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Diffstat (limited to 'drivers/i2c/busses/i2c-mxs.c')
-rw-r--r--drivers/i2c/busses/i2c-mxs.c68
1 files changed, 67 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 04eb441..088c5c1 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 +101,35 @@
#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.
+ *
+ * The bus can operate at 95kHz or at 400kHz with the following timing
+ * register configurations. The 100kHz mode isn't present because it's
+ * values are not stated in the i.MX233/i.MX28 datasheet. The 95kHz mode
+ * shall be close enough replacement. Therefore when the bus is configured
+ * for 100kHz operation, 95kHz timing settings are actually loaded.
+ *
+ * For details, see i.MX233 [25.4.2 - 25.4.4] and i.MX28 [27.5.2 - 27.5.4].
+ */
+static const struct mxs_i2c_speed_config mxs_i2c_95kHz_config = {
+ .timing0 = 0x00780030,
+ .timing1 = 0x00800030,
+ .timing2 = 0x00300030,
+};
+
+static const struct mxs_i2c_speed_config mxs_i2c_400kHz_config = {
+ .timing0 = 0x000f0007,
+ .timing1 = 0x001f000f,
+ .timing2 = 0x00300030,
+};
+
/**
* struct mxs_i2c_dev - per device, private MXS-I2C data
*
@@ -112,11 +145,17 @@ 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);
@@ -193,7 +232,7 @@ static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c)
static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len)
{
- u32 data;
+ u32 uninitialized_var(data);
int i;
for (i = 0; i < len; i++) {
@@ -319,6 +358,28 @@ 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;
+ int ret;
+
+ 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, "Unsupported 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 +419,11 @@ 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 */
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