linux-kernel - Re: [PATCH V3 5/8] clk: qcom: Add ipq apss clock controller

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Date:   Wed, 22 Apr 2020 02:04:22 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Sivaprakash Murugesan <sivaprak@...eaurora.org>, agross@...nel.org,
        bjorn.andersson@...aro.org, devicetree@...r.kernel.org,
        jassisinghbrar@...il.com, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        mturquette@...libre.com, robh+dt@...nel.org
Cc:     Sivaprakash Murugesan <sivaprak@...eaurora.org>
Subject: Re: [PATCH V3 5/8] clk: qcom: Add ipq apss clock controller

Quoting Sivaprakash Murugesan (2020-04-13 19:55:19)
> The CPU on Qualcomm's IPQ platform devices are clocked primarily by a
> PLL and xo which are connected to a mux and enable block, This patch adds

The comma should be a period? Don't write "This patch" in commit text.

> support for the mux and the enable.
> 
> Signed-off-by: Sivaprakash Murugesan <sivaprak@...eaurora.org>
> ---
>  drivers/clk/qcom/Kconfig    |  10 +++++
>  drivers/clk/qcom/Makefile   |   1 +
>  drivers/clk/qcom/apss-ipq.c | 107 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 118 insertions(+)
>  create mode 100644 drivers/clk/qcom/apss-ipq.c
> 
> diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
> index 15cdcdc..8573f2e 100644
> --- a/drivers/clk/qcom/Kconfig
> +++ b/drivers/clk/qcom/Kconfig
> @@ -89,6 +89,16 @@ config APQ_MMCC_8084
>           Say Y if you want to support multimedia devices such as display,
>           graphics, video encode/decode, camera, etc.
>  
> +config IPQ_APSS
> +       tristate "IPQ APSS Clock Controller"
> +       default N

Drop this, it's already the default.

> +       help
> +         Support for APSS clock controller on ipq platform devices. The

Maybe say "IPQ platforms" and drop the devices part?

> +         APSS clock controller manages the Mux and enable block that feeds the
> +         CPUs.
> +         Say Y if you want to support CPU frequency scaling on
> +         ipq based devices.
> +
>  config IPQ_GCC_4019
>         tristate "IPQ4019 Global Clock Controller"
>         help
> diff --git a/drivers/clk/qcom/apss-ipq.c b/drivers/clk/qcom/apss-ipq.c
> new file mode 100644
> index 0000000..a37cd98
> --- /dev/null
> +++ b/drivers/clk/qcom/apss-ipq.c
> @@ -0,0 +1,107 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/err.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk-provider.h>
> +#include <linux/regmap.h>
> +#include <linux/module.h>
> +
> +#include <dt-bindings/clock/qcom,apss-ipq.h>
> +
> +#include "common.h"
> +#include "clk-regmap.h"
> +#include "clk-branch.h"
> +#include "clk-alpha-pll.h"
> +#include "clk-regmap-mux.h"
> +
> +enum {
> +       P_XO,
> +       P_APSS_PLL_EARLY,
> +};
> +
> +static const struct clk_parent_data parents_apcs_alias0_clk_src[] = {
> +       { .fw_name = "xo" },
> +       { .fw_name = "pll" },
> +};
> +
> +static const struct parent_map parents_apcs_alias0_clk_src_map[] = {
> +       { P_XO, 0 },
> +       { P_APSS_PLL_EARLY, 5 },
> +};
> +
> +static struct clk_regmap_mux apcs_alias0_clk_src = {
> +       .reg = 0x0050,
> +       .width = 3,
> +       .shift = 7,
> +       .parent_map = parents_apcs_alias0_clk_src_map,
> +       .clkr.hw.init = &(struct clk_init_data){
> +               .name = "apcs_alias0_clk_src",
> +               .parent_data = parents_apcs_alias0_clk_src,
> +               .num_parents = 2,
> +               .ops = &clk_regmap_mux_closest_ops,
> +               .flags = CLK_SET_RATE_PARENT,
> +       },
> +};
> +
> +/*required for cpufreq*/

This comment doesn't help in understanding.

> +static struct clk_branch apcs_alias0_core_clk = {
> +       .halt_reg = 0x0058,
> +       .clkr = {
> +               .enable_reg = 0x0058,
> +               .enable_mask = BIT(0),
> +               .hw.init = &(struct clk_init_data){
> +                       .name = "apcs_alias0_core_clk",
> +                       .parent_hws = (const struct clk_hw *[]){
> +                               &apcs_alias0_clk_src.clkr.hw },
> +                       .num_parents = 1,
> +                       .flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,

Please comment why the clk is critical.

> +                       .ops = &clk_branch2_ops,
> +               },
> +       },
> +};
> +
> +static const struct regmap_config apss_ipq_regmap_config = {
> +       .reg_bits       = 32,
> +       .reg_stride     = 4,
> +       .val_bits       = 32,
> +       .max_register   = 0x1000,
> +       .fast_io        = true,
> +};
> +
> +static struct clk_regmap *apss_ipq_clks[] = {
> +       [APCS_ALIAS0_CLK_SRC] = &apcs_alias0_clk_src.clkr,
> +       [APCS_ALIAS0_CORE_CLK] = &apcs_alias0_core_clk.clkr,
> +};
> +
> +static const struct qcom_cc_desc apss_ipq_desc = {
> +       .config = &apss_ipq_regmap_config,
> +       .clks = apss_ipq_clks,
> +       .num_clks = ARRAY_SIZE(apss_ipq_clks),
> +};
> +
> +static int apss_ipq_probe(struct platform_device *pdev)
> +{
> +       struct regmap *regmap;
> +
> +       regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +       if (IS_ERR(regmap))
> +               return PTR_ERR(regmap);
> +
> +       return qcom_cc_really_probe(pdev, &apss_ipq_desc, regmap);

What is this a child of?

> +}
> +
> +static struct platform_driver apss_ipq_driver = {
> +       .probe = apss_ipq_probe,
> +       .driver = {
> +               .name   = "qcom,apss-ipq-clk",
> +       },
> +};