Re: [U-Boot] [PATCH 2/5] i2c: omap24xx: Fix waitdelay value for I2C HS

[Heiko Schocher]

Hello Christophe,

Am 17.01.2016 um 12:09 schrieb Christophe Ricard:

After several testings and experiment, it appears that waitdelay calculation
formula was giving different behavior on the i2c status registers.

Experiment shows waitdelay needs to be extended at least 4 times to get
proper results.

Signed-off-by: Christophe Ricard 
---

  drivers/i2c/omap24xx_i2c.c | 18 --
  1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
index f3a4d96..d6e5fe9 100644
--- a/drivers/i2c/omap24xx_i2c.c
+++ b/drivers/i2c/omap24xx_i2c.c
@@ -168,6 +168,13 @@ static int omap24_i2c_setspeed(struct udevice *adap, 
unsigned int speed)
scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;

+#ifdef CONFIG_SYS_I2C
+   adap->speed  = speed;
+   adap->waitdelay = (1000 / speed) * 8; /* wait for 20 
clkperiods */
+#else
+   i2c_bus->clock_frequency = speed;
+   i2c_bus->waitdelay = (1000 / speed) * 8; /* wait for 20 
clkperiods */
+#endif
} else {
/* Standard and fast speed */
psc = omap24_i2c_findpsc(, , speed);
@@ -175,15 +182,15 @@ static int omap24_i2c_setspeed(struct udevice *adap, 
unsigned int speed)
puts("Error : I2C initializing clock\n");
return -1;
}
-   }

  #ifdef CONFIG_SYS_I2C
-   adap->speed  = speed;
-   adap->waitdelay = (1000 / speed) * 2; /* wait for 20 clkperiods */
+   adap->speed  = speed;
+   adap->waitdelay = (1000 / speed) * 2; /* wait for 20 
clkperiods */
  #else
-   i2c_bus->clock_frequency = speed;
-   i2c_bus->waitdelay = (1000 / speed) * 2; /* wait for 20 clkperiods 
*/
+   i2c_bus->clock_frequency = speed;
+   i2c_bus->waitdelay = (1000 / speed) * 2; /* wait for 20 
clkperiods */
  #endif
+   }


You change here only the "speed >= OMAP_I2C_HIGH_SPEED" case ... Is this your 
intention?

If so, please add this info in your commit message.

Beside of this nitpick:

Acked-by: Heiko Schocher 

bye,
Heiko


writew(0, _base->con);
writew(psc, _base->psc);
@@ -467,7 +474,6 @@ static int omap24_i2c_read(struct udevice *adap, uchar 
chip, uint addr,
i2c_bus = dev_get_priv(adap);
i2c_base = i2c_bus->i2c_base;
  #endif
-
if (alen < 0) {
puts("I2C read: addr len < 0\n");
return 1;



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[U-Boot] [PATCH 2/5] i2c: omap24xx: Fix waitdelay value for I2C HS

[Christophe Ricard]

After several testings and experiment, it appears that waitdelay calculation
formula was giving different behavior on the i2c status registers.

Experiment shows waitdelay needs to be extended at least 4 times to get
proper results.

Signed-off-by: Christophe Ricard 
---

 drivers/i2c/omap24xx_i2c.c | 18 --
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
index f3a4d96..d6e5fe9 100644
--- a/drivers/i2c/omap24xx_i2c.c
+++ b/drivers/i2c/omap24xx_i2c.c
@@ -168,6 +168,13 @@ static int omap24_i2c_setspeed(struct udevice *adap, 
unsigned int speed)
scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
 
+#ifdef CONFIG_SYS_I2C
+   adap->speed = speed;
+   adap->waitdelay = (1000 / speed) * 8; /* wait for 20 
clkperiods */
+#else
+   i2c_bus->clock_frequency = speed;
+   i2c_bus->waitdelay = (1000 / speed) * 8; /* wait for 20 
clkperiods */
+#endif
} else {
/* Standard and fast speed */
psc = omap24_i2c_findpsc(, , speed);
@@ -175,15 +182,15 @@ static int omap24_i2c_setspeed(struct udevice *adap, 
unsigned int speed)
puts("Error : I2C initializing clock\n");
return -1;
}
-   }
 
 #ifdef CONFIG_SYS_I2C
-   adap->speed = speed;
-   adap->waitdelay = (1000 / speed) * 2; /* wait for 20 clkperiods */
+   adap->speed = speed;
+   adap->waitdelay = (1000 / speed) * 2; /* wait for 20 
clkperiods */
 #else
-   i2c_bus->clock_frequency = speed;
-   i2c_bus->waitdelay = (1000 / speed) * 2; /* wait for 20 clkperiods 
*/
+   i2c_bus->clock_frequency = speed;
+   i2c_bus->waitdelay = (1000 / speed) * 2; /* wait for 20 
clkperiods */
 #endif
+   }
 
writew(0, _base->con);
writew(psc, _base->psc);
@@ -467,7 +474,6 @@ static int omap24_i2c_read(struct udevice *adap, uchar 
chip, uint addr,
i2c_bus = dev_get_priv(adap);
i2c_base = i2c_bus->i2c_base;
 #endif
-
if (alen < 0) {
puts("I2C read: addr len < 0\n");
return 1;
-- 
2.5.0

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