RE: [PATCH 2/2] drivers: misc: add ripple counter driver

Chen, Mike Ximing
2021-02-28T05:48:06Z

> -----Original Message-----
> From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> Sent: Friday, February 26, 2021 9:14 AM
> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Rob Herring
> <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Arnd Bergmann
> <arnd@arndb.de>; linux-clk@vger.kernel.org; Rasmus Villemoes
> <linux@rasmusvillemoes.dk>
> Subject: [PATCH 2/2] drivers: misc: add ripple counter driver
>
> The only purpose of this driver is to serve as a consumer of the input
> clock, to prevent it from being disabled by clk_disable_unused().
>
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> ---
> drivers/misc/Kconfig | 7 +++++++
> drivers/misc/Makefile | 1 +
> drivers/misc/ripple-ctr.c | 31 +++++++++++++++++++++++++++++++
> 3 files changed, 39 insertions(+)
> create mode 100644 drivers/misc/ripple-ctr.c
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index f532c59bb59b..44b0b6ce42df 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -445,6 +445,13 @@ config HISI_HIKEY_USB
> switching between the dual-role USB-C port and the USB-A host ports
> using only one USB controller.
>
> +config RIPPLE_CTR
> + tristate "Trivial ripple counter driver"
> + help
> + This provides a stub driver for a ripple counter, whose
> + only purpose is to request and enable the clock source
> + driving the counter.
> +
> source "drivers/misc/c2port/Kconfig"
> source "drivers/misc/eeprom/Kconfig"
> source "drivers/misc/cb710/Kconfig"
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 99b6f15a3c70..d560163068a9 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -56,3 +56,4 @@ obj-$(CONFIG_HABANA_AI) += habanalabs/
> obj-$(CONFIG_UACCE) += uacce/
> obj-$(CONFIG_XILINX_SDFEC) += xilinx_sdfec.o
> obj-$(CONFIG_HISI_HIKEY_USB) += hisi_hikey_usb.o
> +obj-$(CONFIG_RIPPLE_CTR) += ripple-ctr.o
> diff --git a/drivers/misc/ripple-ctr.c b/drivers/misc/ripple-ctr.c
> new file mode 100644
> index 000000000000..f086eaf335df
> --- /dev/null
> +++ b/drivers/misc/ripple-ctr.c
> @@ -0,0 +1,31 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +static int ripple_ctr_probe(struct platform_device *pdev)
> +{
> + struct clk *clk;
> +
> + clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> + return clk_prepare_enable(clk);
> +}
> +
> +static const struct of_device_id ripple_ctr_ids[] = {
> + { .compatible = "linux,ripple-counter", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, ripple_ctr_ids);
> +
> +static struct platform_driver ripple_ctr_driver = {
> + .driver = {
> + .name = "ripple-counter",
> + .of_match_table = ripple_ctr_ids,
> + },
> + .probe = ripple_ctr_probe,
> +};
> +module_platform_driver(ripple_ctr_driver);

Missing MODULE_LICENSE() tag?
See https://www.kernel.org/doc/html/latest/process/license-rules.html#license-identifiers

> --
> 2.29.2