Currently the I3C framework limits SCL frequency to FM speed when dealing with a mixed slow bus, even if all I2C devices are FM+ capable.
The core was also not accounting for I3C speed limitations when operating in mixed slow mode and was erroneously using FM+ speed as the max I2C speed when operating in mixed fast mode.
Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure") Signed-off-by: Vitor Soares vitor.soares@synopsys.com Cc: Boris Brezillon bbrezillon@kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- Changes in v3: Change dev_warn() to dev_dbg()
Changes in v2: Enhance commit message Add dev_warn() in case user-defined i2c rate doesn't match LVR constraint Add dev_warn() in case user-defined i3c rate lower than i2c rate
drivers/i3c/master.c | 61 +++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 48 insertions(+), 13 deletions(-)
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c index 5f4bd52..f8e580e 100644 --- a/drivers/i3c/master.c +++ b/drivers/i3c/master.c @@ -91,6 +91,12 @@ void i3c_bus_normaluse_unlock(struct i3c_bus *bus) up_read(&bus->lock); }
+static struct i3c_master_controller * +i3c_bus_to_i3c_master(struct i3c_bus *i3cbus) +{ + return container_of(i3cbus, struct i3c_master_controller, bus); +} + static struct i3c_master_controller *dev_to_i3cmaster(struct device *dev) { return container_of(dev, struct i3c_master_controller, dev); @@ -565,20 +571,48 @@ static const struct device_type i3c_masterdev_type = { .groups = i3c_masterdev_groups, };
-int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode) +int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode, + unsigned long max_i2c_scl_rate) { - i3cbus->mode = mode;
- if (!i3cbus->scl_rate.i3c) - i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE; + struct i3c_master_controller *master = i3c_bus_to_i3c_master(i3cbus);
- if (!i3cbus->scl_rate.i2c) { - if (i3cbus->mode == I3C_BUS_MODE_MIXED_SLOW) - i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE; - else - i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_PLUS_SCL_RATE; + i3cbus->mode = mode; + + switch (i3cbus->mode) { + case I3C_BUS_MODE_PURE: + if (!i3cbus->scl_rate.i3c) + i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE; + break; + case I3C_BUS_MODE_MIXED_FAST: + if (!i3cbus->scl_rate.i3c) + i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE; + if (!i3cbus->scl_rate.i2c) + i3cbus->scl_rate.i2c = max_i2c_scl_rate; + break; + case I3C_BUS_MODE_MIXED_SLOW: + if (!i3cbus->scl_rate.i2c) + i3cbus->scl_rate.i2c = max_i2c_scl_rate; + if (!i3cbus->scl_rate.i3c || + i3cbus->scl_rate.i3c > i3cbus->scl_rate.i2c) + i3cbus->scl_rate.i3c = i3cbus->scl_rate.i2c; + break; + default: + return -EINVAL; }
+ if (i3cbus->scl_rate.i3c < i3cbus->scl_rate.i2c) + dev_dbg(&master->dev, + "i3c-scl-hz=%ld lower than i2c-scl-hz=%ld\n", + i3cbus->scl_rate.i3c, i3cbus->scl_rate.i2c); + + if (i3cbus->scl_rate.i2c != I3C_BUS_I2C_FM_SCL_RATE && + i3cbus->scl_rate.i2c != I3C_BUS_I2C_FM_PLUS_SCL_RATE && + i3cbus->mode != I3C_BUS_MODE_PURE) + dev_dbg(&master->dev, + "i2c-scl-hz=%ld not defined according MIPI I3C spec\n", + i3cbus->scl_rate.i2c); + /* * I3C/I2C frequency may have been overridden, check that user-provided * values are not exceeding max possible frequency. @@ -1966,9 +2000,6 @@ of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master, /* LVR is encoded in reg[2]. */ boardinfo->lvr = reg[2];
- if (boardinfo->lvr & I3C_LVR_I2C_FM_MODE) - master->bus.scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE; - list_add_tail(&boardinfo->node, &master->boardinfo.i2c); of_node_get(node);
@@ -2417,6 +2448,7 @@ int i3c_master_register(struct i3c_master_controller *master, const struct i3c_master_controller_ops *ops, bool secondary) { + unsigned long i2c_scl_rate = I3C_BUS_I2C_FM_PLUS_SCL_RATE; struct i3c_bus *i3cbus = i3c_master_get_bus(master); enum i3c_bus_mode mode = I3C_BUS_MODE_PURE; struct i2c_dev_boardinfo *i2cbi; @@ -2466,9 +2498,12 @@ int i3c_master_register(struct i3c_master_controller *master, ret = -EINVAL; goto err_put_dev; } + + if (i2cbi->lvr & I3C_LVR_I2C_FM_MODE) + i2c_scl_rate = I3C_BUS_I2C_FM_SCL_RATE; }
- ret = i3c_bus_set_mode(i3cbus, mode); + ret = i3c_bus_set_mode(i3cbus, mode, i2c_scl_rate); if (ret) goto err_put_dev;