Re: [PATCH v2 5/6] clocksource: kvx: Add kvx clocksource support

[Sascha Hauer <s.hauer@pengutronix.de>]

On Sat, Apr 04, 2020 at 10:29:09PM +0200, Clement Leger wrote:
> Add a clocksource for kvx architecture based on core performance
> counter. This performance counter is configured to count cycles and as
> such can be used to be a clocksource.
> 
> Signed-off-by: Clement Leger <cleger@kalray.eu>
> ---
>  arch/kvx/configs/generic_defconfig |  1 +
>  drivers/clocksource/Kconfig        |  4 ++
>  drivers/clocksource/Makefile       |  1 +
>  drivers/clocksource/kvx_timer.c    | 59 ++++++++++++++++++++++++++++++
>  4 files changed, 65 insertions(+)
>  create mode 100644 drivers/clocksource/kvx_timer.c
> 
> diff --git a/arch/kvx/configs/generic_defconfig b/arch/kvx/configs/generic_defconfig
> index 3f7bb0f19..d0c2252bf 100644
> --- a/arch/kvx/configs/generic_defconfig
> +++ b/arch/kvx/configs/generic_defconfig
> @@ -1,6 +1,7 @@
>  CONFIG_AUTO_COMPLETE=y
>  CONFIG_BAUDRATE=115200
>  # CONFIG_BOOTM is not set
> +CONFIG_CLOCKSOURCE_KVX=y
>  CONFIG_CMD_CMP=y
>  CONFIG_CMD_OF_DUMP=y
>  CONFIG_CMD_POWEROFF=y
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index 39ddd159f..8805cda39 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -47,6 +47,10 @@ config CLOCKSOURCE_EFI_X86
>  	bool "EFI X86 HW driver"
>  	depends on EFI_BOOTUP && X86
>  
> +config CLOCKSOURCE_KVX
> +	bool "KVX core timer clocksource"
> +	depends on KVX
> +
>  config CLOCKSOURCE_MVEBU
>  	bool
>  	depends on ARCH_MVEBU
> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index cba6344bb..b4607f787 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_CLOCKSOURCE_CLPS711X) += clps711x.o
>  obj-$(CONFIG_CLOCKSOURCE_DIGIC)   += digic.o
>  obj-$(CONFIG_CLOCKSOURCE_EFI) += efi.o
>  obj-$(CONFIG_CLOCKSOURCE_EFI_X86) += efi_x86.o
> +obj-$(CONFIG_CLOCKSOURCE_KVX)     += kvx_timer.o
>  obj-$(CONFIG_CLOCKSOURCE_MVEBU)   += mvebu.o
>  obj-$(CONFIG_CLOCKSOURCE_NOMADIK) += nomadik.o
>  obj-$(CONFIG_CLOCKSOURCE_ORION)   += orion.o
> diff --git a/drivers/clocksource/kvx_timer.c b/drivers/clocksource/kvx_timer.c
> new file mode 100644
> index 000000000..be2545ed0
> --- /dev/null
> +++ b/drivers/clocksource/kvx_timer.c
> @@ -0,0 +1,59 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2018 Kalray Inc.
> + */
> +
> +#include <common.h>
> +#include <clock.h>
> +#include <init.h>
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +
> +#include <asm/sfr.h>
> +
> +static uint64_t kvx_pm_read(void)
> +{
> +	return kvx_sfr_get(PM0);
> +}
> +
> +static struct clocksource kvx_clksrc = {
> +	.read	= kvx_pm_read,
> +	.mask	= CLOCKSOURCE_MASK(64),
> +	.shift	= 0,
> +};
> +
> +static int kvx_timer_probe(struct device_d *dev)
> +{
> +	struct clk *clk;
> +	uint32_t clk_freq;
> +	struct device_node *np = dev->device_node;
> +
> +	/* Get clock frequency */
> +	clk = of_clk_get(np, 0);
> +	if (IS_ERR(clk)) {
> +		pr_err("Failed to get CPU clock: %ld\n", PTR_ERR(clk));
> +		return PTR_ERR(clk);
> +	}

You have a struct device_d pointer, in that case you should use clk_get
rather than of_clk_get and dev_err rather than pr_err.

> +
> +	clk_freq = clk_get_rate(clk);
> +	clk_put(clk);

clk_put looks wrong here. Better just keep the ownership of the clock,
although it doesn't make much difference here of course.

Sascha

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