[U-Boot] [PATCH 3/4] i2c: mxs: Pass the i2c_adapter around
Marek Vasut
marex at denx.de
Mon Oct 20 00:23:42 CEST 2014
This patch permeates the struct i2c_adapter throughout the driver,
so that it can be used to determine which adapter should be used.
Note that the driver still supports only one adapter. Note that
the patch does shuffle mxs_i2c_set_bus_speed() to the top of the
driver, but the function remains unchanged.
Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Stefano Babic <sbabic at denx.de>
Cc: Heiko Schocher <hs at denx.de>
---
drivers/i2c/mxs_i2c.c | 134 +++++++++++++++++++++++++-------------------------
1 file 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;
}
--
2.1.1
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