On 09/12/2016 07:54 PM, Wenyou Yang wrote:
For the peripheral clock, provide the clock ops for the clock
provider, such as spi0_clk. The .of_xlate is to get the clk->id,
the .enable is to enable the spi0 peripheral clock, the .get_rate
is to get the clock frequency.
The driver for periph32ck node is responsible for recursively
binding its children as clk devices, not provide the clock ops.
So do the generated clock and system clock.
diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
+/**
+ * generated_clk_bind() - for the generated clock driver
+ * Recursively bind its children as clk devices.
+ *
+ * @return: 0 on success, or negative error code on failure
+ */
+static int generated_clk_bind(struct udevice *dev)
... (code to enumerate/instantiate all child DT nodes)
+}
+
+static const struct udevice_id generated_clk_match[] = {
+ { .compatible = "atmel,sama5d2-clk-generated" },
+ {}
+};
+
+U_BOOT_DRIVER(generated_clk) = {
+ .name = "generated-clk",
+ .id = UCLASS_CLK,
+ .of_match = generated_clk_match,
+ .bind = generated_clk_bind,
+};
This driver shouldn't be UCLASS_CLK, and can't be without any clock ops
implemented. It appears to be for another DT node that solely exists to
house various sub-nodes which are the actual clock providers. I believe
you should make this UCLASS_MISC. I guess you need to keep the custom
bind function, since all the child nodes that it enumerates explicitly
don't have a compatible value, so you can't rely on e.g. the default
UCLASS_SIMPLE_BUS bind function to enumerate them.
BTW, while reading ./arch/arm/dts/sama5d2.dtsi, I noticed:
sdmmc0_gclk: sdmmc0_gclk {
#clock-cells = <0>;
reg = <31>;
};
Doesn't dtc complain about that? The node has a reg property, yet there
is no unit address in the node name to match it. Instead, that node
should be:
sdmmc0_gclk: sdmmc0_gclk@31 {
#clock-cells = <0>;
reg = <31>;
};
+static int generic_clk_of_xlate(struct clk *clk,
+ struct fdtdec_phandle_args *args)
{
- struct pmc_platdata *plat = dev_get_platdata(clk->dev);
+ int periph;
The following should likely be added here:
if (args->args_count) {
debug("Invaild args_count: %d\n", args->args_count);
return -EINVAL;
}
+ periph = fdtdec_get_uint(gd->fdt_blob, clk->dev->of_offset, "reg", -1);
+ if (periph < 0)
+ return -EINVAL;
+
+ clk->id = periph;
I guess that's OK. of_xlate is really intended to parse/process the
clocks property in the client DT node. However, I suppose parsing the
referenced DT node is probably OK too. Has this Atmel clock binding, and
a similar clock driver implementation (including custom of_xlate) been
reviewed for inclusion in the Linux kernel? I'd be curious if the same
technique was/wasn't allowed there.
+static int generic_clk_probe(struct udevice *dev)
...
+ dev = dev_get_parent(dev);
+ dev = dev_get_parent(dev);
That line is duplicated.
diff --git a/drivers/clk/at91/clk-peripheral.c
b/drivers/clk/at91/clk-peripheral.c
The same comments as above all apply to this file too.
+static ulong periph_get_rate(struct clk *clk)
{
+ struct udevice *dev;
+ struct clk clk_dev;
+ int ret;
+ dev = dev_get_parent(clk->dev);
+ ret = clk_request(dev, &clk_dev);
You haven't filled in clk_dev.id here. That needs to be filled in before
calling clk_request().
+ if (ret)
+ return ret;
+
+ ret = clk_get_by_index(dev, 0, &clk_dev);
This over-writes everything in clk_dev, thus making the call to
clk_request() above pointless.
+ if (ret)
+ return ret;
+
+ return clk_get_rate(&clk_dev);
You need to call clk_free(&clk_dev) before returning. This comment
applies to generated_clk_get_rate()/generic_clk_get_rate() too (in the
previous file), although that problem existed before this patch.
+static int periph_clk_probe(struct udevice *dev)
+{
+ struct periph_clk_platdata *plat = dev_get_platdata(dev);
+
+ dev = dev_get_parent(dev);
+ dev = dev_get_parent(dev);
+ plat->reg_base = (struct at91_pmc *)dev_get_addr_ptr(dev);
It would be helpful documentation-wise to use separate variables for
those parents; make the variable name indicate what the parent is
expected to be:
dev_periph_container = dev_get_parent(dev);
dev_pmc = dev_get_parent(dev_periph_container);
diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
Likewise, all the same comments above apply to this file too.
+/**
+ * at91_system_clk_bind() - for the system clock driver
+ * Recursively bind its children as clk devices.
+ *
+ * @return: 0 on success, or negative error code on failure
+ */
+static int at91_system_clk_bind(struct udevice *dev)
+{
...
+ /*
+ * If this node has "compatible" property, this is not
+ * a pin configuration node, but a normal device. skip.
+ */
This is nothing to do with pin configuration, but clocks.
This function is duplicated at least 3 times in this patch. It might be
useful to implement it in some common location, and just call it from
all the different clock drivers. You'd need to pass in a string for the
driver name to bind to, but that's the only difference I see.
I wouldn't be surprised if other parts of the Atmel clock drivers could
be shared too; of_xlate is probably common, and perhaps get_rate for
some clocks that are derived from parent clocks. Still, cleaning that up
might be a job for a separate series.
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