[PATCH 1/2 V3] MXS: Set I2C timing registers for mxs-i2c
From: marex@denx.de (Marek Vasut)
Date: 2012-06-09 11:45:50
Also in:
linux-i2c
Subsystem:
i2c subsystem, i2c subsystem host drivers, open firmware and flattened device tree bindings, the rest · Maintainers:
Andi Shyti, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
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@denx.de> Cc: Detlev Zundel <redacted> CC: Dong Aisheng <redacted> CC: Fabio Estevam <redacted> Cc: Linux ARM kernel <redacted> Cc: linux-i2c at vger.kernel.org CC: Sascha Hauer <s.hauer@pengutronix.de> CC: Shawn Guo <redacted> Cc: Stefano Babic <redacted> CC: Uwe Kleine-K?nig <redacted> Cc: Wolfgang Denk <redacted> Cc: Wolfram Sang <redacted> --- Documentation/devicetree/bindings/i2c/i2c-mxs.txt | 1 + arch/arm/boot/dts/imx28.dtsi | 2 + drivers/i2c/busses/i2c-mxs.c | 55 +++++++++++++++++++++ 3 files changed, 58 insertions(+) V2: Use clock-frequency instead V3: Document that 24MHz clock are the base for i2c speed settings
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..b7d423e 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 +101,25 @@ #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; +}; + +/* Timing values for the default 24MHz clock supplied into the i2c block. */ +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 +135,17 @@ 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 +348,27 @@ 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 +408,11 @@ 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