[PATCH v4 0/7] Add support for MSCC Ocelot i2c

[PATCH v4 0/7] Add support for MSCC Ocelot i2c

[Alexandre Belloni]

Hello,

Because the designware IP was not able to handle the SDA hold time before
version 1.11a, MSCC has its own implementation. Add support for it and then add
i2c on ocelot boards.

I would expect patches 1 to 5 to go through the i2c tree and 6-7 through
the mips tree once patch 4 has been reviewed by the DT maintainers.

This is based on top of i2c-next

Changes in v4:
 - collected review and ack tags
 - split bindings to a separate patch

Changes in v3:
 - collected review tags
 - fixed build warnings on 64bit machines

Changes in v2:
 - removed first patch as a similar one is in i2c-next
 - rebase on top of i2c-next
 - Added two patches to implement ideas from Andy


Alexandre Belloni (7):
  i2c: designware: use generic table matching
  i2c: designware: move #ifdef CONFIG_OF to the top
  i2c: designware: allow IP specific sda_hold_time
  i2c: designware: document MSCC Ocelot bindings
  i2c: designware: add MSCC Ocelot support
  MIPS: dts: mscc: Add i2c on ocelot
  MIPS: dts: mscc: enable i2c on ocelot_pcb123

 .../bindings/i2c/i2c-designware.txt           |  7 ++-
 arch/mips/boot/dts/mscc/ocelot.dtsi           | 18 ++++++
 arch/mips/boot/dts/mscc/ocelot_pcb123.dts     |  6 ++
 drivers/i2c/busses/i2c-designware-common.c    |  2 +
 drivers/i2c/busses/i2c-designware-core.h      |  4 ++
 drivers/i2c/busses/i2c-designware-platdrv.c   | 63 +++++++++++++++----
 6 files changed, 86 insertions(+), 14 deletions(-)

-- 
2.18.0

[PATCH v4 1/7] i2c: designware: use generic table matching

[Alexandre Belloni]

Switch to device_get_match_data in probe to match the device specific data
instead of using the acpi specific function.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/i2c/busses/i2c-designware-platdrv.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index fc1462601b16..d5936c32c075 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -99,7 +99,6 @@ static int dw_i2c_acpi_configure(struct platform_device *pdev)
 	struct i2c_timings *t = &dev->timings;
 	u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0;
 	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
-	const struct acpi_device_id *id;
 	struct acpi_device *adev;
 	const char *uid;
 
@@ -132,10 +131,6 @@ static int dw_i2c_acpi_configure(struct platform_device *pdev)
 		break;
 	}
 
-	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
-	if (id && id->driver_data)
-		dev->flags |= (u32)id->driver_data;
-
 	if (acpi_bus_get_device(handle, &adev))
 		return -ENODEV;
 
@@ -304,6 +299,8 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	else
 		t->bus_freq_hz = 400000;
 
+	dev->flags |= (uintptr_t)device_get_match_data(&pdev->dev);
+
 	if (has_acpi_companion(&pdev->dev))
 		dw_i2c_acpi_configure(pdev);
 
-- 
2.18.0

[PATCH v4 2/7] i2c: designware: move #ifdef CONFIG_OF to the top

[Alexandre Belloni]

Move the #ifdef CONFIG_OF section to the top of the file, after the ACPI
section so functions defined there can be used in dw_i2c_plat_probe.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/i2c/busses/i2c-designware-platdrv.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index d5936c32c075..776d4354f366 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -169,6 +169,14 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
 }
 #endif
 
+#ifdef CONFIG_OF
+static const struct of_device_id dw_i2c_of_match[] = {
+	{ .compatible = "snps,designware-i2c", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
+#endif
+
 static void i2c_dw_configure_master(struct dw_i2c_dev *dev)
 {
 	struct i2c_timings *t = &dev->timings;
@@ -403,14 +411,6 @@ static int dw_i2c_plat_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_OF
-static const struct of_device_id dw_i2c_of_match[] = {
-	{ .compatible = "snps,designware-i2c", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
-#endif
-
 #ifdef CONFIG_PM_SLEEP
 static int dw_i2c_plat_prepare(struct device *dev)
 {
-- 
2.18.0

[PATCH v4 3/7] i2c: designware: allow IP specific sda_hold_time

[Alexandre Belloni]

Because some old designware IPs were not supporting setting an SDA hold
time, vendors developed their own solution. Add a way for the final driver
to provide its own SDA hold time handling.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/i2c/busses/i2c-designware-common.c | 2 ++
 drivers/i2c/busses/i2c-designware-core.h   | 1 +
 2 files changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index bcc1bcbf0350..4f4bcefbf404 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -214,6 +214,8 @@ int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev)
 		dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n",
 			dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK,
 			dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT);
+	} else if (dev->set_sda_hold_time) {
+		dev->set_sda_hold_time(dev);
 	} else if (dev->sda_hold_time) {
 		dev_warn(dev->dev,
 			"Hardware too old to adjust SDA hold time.\n");
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index cdba58a3e359..ad4e9619d365 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -282,6 +282,7 @@ struct dw_i2c_dev {
 	void			(*disable)(struct dw_i2c_dev *dev);
 	void			(*disable_int)(struct dw_i2c_dev *dev);
 	int			(*init)(struct dw_i2c_dev *dev);
+	int			(*set_sda_hold_time)(struct dw_i2c_dev *dev);
 	int			mode;
 	struct i2c_bus_recovery_info rinfo;
 };
-- 
2.18.0

[PATCH v4 4/7] i2c: designware: document MSCC Ocelot bindings

[Alexandre Belloni]

Document bindings for the Microsemi Ocelot integration of the Designware
I2C controller.

Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 Documentation/devicetree/bindings/i2c/i2c-designware.txt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index fbb0a6d8b964..3e4bcc2fb6f7 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
@@ -3,6 +3,7 @@
 Required properties :
 
  - compatible : should be "snps,designware-i2c"
+                or "mscc,ocelot-i2c" with "snps,designware-i2c" for fallback
  - reg : Offset and length of the register set for the device
  - interrupts : <IRQ> where IRQ is the interrupt number.
 
@@ -11,8 +12,12 @@ Recommended properties :
  - clock-frequency : desired I2C bus clock frequency in Hz.
 
 Optional properties :
+ - reg : for "mscc,ocelot-i2c", a second register set to configure the SDA hold
+   time, named ICPU_CFG:TWI_DELAY in the datasheet.
+
  - i2c-sda-hold-time-ns : should contain the SDA hold time in nanoseconds.
-   This option is only supported in hardware blocks version 1.11a or newer.
+   This option is only supported in hardware blocks version 1.11a or newer and
+   on Microsemi SoCs ("mscc,ocelot-i2c" compatible).
 
  - i2c-scl-falling-time-ns : should contain the SCL falling time in nanoseconds.
    This value which is by default 300ns is used to compute the tLOW period.
-- 
2.18.0

[PATCH v4 5/7] i2c: designware: add MSCC Ocelot support

[Alexandre Belloni]

The Microsemi Ocelot I2C controller is a designware IP. It also has a
second set of registers to allow tweaking SDA hold time and spike
filtering.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/i2c/busses/i2c-designware-core.h    |  3 ++
 drivers/i2c/busses/i2c-designware-platdrv.c | 40 +++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index ad4e9619d365..f7883224e1af 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -238,6 +238,7 @@
 struct dw_i2c_dev {
 	struct device		*dev;
 	void __iomem		*base;
+	void __iomem		*ext;
 	struct completion	cmd_complete;
 	struct clk		*clk;
 	struct reset_control	*rst;
@@ -292,6 +293,8 @@ struct dw_i2c_dev {
 #define ACCESS_INTR_MASK	0x00000004
 
 #define MODEL_CHERRYTRAIL	0x00000100
+#define MODEL_MSCC_OCELOT	0x00000200
+#define MODEL_MASK		0x00000f00
 
 u32 dw_readl(struct dw_i2c_dev *dev, int offset);
 void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset);
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 776d4354f366..0d9bfa45550d 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -170,11 +170,48 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
 #endif
 
 #ifdef CONFIG_OF
+#define MSCC_ICPU_CFG_TWI_DELAY		0x0
+#define MSCC_ICPU_CFG_TWI_DELAY_ENABLE	BIT(0)
+#define MSCC_ICPU_CFG_TWI_SPIKE_FILTER	0x4
+
+static int mscc_twi_set_sda_hold_time(struct dw_i2c_dev *dev)
+{
+	writel((dev->sda_hold_time << 1) | MSCC_ICPU_CFG_TWI_DELAY_ENABLE,
+	       dev->ext + MSCC_ICPU_CFG_TWI_DELAY);
+
+	return 0;
+}
+
+int dw_i2c_of_configure(struct platform_device *pdev)
+{
+	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+	struct resource *mem;
+
+	switch (dev->flags & MODEL_MASK) {
+	case MODEL_MSCC_OCELOT:
+		mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+		dev->ext = devm_ioremap_resource(&pdev->dev, mem);
+		if (!IS_ERR(dev->ext))
+			dev->set_sda_hold_time = mscc_twi_set_sda_hold_time;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
 static const struct of_device_id dw_i2c_of_match[] = {
 	{ .compatible = "snps,designware-i2c", },
+	{ .compatible = "mscc,ocelot-i2c", .data = (void *)MODEL_MSCC_OCELOT },
 	{},
 };
 MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
+#else
+static inline int dw_i2c_of_configure(struct platform_device *pdev)
+{
+	return -ENODEV;
+}
 #endif
 
 static void i2c_dw_configure_master(struct dw_i2c_dev *dev)
@@ -309,6 +346,9 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 
 	dev->flags |= (uintptr_t)device_get_match_data(&pdev->dev);
 
+	if (pdev->dev.of_node)
+		dw_i2c_of_configure(pdev);
+
 	if (has_acpi_companion(&pdev->dev))
 		dw_i2c_acpi_configure(pdev);
 
-- 
2.18.0

[PATCH v4 6/7] MIPS: dts: mscc: Add i2c on ocelot

[Alexandre Belloni]

Ocelot has an i2c controller, add it. There is only one possible pinmux
configuration so add it as well.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 arch/mips/boot/dts/mscc/ocelot.dtsi | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/mips/boot/dts/mscc/ocelot.dtsi b/arch/mips/boot/dts/mscc/ocelot.dtsi
index 4f33dbc67348..34093acebc0d 100644
--- a/arch/mips/boot/dts/mscc/ocelot.dtsi
+++ b/arch/mips/boot/dts/mscc/ocelot.dtsi
@@ -78,6 +78,19 @@
 			status = "disabled";
 		};
 
+		i2c: i2c@100400 {
+			compatible = "mscc,ocelot-i2c", "snps,designware-i2c";
+			pinctrl-0 = <&i2c_pins>;
+			pinctrl-names = "default";
+			reg = <0x100400 0x100>, <0x198 0x8>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			interrupts = <8>;
+			clocks = <&ahb_clk>;
+
+			status = "disabled";
+		};
+
 		uart2: serial@100800 {
 			pinctrl-0 = <&uart2_pins>;
 			pinctrl-names = "default";
@@ -178,6 +191,11 @@
 				pins = "GPIO_12", "GPIO_13";
 				function = "uart2";
 			};
+
+			i2c_pins: i2c-pins {
+				pins = "GPIO_16", "GPIO_17";
+				function = "twi";
+			};
 		};
 
 		mdio0: mdio@107009c {
-- 
2.18.0

[PATCH v4 7/7] MIPS: dts: mscc: enable i2c on ocelot_pcb123

[Alexandre Belloni]

Enable the i2c controller on ocelot PCB123. While there are no i2c devices
on the board itself, it can be used to control the SFP transceivers.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 arch/mips/boot/dts/mscc/ocelot_pcb123.dts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/mips/boot/dts/mscc/ocelot_pcb123.dts b/arch/mips/boot/dts/mscc/ocelot_pcb123.dts
index 4ccd65379059..336c859a9bbe 100644
--- a/arch/mips/boot/dts/mscc/ocelot_pcb123.dts
+++ b/arch/mips/boot/dts/mscc/ocelot_pcb123.dts
@@ -26,6 +26,12 @@
 	status = "okay";
 };
 
+&i2c {
+	clock-frequency = <100000>;
+	i2c-sda-hold-time-ns = <300>;
+	status = "okay";
+};
+
 &mdio0 {
 	status = "okay";
 };
-- 
2.18.0

Re: [PATCH v4 0/7] Add support for MSCC Ocelot i2c

[Jarkko Nikula]

On 08/16/2018 11:45 AM, Alexandre Belloni wrote:
> Hello,
> 
> Because the designware IP was not able to handle the SDA hold time before
> version 1.11a, MSCC has its own implementation. Add support for it and then add
> i2c on ocelot boards.
> 
> I would expect patches 1 to 5 to go through the i2c tree and 6-7 through
> the mips tree once patch 4 has been reviewed by the DT maintainers.
> 
For the patches 1-3 and 5/7 that touch i2c-designware:

Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>

Re: [PATCH v4 4/7] i2c: designware: document MSCC Ocelot bindings

[Rob Herring]

Hi, this email is from Rob's (experimental) review bot. I found a couple
of common problems with your patch. Please see below.

On Thu, 16 Aug 2018 10:45:18 +0200, Alexandre Belloni wrote:
> Document bindings for the Microsemi Ocelot integration of the Designware
> I2C controller.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The preferred subject prefix is "dt-bindings: <binding dir>: ...".

> ---
>  Documentation/devicetree/bindings/i2c/i2c-designware.txt | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 

Re: [PATCH v4 4/7] i2c: designware: document MSCC Ocelot bindings

[Rob Herring]

On Thu, Aug 16, 2018 at 10:45:18AM +0200, Alexandre Belloni wrote:
> Document bindings for the Microsemi Ocelot integration of the Designware
> I2C controller.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-designware.txt | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

No need to re-spin just for the subject.

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

Re: [PATCH v4 4/7] i2c: designware: document MSCC Ocelot bindings

[Alexandre Belloni]

On 20/08/2018 13:13:41-0500, Rob Herring wrote:
> On Thu, Aug 16, 2018 at 10:45:18AM +0200, Alexandre Belloni wrote:
> > Document bindings for the Microsemi Ocelot integration of the Designware
> > I2C controller.
> > 
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> > ---
> >  Documentation/devicetree/bindings/i2c/i2c-designware.txt | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> No need to re-spin just for the subject.
> 

Great, thanks a lot!

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

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com