diff options
| author | Shyam Sundar S K <Shyam-sundar.S-k@amd.com> | 2023-01-24 12:11:27 +0100 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2023-01-28 20:05:32 +0100 |
| commit | 60a1f9f28660657f863a3846a64b6c3cbb18f07d (patch) | |
| tree | 3855d2cafaa5bb6a39501f906b765254428906e6 /drivers/i2c | |
| parent | i2c: gpio: support write-only sda/scl w/o pull-up (diff) | |
| download | linux-60a1f9f28660657f863a3846a64b6c3cbb18f07d.tar.xz linux-60a1f9f28660657f863a3846a64b6c3cbb18f07d.zip | |
i2c: designware: add a new bit check for IC_CON control
On some AMD platforms, based on the new designware datasheet,
BIOS sets the BIT(11) within the IC_CON register to advertise
the "bus clear feature capability".
AMD/Designware datasheet says:
Bit(11) BUS_CLEAR_FEATURE_CTRL. Read-write,Volatile. Reset: 0.
Description: In Master mode:
- 1'b1: Bus Clear Feature is enabled.
- 1'b0: Bus Clear Feature is Disabled.
In Slave mode, this register bit is not applicable.
On AMD platform designs:
1. BIOS programs the BUS_CLEAR_FEATURE_CTRL and enables the detection
of SCL/SDA stuck low.
2. Whenever the stuck low is detected, the SMU FW shall do the bus
recovery procedure.
Currently, the way in which the "master_cfg" is built in the driver, it
overrides the BUS_CLEAR_FEATURE_CTRL advertised by BIOS and the SMU FW
cannot initiate the bus recovery if the stuck low is detected.
Hence add a check in i2c_dw_probe_master() that if the BIOS
advertises the bus clear feature, let driver not ignore it and
adapt accordingly.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-core.h | 1 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-master.c | 20 |
2 files changed, 21 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index 6bc2edec14f2..932395ddd42b 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -37,6 +37,7 @@ #define DW_IC_CON_STOP_DET_IFADDRESSED BIT(7) #define DW_IC_CON_TX_EMPTY_CTRL BIT(8) #define DW_IC_CON_RX_FIFO_FULL_HLD_CTRL BIT(9) +#define DW_IC_CON_BUS_CLEAR_CTRL BIT(11) #define DW_IC_DATA_CMD_DAT GENMASK(7, 0) diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c index 45f569155bfe..3be7581ee3fb 100644 --- a/drivers/i2c/busses/i2c-designware-master.c +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -865,6 +865,7 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev) { struct i2c_adapter *adap = &dev->adapter; unsigned long irq_flags; + unsigned int ic_con; int ret; init_completion(&dev->cmd_complete); @@ -884,6 +885,25 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev) if (ret) return ret; + /* Lock the bus for accessing DW_IC_CON */ + ret = i2c_dw_acquire_lock(dev); + if (ret) + return ret; + + /* + * On AMD platforms BIOS advertises the bus clear feature + * and enables the SCL/SDA stuck low. SMU FW does the + * bus recovery process. Driver should not ignore this BIOS + * advertisement of bus clear feature. + */ + ret = regmap_read(dev->map, DW_IC_CON, &ic_con); + i2c_dw_release_lock(dev); + if (ret) + return ret; + + if (ic_con & DW_IC_CON_BUS_CLEAR_CTRL) + dev->master_cfg |= DW_IC_CON_BUS_CLEAR_CTRL; + ret = dev->init(dev); if (ret) return ret; |