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path: root/drivers/i2c/mxs_i2c.c
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Diffstat (limited to 'drivers/i2c/mxs_i2c.c')
-rw-r--r--drivers/i2c/mxs_i2c.c134
1 files changed, 67 insertions, 67 deletions
diff --git a/drivers/i2c/mxs_i2c.c b/drivers/i2c/mxs_i2c.c
index 9594008..d3cb727 100644
--- a/drivers/i2c/mxs_i2c.c
+++ b/drivers/i2c/mxs_i2c.c
@@ -29,9 +29,9 @@ static struct mxs_i2c_regs *mxs_i2c_get_base(struct i2c_adapter *adap)
return (struct mxs_i2c_regs *)MXS_I2C0_BASE;
}
-static unsigned int mxs_i2c_get_bus_speed(void)
+static unsigned int mxs_i2c_get_bus_speed(struct i2c_adapter *adap)
{
- struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(NULL);
+ struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
uint32_t clk = mxc_get_clock(MXC_XTAL_CLK);
uint32_t timing0;
@@ -43,11 +43,52 @@ static unsigned int mxs_i2c_get_bus_speed(void)
return clk / ((((timing0 >> 16) - 3) * 2) + 38);
}
-static void mxs_i2c_reset(void)
+static uint mxs_i2c_set_bus_speed(struct i2c_adapter *adap, uint speed)
+{
+ struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
+ /*
+ * The timing derivation algorithm. There is no documentation for this
+ * algorithm available, it was derived by using the scope and fiddling
+ * with constants until the result observed on the scope was good enough
+ * for 20kHz, 50kHz, 100kHz, 200kHz, 300kHz and 400kHz. It should be
+ * possible to assume the algorithm works for other frequencies as well.
+ *
+ * Note it was necessary to cap the frequency on both ends as it's not
+ * possible to configure completely arbitrary frequency for the I2C bus
+ * clock.
+ */
+ uint32_t clk = mxc_get_clock(MXC_XTAL_CLK);
+ uint32_t base = ((clk / speed) - 38) / 2;
+ uint16_t high_count = base + 3;
+ uint16_t low_count = base - 3;
+ uint16_t rcv_count = (high_count * 3) / 4;
+ uint16_t xmit_count = low_count / 4;
+
+ if (speed > 540000) {
+ printf("MXS I2C: Speed too high (%d Hz)\n", speed);
+ return -EINVAL;
+ }
+
+ if (speed < 12000) {
+ printf("MXS I2C: Speed too low (%d Hz)\n", speed);
+ return -EINVAL;
+ }
+
+ writel((high_count << 16) | rcv_count, &i2c_regs->hw_i2c_timing0);
+ writel((low_count << 16) | xmit_count, &i2c_regs->hw_i2c_timing1);
+
+ writel((0x0030 << I2C_TIMING2_BUS_FREE_OFFSET) |
+ (0x0030 << I2C_TIMING2_LEADIN_COUNT_OFFSET),
+ &i2c_regs->hw_i2c_timing2);
+
+ return 0;
+}
+
+static void mxs_i2c_reset(struct i2c_adapter *adap)
{
- struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(NULL);
+ struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
int ret;
- int speed = mxs_i2c_get_bus_speed();
+ int speed = mxs_i2c_get_bus_speed(adap);
ret = mxs_reset_block(&i2c_regs->hw_i2c_ctrl0_reg);
if (ret) {
@@ -62,12 +103,12 @@ static void mxs_i2c_reset(void)
writel(I2C_QUEUECTRL_PIO_QUEUE_MODE, &i2c_regs->hw_i2c_queuectrl_set);
- i2c_set_bus_speed(speed);
+ mxs_i2c_set_bus_speed(adap, speed);
}
-static void mxs_i2c_setup_read(uint8_t chip, int len)
+static void mxs_i2c_setup_read(struct i2c_adapter *adap, uint8_t chip, int len)
{
- struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(NULL);
+ struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
writel(I2C_QUEUECMD_RETAIN_CLOCK | I2C_QUEUECMD_PRE_SEND_START |
I2C_QUEUECMD_MASTER_MODE | I2C_QUEUECMD_DIRECTION |
@@ -83,10 +124,10 @@ static void mxs_i2c_setup_read(uint8_t chip, int len)
writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set);
}
-static int mxs_i2c_write(uchar chip, uint addr, int alen,
- uchar *buf, int blen, int stop)
+static int mxs_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
+ int alen, uchar *buf, int blen, int stop)
{
- struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(NULL);
+ struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
uint32_t data, tmp;
int i, remain, off;
int timeout = MXS_I2C_MAX_TIMEOUT;
@@ -141,9 +182,9 @@ static int mxs_i2c_write(uchar chip, uint addr, int alen,
return 0;
}
-static int mxs_i2c_wait_for_ack(void)
+static int mxs_i2c_wait_for_ack(struct i2c_adapter *adap)
{
- struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(NULL);
+ struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
uint32_t tmp;
int timeout = MXS_I2C_MAX_TIMEOUT;
@@ -175,7 +216,7 @@ static int mxs_i2c_wait_for_ack(void)
return 0;
err:
- mxs_i2c_reset();
+ mxs_i2c_reset(adap);
return 1;
}
@@ -183,26 +224,26 @@ static int mxs_i2c_if_read(struct i2c_adapter *adap, uint8_t chip,
uint addr, int alen, uint8_t *buffer,
int len)
{
- struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(NULL);
+ struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
uint32_t tmp = 0;
int timeout = MXS_I2C_MAX_TIMEOUT;
int ret;
int i;
- ret = mxs_i2c_write(chip, addr, alen, NULL, 0, 0);
+ ret = mxs_i2c_write(adap, chip, addr, alen, NULL, 0, 0);
if (ret) {
debug("MXS I2C: Failed writing address\n");
return ret;
}
- ret = mxs_i2c_wait_for_ack();
+ ret = mxs_i2c_wait_for_ack(adap);
if (ret) {
debug("MXS I2C: Failed writing address\n");
return ret;
}
- mxs_i2c_setup_read(chip, len);
- ret = mxs_i2c_wait_for_ack();
+ mxs_i2c_setup_read(adap, chip, len);
+ ret = mxs_i2c_wait_for_ack(adap);
if (ret) {
debug("MXS I2C: Failed reading address\n");
return ret;
@@ -235,13 +276,13 @@ static int mxs_i2c_if_write(struct i2c_adapter *adap, uint8_t chip,
int len)
{
int ret;
- ret = mxs_i2c_write(chip, addr, alen, buffer, len, 1);
+ ret = mxs_i2c_write(adap, chip, addr, alen, buffer, len, 1);
if (ret) {
debug("MXS I2C: Failed writing address\n");
return ret;
}
- ret = mxs_i2c_wait_for_ack();
+ ret = mxs_i2c_wait_for_ack(adap);
if (ret)
debug("MXS I2C: Failed writing address\n");
@@ -251,58 +292,17 @@ static int mxs_i2c_if_write(struct i2c_adapter *adap, uint8_t chip,
static int mxs_i2c_probe(struct i2c_adapter *adap, uint8_t chip)
{
int ret;
- ret = mxs_i2c_write(chip, 0, 1, NULL, 0, 1);
+ ret = mxs_i2c_write(adap, chip, 0, 1, NULL, 0, 1);
if (!ret)
- ret = mxs_i2c_wait_for_ack();
- mxs_i2c_reset();
+ ret = mxs_i2c_wait_for_ack(adap);
+ mxs_i2c_reset(adap);
return ret;
}
-static uint mxs_i2c_set_bus_speed(struct i2c_adapter *adap, uint speed)
-{
- struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(NULL);
- /*
- * The timing derivation algorithm. There is no documentation for this
- * algorithm available, it was derived by using the scope and fiddling
- * with constants until the result observed on the scope was good enough
- * for 20kHz, 50kHz, 100kHz, 200kHz, 300kHz and 400kHz. It should be
- * possible to assume the algorithm works for other frequencies as well.
- *
- * Note it was necessary to cap the frequency on both ends as it's not
- * possible to configure completely arbitrary frequency for the I2C bus
- * clock.
- */
- uint32_t clk = mxc_get_clock(MXC_XTAL_CLK);
- uint32_t base = ((clk / speed) - 38) / 2;
- uint16_t high_count = base + 3;
- uint16_t low_count = base - 3;
- uint16_t rcv_count = (high_count * 3) / 4;
- uint16_t xmit_count = low_count / 4;
-
- if (speed > 540000) {
- printf("MXS I2C: Speed too high (%d Hz)\n", speed);
- return -EINVAL;
- }
-
- if (speed < 12000) {
- printf("MXS I2C: Speed too low (%d Hz)\n", speed);
- return -EINVAL;
- }
-
- writel((high_count << 16) | rcv_count, &i2c_regs->hw_i2c_timing0);
- writel((low_count << 16) | xmit_count, &i2c_regs->hw_i2c_timing1);
-
- writel((0x0030 << I2C_TIMING2_BUS_FREE_OFFSET) |
- (0x0030 << I2C_TIMING2_LEADIN_COUNT_OFFSET),
- &i2c_regs->hw_i2c_timing2);
-
- return 0;
-}
-
static void mxs_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
{
- mxs_i2c_reset();
- i2c_set_bus_speed(speed);
+ mxs_i2c_reset(adap);
+ mxs_i2c_set_bus_speed(adap, speed);
return;
}