On 06/18/2015 05:00 AM, Sekhar Nori wrote:
On Thursday 18 June 2015 02:23 PM, Alexander Sverdlin wrote:
According to KeyStone Architecture I2C User Guide,
module clock frequency
master clock frequency = ----------------------
(ICCL + 6) + (ICCH + 6)
i.e. "d" in i2c_davinci_calc_clk_dividers() should be fixed and
not dependent from module clock prescaler PSC on these SoCs.
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
---
RFC: If someone from TI has an idea how to improve the coverage of future Keystone
revisions -- hints/patches are welcome. The current ID check is based on
Davinci/Keystone datasheets and is at least working on real Keystone II.
+ Murali who works on Keystone devices in TI.
+ Grygorii
+ Grygorii has been involved in the Keystone related enhancement and
reviewing prior patches. Need to have his ack for this change
Murali
drivers/i2c/busses/i2c-davinci.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 4a110af..3d78f6a 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -60,6 +60,8 @@
#define DAVINCI_I2C_IVR_REG 0x28
#define DAVINCI_I2C_EMDR_REG 0x2c
#define DAVINCI_I2C_PSC_REG 0x30
+#define DAVINCI_I2C_ICPID1_REG 0x34
+#define DAVINCI_I2C_ICPID2_REG 0x38
#define DAVINCI_I2C_FUNC_REG 0x48
#define DAVINCI_I2C_DIR_REG 0x4c
#define DAVINCI_I2C_DIN_REG 0x50
@@ -203,6 +205,9 @@ static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
* where if PSC == 0, d = 7,
* if PSC == 1, d = 6
* if PSC > 1 , d = 5
+ *
+ * Note:
+ * d is always 6 on Keystone I2C controller
*/
/* get minimum of 7 MHz clock, but max of 12 MHz */
@@ -211,6 +216,11 @@ static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
psc++; /* better to run under spec than over */
d = (psc >= 2) ? 5 : 7 - psc;
+ if (davinci_i2c_read_reg(dev, DAVINCI_I2C_ICPID2_REG) == 0x2206) {
+ dev_dbg(dev->dev, "Keystone SoC detected\n");
+ d = 6;
+ }
I think its better to use a different compatible string for i2c on
keystone devices rather than using a fixed hardcoded IP version.
Thanks,
Sekhar
--
Murali Karicheri
Linux Kernel, Keystone
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