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 | 54 +++++++++++++++++++++
3 files changed, 57 insertions(+)
V2: Use clock-frequency instead
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
index 1bfc02d..d2bf750 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
+- clock-frequency: desired I2C bus clock frequency in Hz.
Examples:
diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index a89da5a..714e63c 100644
--- a/arch/arm/boot/dts/imx28.dtsi
+++ b/arch/arm/boot/dts/imx28.dtsi
@@ -398,6 +398,7 @@
compatible = "fsl,imx28-i2c";
reg = <0x80058000 2000>;
interrupts = <111 68>;
+ clock-frequency = <400000>;
status = "disabled";
};
@@ -407,6 +408,7 @@
compatible = "fsl,imx28-i2c";
reg = <0x8005a000 2000>;
interrupts = <110 69>;
+ clock-frequency = <400000>;
status = "disabled";
};
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 04eb441..b4d083f 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 +347,27 @@ static const struct i2c_algorithm mxs_i2c_algo = {
.functionality = mxs_i2c_func,
};
+static int mxs_i2c_get_ofdata(struct mxs_i2c_dev *i2c)
+{
+ uint32_t speed;
+ struct device *dev = i2c->dev;
+ struct device_node *node = dev->of_node;
+
+ if (!node)
+ return -EINVAL;
+
+ i2c->speed = &mxs_i2c_95kHz_config;
+ ret = of_property_read_u32(node, "clock-frequency", &speed);
+ if (ret)
+ dev_warn(dev, "No I2C speed selected, using 100kHz\n");
+ else if (speed == 400000)
+ i2c->speed = &mxs_i2c_400kHz_config;
+ else if (speed != 100000)
+ dev_warn(dev, "Invalid I2C speed selected, using 100kHz\n");
+
+ return 0;
+}
+
static int __devinit mxs_i2c_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -358,6 +407,11 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
return err;
i2c->dev = dev;
+
+ err = mxs_i2c_get_ofdata(i2c);
+ if (err)
+ return err;
+
platform_set_drvdata(pdev, i2c);
/* Do reset to enforce correct startup after pinmuxing */
--
1.7.10
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