On 8/2/2022 5:07 PM, William Zhang wrote:
Hi Rafal,
On 08/01/2022 10:26 PM, Rafał Miłecki wrote:
On 2.08.2022 00:03, William Zhang wrote:
This driver supports the peripheral block timer found on the Broadcom
BCA SoCs. It is 30-bit up-count timer running at 50MHz and can be used
as the system clock source such as on BCM63138.
Signed-off-by: William Zhang <william.zh...@broadcom.com>
(...)
+static const struct udevice_id bcmbca_timer_ids[] = {
+ { .compatible = "brcm,bcm-timers" },
+ { }
+};
+
+U_BOOT_DRIVER(bcmbca_timer) = {
+ .name = "bcmbca_timer",
+ .id = UCLASS_TIMER,
+ .of_match = bcmbca_timer_ids,
+ .priv_auto = sizeof(struct bcmbca_timer_priv),
+ .probe = bcmbca_timer_probe,
+ .ops = &bcmbca_timer_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};
That "brcm,bcm-timers" seems like a really wide bidding. Is that exact
timer block guaranteed to be present on all Broadcom devices? Does it
exist e.g. on Northstar SoCs? Or old MIPS SoCs like BCM4706?
Agree I will make change to use brcm,bcmbca-timers.
Why not change to use a compatible string that uses the first chip in
which this timer block was introduced, was that 6345 or later?
It seems that even across BCMBCA devices this block may differ and may
need different bindings. Most SoCs have 4 CTL and 4 CNT registers but
some have only 3 + 3 (BCM6838 BCM60333 BCM63268).
This timer driver is intended for the clock source for u-boot only so
only need the first channel. Although it could work for the old mips
based dsl chip, BCMBCA chip family support is only for the new ARM based
chips which is stated in the BCMBA introduction patch.
Finally could we have that binding actually documented?
I don't see u-boot has binding document. I believe it generally use
linux binding document. I have no plan to upstream this driver to
linux. But I can put the binding info in the driver if that is the right
way to do in u-boot.
Out of curiosity, why does u-boot require this timer as opposed to using
the Cortex-A9 architected timers? Is it necessary to boot strap the A9
timers?
--
Florian
