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

Jerome Brunet
2018-07-03T08:51:22Z

On Tue, 2018-07-03 at 14:57 +0000, Yixun Lan 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,
I thought you were not writing amlogic this way anymore -^ ?? ^
... or be consistent about it. |
|
Drop the camel case please -------------|
> + 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>

replace with linux/module.h

> +#include <linux/of_address.h>

Why do you need this ?

> +#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,

If you round the divider "closest", shouldn't you do the same for the mux ?

> +};
> +
> +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" },
> + {}
> +};
> +
> +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];

I'm not big fan, especially if you append the dev_name() to the clock name.

> + 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));

I'd prefer if you used kasprintf() and free the name after the name after
registration.

> +
> + init.name = mux_name;
> + init.ops = &clk_regmap_mux_ops;
> + init.flags = CLK_SET_RATE_PARENT;

If you really intend to have manual control over the mux, as commented in patch
2, you need CLK_SET_RATE_NOREPARENT here, otherwise whatever you set may be
overwritten by the next clk_set_rate() call. Please choose.

> + 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");

s/Div/Divider

> + 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;
> +
> + return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
> + onecell_data);

This is a long function with a lot of locals. please break that up.
(for example, one function to register each clock, helper to allocate the clk_hw
and names ...)

> +}
> +
> +static struct platform_driver emmc_clkc_driver = {
> + .probe = emmc_clkc_probe,
> + .driver = {
> + .name = "emmc-clkc",
> + .of_match_table = clkc_match_table,
> + },
> +};
> +

It should be a module, not a builtin - especially when the configuration is a
tristate

> +builtin_platform_driver(emmc_clkc_driver);