diff options
| author | Gregory CLEMENT <gregory.clement@free-electrons.com> | 2013-08-22 14:19:06 (GMT) |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2013-08-23 08:15:51 (GMT) |
| commit | c1d15b68aab86f1f3b602fa65e7618c0065d46e6 (patch) | |
| tree | 929537c122d396ce4e763b1e73a199a64eb70663 | |
| parent | 930ab3d403ae43f19d7e6d972139e02c9b8a5ec6 (diff) | |
| download | linux-c1d15b68aab86f1f3b602fa65e7618c0065d46e6.tar.xz | |
i2c: mv64xxx: Fix timing issue on Armada XP (errata FE-8471889)
All the Armada XP (mv78230, mv78260 and mv78460) have a silicon issue
in the I2C controller which violate the i2c repeated start
timing. The I2C standard requires a minimum of 4.7us for the repeated
start condition whereas the I2C controller of the Armada XP this time
is 2.9us.
So this patch adds a 5us delay for the start case only if the
the compatible i2c-mv78230 is set.
Based on the initals patches from Zbigniew Bodek
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Zbigniew Bodek <zbb@semihalf.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
| -rw-r--r-- | drivers/i2c/busses/i2c-mv64xxx.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 2404c4e..bc60f9a 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -24,6 +24,7 @@ #include <linux/of_i2c.h> #include <linux/clk.h> #include <linux/err.h> +#include <linux/delay.h> #define MV64XXX_I2C_ADDR_ADDR(val) ((val & 0x7f) << 1) #define MV64XXX_I2C_BAUD_DIV_N(val) (val & 0x7) @@ -147,6 +148,8 @@ struct mv64xxx_i2c_data { struct i2c_msg *msg; struct i2c_adapter adapter; bool offload_enabled; +/* 5us delay in order to avoid repeated start timing violation */ + bool errata_delay; }; static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = { @@ -440,6 +443,9 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) /* Setup for the next message */ mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msgs); } + if (drv_data->errata_delay) + udelay(5); + /* * We're never at the start of the message here, and by this * time it's already too late to do any protocol mangling. @@ -499,6 +505,9 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP, drv_data->reg_base + drv_data->reg_offsets.control); drv_data->block = 0; + if (drv_data->errata_delay) + udelay(5); + wake_up(&drv_data->waitq); break; @@ -766,10 +775,12 @@ mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data, /* * For controllers embedded in new SoCs activate the - * Transaction Generator support. + * Transaction Generator support and the errata fix. */ - if (of_device_is_compatible(np, "marvell,mv78230-i2c")) + if (of_device_is_compatible(np, "marvell,mv78230-i2c")) { drv_data->offload_enabled = true; + drv_data->errata_delay = true; + } out: return rc; |