This patch configures the I2C bus timing registers according
to information passed via DT. Currently, 100kHz and 400kHz
modes are supported.
Signed-off-by: Marek Vasut <marex@xxxxxxx>
Cc: Detlev Zundel <dzu@xxxxxxx>
CC: Dong Aisheng <b29396@xxxxxxxxxxxxx>
CC: Fabio Estevam <fabio.estevam@xxxxxxxxxxxxx>
Cc: Linux ARM kernel <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: linux-i2c@xxxxxxxxxxxxxxx
CC: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
CC: Shawn Guo <shawn.guo@xxxxxxxxxx>
Cc: Stefano Babic <sbabic@xxxxxxx>
CC: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Cc: Wolfgang Denk <wd@xxxxxxx>
Cc: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/i2c/i2c-mxs.txt | 1 +
arch/arm/boot/dts/imx28.dtsi | 2 +
drivers/i2c/busses/i2c-mxs.c | 64 +++++++++++++++++++++
3 files changed, 67 insertions(+)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
index 1bfc02d..790b5c6 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
@@ -4,6 +4,7 @@ Required properties:
- compatible: Should be "fsl,<chip>-i2c"
- reg: Should contain registers location and length
- interrupts: Should contain ERROR and DMA interrupts
+- speed: Speed of the bus in kHz (400 or 100 are supported)
Examples:
diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index 4634cb8..d927155 100644
--- a/arch/arm/boot/dts/imx28.dtsi
+++ b/arch/arm/boot/dts/imx28.dtsi
@@ -381,6 +381,7 @@
compatible = "fsl,imx28-i2c";
reg = <0x80058000 2000>;
interrupts = <111 68>;
+ fsl,speed = <400>;
status = "disabled";
};
@@ -390,6 +391,7 @@
compatible = "fsl,imx28-i2c";
reg = <0x8005a000 2000>;
interrupts = <110 69>;
+ fsl,speed = <400>;
status = "disabled";
};
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 04eb441..fff0a09 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -46,6 +46,10 @@
#define MXS_I2C_CTRL0_DIRECTION 0x00010000
#define MXS_I2C_CTRL0_XFER_COUNT(v) ((v) & 0x0000FFFF)
+#define MXS_I2C_TIMING0 (0x10)
+#define MXS_I2C_TIMING1 (0x20)
+#define MXS_I2C_TIMING2 (0x30)
+
#define MXS_I2C_CTRL1 (0x40)
#define MXS_I2C_CTRL1_SET (0x44)
#define MXS_I2C_CTRL1_CLR (0x48)
@@ -97,6 +101,24 @@
#define MXS_CMD_I2C_READ (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
MXS_I2C_CTRL0_MASTER_MODE)
+struct mxs_i2c_speed_config {
+ uint32_t timing0;
+ uint32_t timing1;
+ uint32_t timing2;
+};
+
+const struct mxs_i2c_speed_config mxs_i2c_95kHz_config = {
+ .timing0 = 0x00780030,
+ .timing1 = 0x00800030,
+ .timing2 = 0x0015000d,
+};
+
+const struct mxs_i2c_speed_config mxs_i2c_400kHz_config = {
+ .timing0 = 0x000f0007,
+ .timing1 = 0x001f000f,
+ .timing2 = 0x0015000d,
+};
+
/**
* struct mxs_i2c_dev - per device, private MXS-I2C data
*
@@ -112,11 +134,17 @@ struct mxs_i2c_dev {
struct completion cmd_complete;
u32 cmd_err;
struct i2c_adapter adapter;
+ const struct mxs_i2c_speed_config *speed;
};
static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
{
stmp_reset_block(i2c->regs);
+
+ writel(i2c->speed->timing0, i2c->regs + MXS_I2C_TIMING0);
+ writel(i2c->speed->timing1, i2c->regs + MXS_I2C_TIMING1);
+ writel(i2c->speed->timing2, i2c->regs + MXS_I2C_TIMING2);
+
writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
i2c->regs + MXS_I2C_QUEUECTRL_SET);
@@ -319,6 +347,38 @@ static const struct i2c_algorithm mxs_i2c_algo = {
.functionality = mxs_i2c_func,
};
+#ifdef CONFIG_OF
+static int mxs_i2c_get_ofdata(struct platform_device *pdev,
+ struct mxs_i2c_dev *i2c)
+{
+ const __be32 *speed;
+ uint32_t speed_khz;
+ struct device_node *node = pdev->dev.of_node;
+
+ if (!node)
+ return -EINVAL;
+
+ i2c->speed = &mxs_i2c_95kHz_config;
+ speed = of_get_property(node, "fsl,speed", NULL);
+ if (!speed)
+ dev_warn(&pdev->dev,
+ "No I2C speed selected, using 100kHz\n");
+
+ speed_khz = be32_to_cpup(speed);
+ if (speed_khz == 400)
+ i2c->speed = &mxs_i2c_400kHz_config;
+ else if (speed_khz != 100)
+ dev_warn(&pdev->dev,
+ "Invalid I2C speed selected, using 100kHz\n");
+
+ return 0;
+}
+#else
+static int mxs_i2c_get_ofdata(struct platform_device *pdev,
+ struct mxs_i2c_dev *i2c)
+{ }
+#endif /* CONFIG_OF */
+
static int __devinit mxs_i2c_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -357,6 +417,10 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
if (err)
return err;
+ err = mxs_i2c_get_ofdata(pdev, i2c);
+ if (err)
+ return err;
+
i2c->dev = dev;
platform_set_drvdata(pdev, i2c);
--
1.7.10
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