Previous patch for this driver breaks i2c initialization.
commit 8bcf12ccce89 ("i2c: mvtwsi.c: Avoid NULL dereference")
If actual_speed is passed as NULL in this function:
static void __twsi_i2c_init(struct mvtwsi_registers *twsi, int speed,
int slaveadd, uint *actual_speed)
than __twsi_i2c_set_bus_speed never get called. This causes i2c clock
to run on default speed - 2MHz (measured with oscilloscope). This is issue
on some boards, sunxi for example, since on I2C0 bus PMU is connected.
The bootlogs with and without the patch are as follows:
Wihtout the patch:
U-Boot SPL 2018.03-rc2 (Feb 13 2018 - 09:23:17 +0200)
DRAM: 1024 MiB
Failed to set core voltage! Can't set CPU frequency
Trying to boot from FEL
U-Boot 2018.03-rc2 (Feb 13 2018 - 09:23:17 +0200) Allwinner Technology
CPU: Allwinner A20 (SUN7I)
Model: Olimex A20-OLinuXino-LIME2
I2C: ready
DRAM: 1 GiB
MMC: SUNXI SD/MMC: 0
With the patch:
U-Boot SPL 2018.03-rc2-00001-g838ff85 (Feb 13 2018 - 09:24:34 +0200)
DRAM: 1024 MiB
CPU: 912000000Hz, AXI/AHB/APB: 3/2/2
Trying to boot from FEL
U-Boot 2018.03-rc2-00001-g838ff85 (Feb 13 2018 - 09:24:34 +0200) Allwinner
Technology
CPU: Allwinner A20 (SUN7I)
Model: Olimex A20-OLinuXino-LIME2
I2C: ready
DRAM: 1 GiB
MMC: SUNXI SD/MMC: 0
Signed-off-by: Stefan Mavrodiev <ste...@olimex.com>
---
drivers/i2c/mvtwsi.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/mvtwsi.c b/drivers/i2c/mvtwsi.c
index 30bee0d..38bca89 100644
--- a/drivers/i2c/mvtwsi.c
+++ b/drivers/i2c/mvtwsi.c
@@ -487,11 +487,14 @@ static uint __twsi_i2c_set_bus_speed(struct
mvtwsi_registers *twsi,
static void __twsi_i2c_init(struct mvtwsi_registers *twsi, int speed,
int slaveadd, uint *actual_speed)
{
+ uint tmp_speed;
+
/* Reset controller */
twsi_reset(twsi);
/* Set speed */
+ tmp_speed = __twsi_i2c_set_bus_speed(twsi, speed);
if (actual_speed)
- *actual_speed = __twsi_i2c_set_bus_speed(twsi, speed);
+ *actual_speed = tmp_speed;
/* Set slave address; even though we don't use it */
writel(slaveadd, &twsi->slave_address);
writel(0, &twsi->xtnd_slave_addr);
--
2.7.4
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