Re: [PATCH 3/3] clk: meson: add sub EMMC clock controller driver

[Martin Blumenstingl <martin.blumenstingl@googlemail.com>]

Hi Yixun,

apart from what Jerome found this looks good to me.
one small "issue" and a question are inline below

On Tue, Jul 3, 2018 at 9:00 AM Yixun Lan <yixun.lan@amlogic.com> wrote:
>
> This patch will add a EMMC clock controller driver support,
> It provide a mux and divider clock.
>
> This clock driver can be protentially used by either EMMC and
> NAND driver.
>
> Signed-off-by: Yixun Lan <yixun.lan@amlogic.com>
> ---
>  drivers/clk/meson/Kconfig     |   9 +++
>  drivers/clk/meson/Makefile    |   1 +
>  drivers/clk/meson/emmc-clkc.c | 136 ++++++++++++++++++++++++++++++++++
>  3 files changed, 146 insertions(+)
>  create mode 100644 drivers/clk/meson/emmc-clkc.c
>
> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
> index efaa70f682b4..2f27ff08e4eb 100644
> --- a/drivers/clk/meson/Kconfig
> +++ b/drivers/clk/meson/Kconfig
> @@ -15,6 +15,15 @@ config COMMON_CLK_MESON_AO
>         select COMMON_CLK_REGMAP_MESON
>         select RESET_CONTROLLER
>
> +config COMMON_CLK_EMMC_MESON
> +       tristate "Meson EMMC Sub Clock Controller Driver"
> +       depends on COMMON_CLK_AMLOGIC
> +       select MFD_SYSCON
> +       select REGMAP
> +       help
> +         Support for the EMMC sub clock controller on AmLogic Meson Platform,
> +         Say Y if you want this clock enabled.
> +
>  config COMMON_CLK_REGMAP_MESON
>         bool
>         select REGMAP
> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
> index 72ec8c40d848..2f04f77ba4de 100644
> --- a/drivers/clk/meson/Makefile
> +++ b/drivers/clk/meson/Makefile
> @@ -9,4 +9,5 @@ obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
>  obj-$(CONFIG_COMMON_CLK_GXBB)   += gxbb.o gxbb-aoclk.o gxbb-aoclk-32k.o
>  obj-$(CONFIG_COMMON_CLK_AXG)    += axg.o axg-aoclk.o
>  obj-$(CONFIG_COMMON_CLK_AXG_AUDIO)     += axg-audio.o
> +obj-$(CONFIG_COMMON_CLK_EMMC_MESON)    += emmc-clkc.o
>  obj-$(CONFIG_COMMON_CLK_REGMAP_MESON)  += clk-regmap.o
> diff --git a/drivers/clk/meson/emmc-clkc.c b/drivers/clk/meson/emmc-clkc.c
> new file mode 100644
> index 000000000000..cf5bb9f34327
> --- /dev/null
> +++ b/drivers/clk/meson/emmc-clkc.c
> @@ -0,0 +1,136 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Amlogic Meson EMMC Sub Clock Controller Driver
> + *
> + * Copyright (c) 2018 Amlogic, inc.
> + * Author: Yixun Lan <yixun.lan@amlogic.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/init.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include <dt-bindings/clock/emmc-clkc.h>
> +
> +#include "clkc.h"
> +
> +#define SD_EMMC_CLOCK          0
> +#define MUX_CLK_NUM_PARENTS    2
> +#define EMMC_MAX_CLKS          2
> +#define CLK_NAME_LEN           48
> +
> +static struct clk_regmap_mux_data emmc_clkc_mux_data = {
> +       .offset = SD_EMMC_CLOCK,
> +       .mask = 0x3,
> +       .shift = 6,
> +};
> +
> +static struct clk_regmap_div_data emmc_clkc_div_data = {
> +       .offset = SD_EMMC_CLOCK,
> +       .shift = 0,
> +       .width = 6,
> +       .flags = CLK_DIVIDER_ROUND_CLOSEST | CLK_DIVIDER_ONE_BASED,
> +};
> +
> +static const struct of_device_id clkc_match_table[] = {
> +       { .compatible = "amlogic,emmc-clkc" },
shouldn't this be "amlogic,meson-axg-emmc-clkc" (and optionally also
"amlogic,meson-gx-emmc-clkc")?

> +       {}
> +};
> +
> +static int emmc_clkc_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct clk_regmap *mux, *div;
> +       struct regmap *map;
> +       struct clk *clk;
> +       int i, ret;
> +       const char *parent_names[MUX_CLK_NUM_PARENTS];
> +       struct clk_init_data init;
> +       char mux_name[CLK_NAME_LEN], div_name[CLK_NAME_LEN];
> +       struct clk_hw_onecell_data *onecell_data;
> +
> +       map = syscon_node_to_regmap(dev->of_node);
> +
> +       mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
> +       div = devm_kzalloc(dev, sizeof(*div), GFP_KERNEL);
> +
> +       onecell_data = devm_kzalloc(dev, sizeof(*onecell_data) +
> +                                   sizeof(*onecell_data->hws) * EMMC_MAX_CLKS,
> +                                   GFP_KERNEL);
> +
> +       if (!mux || !div || !onecell_data)
> +               return -ENOMEM;
> +
> +       for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
> +               char name[8];
> +
> +               snprintf(name, sizeof(name), "clkin%d", i);
> +               clk = devm_clk_get(dev, name);
> +               if (IS_ERR(clk)) {
> +                       if (clk != ERR_PTR(-EPROBE_DEFER))
> +                               dev_err(dev, "Missing clock %s\n", name);
> +                       return PTR_ERR(clk);
> +               }
> +
> +               parent_names[i] = __clk_get_name(clk);
> +       }
> +
> +       mux->map = map;
> +       mux->data = &emmc_clkc_mux_data;
> +
> +       snprintf(mux_name, CLK_NAME_LEN, "%s#emmc_mux", dev_name(dev));
> +
> +       init.name = mux_name;
> +       init.ops = &clk_regmap_mux_ops;
> +       init.flags = CLK_SET_RATE_PARENT;
> +       init.parent_names = parent_names;
> +       init.num_parents = MUX_CLK_NUM_PARENTS;
> +
> +       mux->hw.init = &init;
> +       ret = devm_clk_hw_register(dev, &mux->hw);
> +       if (ret) {
> +               dev_err(dev, "Mux clock registration failed\n");
> +               return ret;
> +       }
> +
> +       parent_names[0] = mux_name;
> +       div->map = map;
> +       div->data = &emmc_clkc_div_data;
> +
> +       snprintf(div_name, CLK_NAME_LEN, "%s#emmc_div", dev_name(dev));
> +
> +       init.name = div_name;
> +       init.ops = &clk_regmap_divider_ops;
> +       init.flags = CLK_SET_RATE_PARENT;
> +       init.parent_names = parent_names;
> +       init.num_parents = 1;
> +
> +       div->hw.init = &init;
> +       ret = devm_clk_hw_register(dev, &div->hw);
> +       if (ret) {
> +               dev_err(dev, "Div clock registration failed\n");
> +               return ret;
> +       }
> +
> +       onecell_data->hws[CLKID_EMMC_C_MUX] = &mux->hw,
> +       onecell_data->hws[CLKID_EMMC_C_DIV] = &div->hw,
> +       onecell_data->num = EMMC_MAX_CLKS;
you are describing the mux and the divider here
however, meson-gx-mmc.c has a few more clock related bits:
- CLK_CORE_PHASE_MASK
- CLK_TX_PHASE_MASK
- CLK_RX_PHASE_MASK
- CLK_V2_TX_DELAY_MASK / CLK_V3_TX_DELAY_MASK
- CLK_V2_RX_DELAY_MASK / CLK_V3_RX_DELAY_MASK
- CLK_V2_ALWAYS_ON / CLK_V3_ALWAYS_ON

are these used for the MMC clock or are some of these routed to the
NAND pins as well?


Regards
Martin