = pdev->dev.of_node;
--
2.7.4


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Re: [PATCH 3/3] i2c: bcm2835: Add full name of devicetree node to adapter name

[Scott Branden]

On 2019-08-27 10:04 a.m., Stefan Wahren wrote:
> Inspired by Lori Hikichi's patch for iproc, this adds the full name of
> the devicetree node to the adapter name. With the introduction of
> BCM2711 it's very difficult to distinguish between the multiple instances.
>
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Scott Branden <scott.branden@broadcom.com>
> =2D--
>   drivers/i2c/busses/i2c-bcm2835.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm=
> 2835.c
> index ab5502f..e01b2b5 100644
> =2D-- a/drivers/i2c/busses/i2c-bcm2835.c
> +++ b/drivers/i2c/busses/i2c-bcm2835.c
> @@ -472,7 +472,8 @@ static int bcm2835_i2c_probe(struct platform_device *p=
> dev)
>   	i2c_set_adapdata(adap, i2c_dev);
>   	adap->owner =3D THIS_MODULE;
>   	adap->class =3D I2C_CLASS_DEPRECATED;
> -	strlcpy(adap->name, "bcm2835 I2C adapter", sizeof(adap->name));
> +	snprintf(adap->name, sizeof(adap->name), "bcm2835 (%s)",
> +		 of_node_full_name(pdev->dev.of_node));
>   	adap->algo =3D &bcm2835_i2c_algo;
>   	adap->dev.parent =3D &pdev->dev;
>   	adap->dev.of_node =3D pdev->dev.of_node;
> =2D-
> 2.7.4
>


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Re: [PATCH 1/3] dt-bindings: i2c: bcm2835: Add brcm,bcm2711 compatible

[Wolfram Sang]

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On Tue, Aug 27, 2019 at 07:04:14PM +0200, Stefan Wahren wrote:
> Add a new compatible for the BCM2711, which hasn't the clock stretch bug.
> 
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> Reviewed-by: Eric Anholt <eric@anholt.net>
> Reviewed-by: Rob Herring <robh@kernel.org>

Applied to for-next, thanks!


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Re: [PATCH 2/3] i2c: bcm2835: Avoid clk stretch quirk for BCM2711

[Wolfram Sang]

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On Tue, Aug 27, 2019 at 07:04:15PM +0200, Stefan Wahren wrote:
> The I2C block on the BCM2711 isn't affected by the clk stretching bug.
> So there is no need to apply the corresponding quirk.
> 
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> Reviewed-by: Eric Anholt <eric@anholt.net>

Applied to for-next, thanks!


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Re: [PATCH 3/3] i2c: bcm2835: Add full name of devicetree node to adapter name

[Wolfram Sang]

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On Tue, Aug 27, 2019 at 07:04:16PM +0200, Stefan Wahren wrote:
> Inspired by Lori Hikichi's patch for iproc, this adds the full name of
> the devicetree node to the adapter name. With the introduction of
> BCM2711 it's very difficult to distinguish between the multiple instances.
> 
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>

Applied to for-next, thanks!


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Re: [PATCH 2/3] i2c: bcm2835: Avoid clk stretch quirk for BCM2711

[Matthias Brugger]

On 27/08/2019 19:04, Stefan Wahren wrote:
> The I2C block on the BCM2711 isn't affected by the clk stretching bug.
> So there is no need to apply the corresponding quirk.
> 
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> Reviewed-by: Eric Anholt <eric@anholt.net>
> ---
>  drivers/i2c/busses/i2c-bcm2835.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
> index 67752f7..ab5502f 100644
> --- a/drivers/i2c/busses/i2c-bcm2835.c
> +++ b/drivers/i2c/busses/i2c-bcm2835.c
> @@ -12,6 +12,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
>  #include <linux/module.h>
> +#include <linux/of_device.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
> 
> @@ -389,7 +390,7 @@ static const struct i2c_algorithm bcm2835_i2c_algo = {
>  };
> 
>  /*
> - * This HW was reported to have problems with clock stretching:
> + * The BCM2835 was reported to have problems with clock stretching:
>   * http://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html
>   * https://www.raspberrypi.org/forums/viewtopic.php?p=146272
>   */
> @@ -475,7 +476,7 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
>  	adap->algo = &bcm2835_i2c_algo;
>  	adap->dev.parent = &pdev->dev;
>  	adap->dev.of_node = pdev->dev.of_node;
> -	adap->quirks = &bcm2835_i2c_quirks;
> +	adap->quirks = of_device_get_match_data(&pdev->dev);
> 
>  	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0);
> 
> @@ -501,7 +502,8 @@ static int bcm2835_i2c_remove(struct platform_device *pdev)
>  }
> 
>  static const struct of_device_id bcm2835_i2c_of_match[] = {
> -	{ .compatible = "brcm,bcm2835-i2c" },
> +	{ .compatible = "brcm,bcm2711-i2c" },
> +	{ .compatible = "brcm,bcm2835-i2c", .data = &bcm2835_i2c_quirks },

RPi4 FW seems to still use bcm2835-i2c as compatible in it's DTB blob. Does this
break the driver or is this something we can improve by changing the FW blob in
the future without breaking the driver now?

Regards,
Matthias

>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, bcm2835_i2c_of_match);
> --
> 2.7.4
> 
> 
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