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SubjectRe: [PATCH v3 8/9] clocksource: Add a new timer-ingenic driver
On Wed, Jan 10, 2018 at 4:48 PM, Paul Cercueil <paul@crapouillou.net> wrote:
> This driver will use the TCU (Timer Counter Unit) present on the Ingenic
> JZ47xx SoCs to provide the kernel with a clocksource and timers.
>
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
> drivers/clocksource/Kconfig | 8 ++
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/timer-ingenic.c | 258 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 267 insertions(+)
> create mode 100644 drivers/clocksource/timer-ingenic.c
>
> v2: Use SPDX identifier for the license
> v3: - Move documentation to its own patch
> - Search the devicetree for PWM clients, and use all the TCU
> channels that won't be used for PWM

[...]

> +static int __init ingenic_tcu_init(struct device_node *np)
> +{
> + unsigned long available_channels = GENMASK(NUM_CHANNELS - 1, 0);
> + struct device_node *node;
> + struct ingenic_tcu *tcu;
> + unsigned int i, channel;
> + int err;
> + u32 val;
> +
> + for_each_node_with_property(node, "pwms") {
> + err = of_property_read_u32_index(node, "pwms", 1, &val);

This is the right idea, but a bit fragile. Perhaps its good enough for
your platform, but it would fail if you have another PWM provider like
the gpio-pwm binding or the cell size is not 1 (BTW, I thought the PWM
binding defined 3 cells typically).

Rob

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