Date:   Mon, 4 May 2020 11:40:37 +0530
From:   Sivaprakash Murugesan <sivaprak@...eaurora.org>
To:     Stephen Boyd <sboyd@...nel.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
Subject: Re: [PATCH V3 5/8] clk: qcom: Add ipq apss clock controller

Hi Stephen,

On 4/22/2020 2:34 PM, Stephen Boyd wrote:
> 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.
ok.
>
>> 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.
ok
>
>> +       help
>> +         Support for APSS clock controller on ipq platform devices. The
> Maybe say "IPQ platforms" and drop the devices part?
ok
>
>> +         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.
Just realized that it need not be critical. will remove it in next patch.
>
>> +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?
this is child of qcom apcs mailbox driver. will add compilation 
dependency on next patch.

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