On Mon, 22 Apr 2019 15:54:33 +0000 Vitor Soares Vitor.Soares@synopsys.com wrote:
{ i3cbus->mode = mode;
- if (!i3cbus->scl_rate.i3c)
i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;- if (!i3cbus->scl_rate.i2c) {
if (i3cbus->mode == I3C_BUS_MODE_MIXED_SLOW)i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE;elsei3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_PLUS_SCL_RATE;
- 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 = i2c_scl_rate;break;- case I3C_BUS_MODE_MIXED_SLOW:
if (!i3cbus->scl_rate.i2c)i3cbus->scl_rate.i2c = i2c_scl_rate;i3cbus->scl_rate.i3c = i3cbus->scl_rate.i2c;Maybe we should do
if (!i3cbus->scl_rate.i3c || i3cbus->scl_rate.i3c > i3cbus->scl_rate.i2c) i3cbus->scl_rate.i3c = i3cbus->scl_rate.i2c;Just in case the I3C rate forced by the user is lower than the max I2C rate.
That was something that I considered but TBH it isn't a real use case.
Add a WARN_ON() to at least catch such inconsistencies. And maybe we should add a dev_warn() when the user-defined rates do not match the mode/LVR constraints. It's easy to do a mistake when writing a dts.
I think the WARN_ON() is too evasive on the screen and won't provide the information we want. The dev_warn() should work perfectly here.
if (i3cbus->scl_rate.i3c < i3cbus->scl_rate.i2c) dev_warn(&i3cbus->cur_master->dev->dev, "%s: i3c-scl-hz lower then i2c-scl-hz\n", __func__);
Using dev_warn() sounds good, though I don't think you need the __func__ here. Also, please print the i2c/i3c rates in the message, and align the second line on the open parens.
if (i3cbus->scl_rate.i2c != I3C_BUS_I2C_FM_SCL_RATE || i3cbus->scl_rate.i2c != I3C_BUS_I2C_FM_PLUS_SCL_RATE) dev_warn(&i3cbus->cur_master->dev->dev, "%s: i2c-scl-hz not defined according MIPI I3C spec\n", __func__);
Is that really a problem? Having an i2c rate that is less than FM speed sounds like a valid case to me.
Maybe it make more sense to do this check on of_populate_i3c_bus(), what do you think?
No, we really want to have this check here, because we might support other HW description formats at some point (board-files, ACPI, ...).