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Subject[PATCH v3 4/6] i2c: designware: add MSCC Ocelot support
Date
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.

Cc: Rob Herring <robh+dt@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
.../bindings/i2c/i2c-designware.txt | 9 ++++-
drivers/i2c/busses/i2c-designware-core.h | 3 ++
drivers/i2c/busses/i2c-designware-platdrv.c | 40 +++++++++++++++++++
3 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index fbb0a6d8b964..7886f2dc6675 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
@@ -2,7 +2,8 @@

Required properties :

- - compatible : should be "snps,designware-i2c"
+ - compatible : should be "snps,designware-i2c" or "mscc,ocelot-i2c" followed by
+ "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.
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 870444bbbcc4..5e240ce9968e 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -225,6 +225,7 @@
struct dw_i2c_dev {
struct device *dev;
void __iomem *base;
+ void __iomem *ext;
struct completion cmd_complete;
struct clk *clk;
struct reset_control *rst;
@@ -279,6 +280,8 @@ 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 1bcaab777a2e..39aab03cb416 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -157,11 +157,48 @@ 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)
@@ -296,6 +333,9 @@ 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
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