The clkhi and clklo ratio was not very precise before that can make the
time of START/STOP/HIGH LEVEL out of specification.
Therefore, the calculation of these times has been modified in this patch.
At the same time, the mode rate definition of i2c is corrected.
Signed-off-by: Clark Wang <[email protected]>
Reviewed-by: Fugang Duan <[email protected]>
---
V2 changes:
- No change.
---
drivers/i2c/busses/i2c-imx-lpi2c.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 77dd6ee5a4a8..d124c4000823 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -73,17 +73,17 @@
#define MCFGR1_IGNACK BIT(9)
#define MRDR_RXEMPTY BIT(14)
-#define I2C_CLK_RATIO 2
+#define I2C_CLK_RATIO 24 / 59
#define CHUNK_DATA 256
#define I2C_PM_TIMEOUT 1000 /* ms */
enum lpi2c_imx_mode {
- STANDARD, /* 100+Kbps */
- FAST, /* 400+Kbps */
- FAST_PLUS, /* 1.0+Mbps */
- HS, /* 3.4+Mbps */
- ULTRA_FAST, /* 5.0+Mbps */
+ STANDARD, /* <=100Kbps */
+ FAST, /* <=400Kbps */
+ FAST_PLUS, /* <=1.0Mbps */
+ HS, /* <=3.4Mbps */
+ ULTRA_FAST, /* <=5.0Mbps */
};
enum lpi2c_imx_pincfg {
@@ -156,13 +156,13 @@ static void lpi2c_imx_set_mode(struct lpi2c_imx_struct *lpi2c_imx)
unsigned int bitrate = lpi2c_imx->bitrate;
enum lpi2c_imx_mode mode;
- if (bitrate < I2C_MAX_FAST_MODE_FREQ)
+ if (bitrate <= I2C_MAX_STANDARD_MODE_FREQ)
mode = STANDARD;
- else if (bitrate < I2C_MAX_FAST_MODE_PLUS_FREQ)
+ else if (bitrate <= I2C_MAX_FAST_MODE_FREQ)
mode = FAST;
- else if (bitrate < I2C_MAX_HIGH_SPEED_MODE_FREQ)
+ else if (bitrate <= I2C_MAX_FAST_MODE_PLUS_FREQ)
mode = FAST_PLUS;
- else if (bitrate < I2C_MAX_ULTRA_FAST_MODE_FREQ)
+ else if (bitrate <= I2C_MAX_HIGH_SPEED_MODE_FREQ)
mode = HS;
else
mode = ULTRA_FAST;
@@ -209,7 +209,8 @@ static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
} while (1);
}
-/* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
+/* CLKLO = (1 - I2C_CLK_RATIO) * clk_cycle, SETHOLD = CLKHI, DATAVD = CLKHI/2
+ CLKHI = I2C_CLK_RATIO * clk_cycle */
static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
{
u8 prescale, filt, sethold, clkhi, clklo, datavd;
@@ -232,8 +233,8 @@ static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
for (prescale = 0; prescale <= 7; prescale++) {
clk_cycle = clk_rate / ((1 << prescale) * lpi2c_imx->bitrate)
- - 3 - (filt >> 1);
- clkhi = (clk_cycle + I2C_CLK_RATIO) / (I2C_CLK_RATIO + 1);
+ - (2 + filt) / (1 << prescale);
+ clkhi = clk_cycle * I2C_CLK_RATIO;
clklo = clk_cycle - clkhi;
if (clklo < 64)
break;
--
2.25.1