On 4/16/24 16:20, Guenter Roeck wrote:
On Tue, Apr 16, 2024 at 01:09:04PM -0500, Eddie James wrote:
On 4/15/24 17:11, Andi Shyti wrote:
Hi Eddie,
@@ -689,6 +692,20 @@ static int fsi_i2c_probe(struct device *dev)
mutex_init(&i2c->lock);
i2c->fsi = to_fsi_dev(dev);
INIT_LIST_HEAD(&i2c->ports);
+ i2c->clock_div = I2C_DEFAULT_CLK_DIV;
+
+ lbus = fsi_device_local_bus_frequency(i2c->fsi);
+ if (lbus) {
+ u32 clock = I2C_DEFAULT_CLK_RATE;
I don't see the need for initialization.
Does device_property_read_u32 set clock if the property isn't found? If not,
it needs to be initialized here. Or I can set it in an else statement from
device_property_read_u32.
+
+ if (!device_property_read_u32(dev, "clock-frequency", &clock)) {
+ if (!clock)
+ clock = I2C_DEFAULT_CLK_RATE;
+ }
if (device_property_read_u32(dev, "clock-frequency", &clock) || !clock)
clock = I2C_DEFAULT_CLK_RATE;
Nice one, thanks.
+
+ // i2c clock rate = local bus clock / (4 * (i2c clock div + 1))
You forgot to remove this.
I actually meant to leave that comment to explain how the clock rate is
calculated, as the reverse calculation in the code is a little more
confusing.
Partially that is because you implemented DIV_ROUND_UP() manually.
Thanks Guenter, good point.
Eddie
Andi
+ i2c->clock_div = (((lbus + (clock - 1)) / clock) / 4) - 1;
= DIV_ROUND_UP(lbus, clock) / 4 - 1
Guenter
