On Fri, Jul 30, 2021 at 5:51 PM Sam Protsenko
<semen.protsenko@xxxxxxxxxx> wrote:
>
> For now it's just a stub driver to make serial driver work. Later it
make the serial
> will be implemented properly.
>
> This driver doesn't really change clocks, only registers the UART clock
> as a fixed-rate clock. Without this clock driver the UART driver won't
> work, as it's trying to obtain "uart" clock and fails if it's not able
> to.
> From drivers/tty/serial/samsung_tty.c:
>
> 8<------------------------------------------------------------------->8
> ourport->clk = clk_get(&platdev->dev, "uart");
> if (IS_ERR(ourport->clk)) {
> pr_err("%s: Controller clock not found\n",
> dev_name(&platdev->dev));
> ret = PTR_ERR(ourport->clk);
> goto err;
> }
> 8<------------------------------------------------------------------->8
This is not needed in the commit message.
> In order to get functional serial console we have to implement that
get a functional
> minimal clock driver with "uart" clock. It's not necessary to actually
> configure clocks, as those are already configured in bootloader, so
> kernel can rely on that for now.
> 80 column limit is broken here to make checkpatch happy, otherwise it
> swears about incorrect __initconst usage.
Again, no need to be in the commit message, use the comment field for
this (after the cutter '---' line below).
> Signed-off-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
> ---
> drivers/clk/samsung/Makefile | 1 +
> drivers/clk/samsung/clk-exynos850.c | 63 +++++++++++++++++++++++++++++
> 2 files changed, 64 insertions(+)
> create mode 100644 drivers/clk/samsung/clk-exynos850.c
>
> diff --git a/drivers/clk/samsung/Makefile b/drivers/clk/samsung/Makefile
> index 028b2e27a37e..c46cf11e4d0b 100644
> --- a/drivers/clk/samsung/Makefile
> +++ b/drivers/clk/samsung/Makefile
> @@ -17,6 +17,7 @@ obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK) += clk-exynos5433.o
> obj-$(CONFIG_EXYNOS_AUDSS_CLK_CON) += clk-exynos-audss.o
> obj-$(CONFIG_EXYNOS_CLKOUT) += clk-exynos-clkout.o
> obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK) += clk-exynos7.o
> +obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK) += clk-exynos850.o
> obj-$(CONFIG_S3C2410_COMMON_CLK)+= clk-s3c2410.o
> obj-$(CONFIG_S3C2410_COMMON_DCLK)+= clk-s3c2410-dclk.o
> obj-$(CONFIG_S3C2412_COMMON_CLK)+= clk-s3c2412.o
> diff --git a/drivers/clk/samsung/clk-exynos850.c b/drivers/clk/samsung/clk-exynos850.c
> new file mode 100644
> index 000000000000..3192ec9bb90b
> --- /dev/null
> +++ b/drivers/clk/samsung/clk-exynos850.c
> @@ -0,0 +1,63 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2019 Samsung Electronics Co., Ltd.
> + * Copyright (C) 2021 Linaro Ltd.
> + *
> + * Common Clock Framework support for Exynos850 SoC.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk-provider.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
+ blank line?
> +#include <dt-bindings/clock/exynos850.h>
> +
> +#include "clk.h"
> +
> +/* Fixed rate clocks generated outside the SoC */
> +static struct samsung_fixed_rate_clock exynos850_fixed_rate_ext_clks[] __initdata = {
> + FRATE(OSCCLK, "fin_pll", NULL, 0, 26000000),
> +};
> +
> +/*
> + * Model the UART clock as a fixed-rate clock for now, to make serial driver
> + * work. This clock is already configured in the bootloader.
> + */
> +static const struct samsung_fixed_rate_clock exynos850_peri_clks[] __initconst = {
> + FRATE(DOUT_UART, "DOUT_UART", NULL, 0, 200000000),
> +};
> +
> +static const struct of_device_id ext_clk_match[] __initconst = {
> + { .compatible = "samsung,exynos850-oscclk", .data = (void *)0 },
0 is the default for static variables.
> + {},
No comma needed for the terminator lines.
> +};
> +
> +void __init exynos850_clk_init(struct device_node *np)
> +{
> + void __iomem *reg_base;
> + struct samsung_clk_provider *ctx;
> + if (!np)
> + panic("%s: unable to determine soc\n", __func__);
Check for the sake of additional code?
> + reg_base = of_iomap(np, 0);
This will fail when np == NULL.
> + if (!reg_base)
> + panic("%s: failed to map registers\n", __func__);
> +
> + ctx = samsung_clk_init(np, reg_base, CLK_NR_CLKS);
> + if (!ctx)
> + panic("%s: unable to allocate ctx\n", __func__);
> +
> + samsung_clk_of_register_fixed_ext(ctx,
> + exynos850_fixed_rate_ext_clks,
> + ARRAY_SIZE(exynos850_fixed_rate_ext_clks),
> + ext_clk_match);
> +
> + samsung_clk_register_fixed_rate(ctx, exynos850_peri_clks,
> + ARRAY_SIZE(exynos850_peri_clks));
> +
> + samsung_clk_of_add_provider(np, ctx);
> +}
> +
> +CLK_OF_DECLARE(exynos850_clk, "samsung,exynos850-clock", exynos850_clk_init);
--
With Best Regards,
Andy Shevchenko
