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Date:   Mon, 17 Aug 2020 11:06:51 -0700
From:   Tanmay Shah <tanmay@codeaurora.org>
To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc:     devicetree@vger.kernel.org, airlied@linux.ie,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, swboyd@chromium.org,
        khsieh@codeaurora.org, seanpaul@chromium.org,
        abhinavk@codeaurora.org, Vara Reddy <varar@codeaurora.org>,
        aravindh@codeaurora.org, freedreno@lists.freedesktop.org,
        Chandan Uddaraju <chandanu@codeaurora.org>,
        dri-devel <dri-devel-bounces@lists.freedesktop.org>
Subject: Re: [PATCH v10 3/5] drm/msm/dp: add support for DP PLL driver
In-Reply-To: <28b1f678-ab8f-cf6a-af9f-fcd79131bdc1@linaro.org>
References: <20200812044223.19279-1-tanmay@codeaurora.org>
 <20200812044223.19279-4-tanmay@codeaurora.org>
 <821b5cf9-5ca0-7026-fd99-9a32285ed030@linaro.org>
 <f6b330778c07abd3003da9acab4d3398@codeaurora.org>
 <28b1f678-ab8f-cf6a-af9f-fcd79131bdc1@linaro.org>
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On 2020-08-15 04:45, Dmitry Baryshkov wrote:
> On 15/08/2020 02:22, Tanmay Shah wrote:
>> On 2020-08-14 10:05, Dmitry Baryshkov wrote:
>>> On 12/08/2020 07:42, Tanmay Shah wrote:
>>>> From: Chandan Uddaraju <chandanu@codeaurora.org>
>>>> 
>>>> Add the needed DP PLL specific files to support
>>>> display port interface on msm targets.
>>> 
>>> [skipped]
>>> 
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_pll_private.h 
>>>> b/drivers/gpu/drm/msm/dp/dp_pll_private.h
>>>> new file mode 100644
>>>> index 000000000000..475ba6ed59ab
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_pll_private.h
>>>> @@ -0,0 +1,98 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>>> +/*
>>>> + * Copyright (c) 2016-2020, The Linux Foundation. All rights 
>>>> reserved.
>>>> + */
>>>> +
>>>> +#ifndef __DP_PLL_10NM_H
>>>> +#define __DP_PLL_10NM_H
>>>> +
>>>> +#include "dp_pll.h"
>>>> +#include "dp_reg.h"
>>>> +
>>>> +#define DP_VCO_HSCLK_RATE_1620MHZDIV1000    1620000UL
>>>> +#define DP_VCO_HSCLK_RATE_2700MHZDIV1000    2700000UL
>>>> +#define DP_VCO_HSCLK_RATE_5400MHZDIV1000    5400000UL
>>>> +#define DP_VCO_HSCLK_RATE_8100MHZDIV1000    8100000UL
>>>> +
>>>> +#define NUM_DP_CLOCKS_MAX            6
>>>> +
>>>> +#define DP_PHY_PLL_POLL_SLEEP_US        500
>>>> +#define DP_PHY_PLL_POLL_TIMEOUT_US        10000
>>>> +
>>>> +#define DP_VCO_RATE_8100MHZDIV1000        8100000UL
>>>> +#define DP_VCO_RATE_9720MHZDIV1000        9720000UL
>>>> +#define DP_VCO_RATE_10800MHZDIV1000        10800000UL
>>>> +
>>>> +struct dp_pll_vco_clk {
>>>> +    struct clk_hw hw;
>>>> +    unsigned long    rate;        /* current vco rate */
>>>> +    u64        min_rate;    /* min vco rate */
>>>> +    u64        max_rate;    /* max vco rate */
>>>> +    void        *priv;
>>>> +};
>>>> +
>>>> +struct dp_pll_db {
>>> 
>>> This struct should probably go into dp_pll_10nm.c. dp_pll_7nm.c, for
>>> example, will use slightly different structure.
>>> 
>> 
>> Sure, it sounds good. I will give it try. Thanks!
>> 
>>>> +    struct msm_dp_pll *base;
>>>> +
>>>> +    int id;
>>>> +    struct platform_device *pdev;
>>>> +
>>>> +    /* private clocks: */
>>>> +    bool fixed_factor_clk[NUM_DP_CLOCKS_MAX];
>>>> +    struct clk_hw *hws[NUM_DP_CLOCKS_MAX];
>>> 
>>> Then these two fields can use exact number of clocks rather than
>>> NUM_DP_CLOCKS_MAX.
>>> 
>> 
>> I didn't get this. I think NUM_DP_CLOCKS_MAX is doing same?
> 
> Not exactly. We'd need fixed_factor_clk[4] for 10nm rather than 6.
> It's not that important, just a small nitpick.
> 
> 
>>>> +    u32 num_hws;
>>>> +
>>>> +    /* lane and orientation settings */
>>>> +    u8 lane_cnt;
>>>> +    u8 orientation;
>>>> +
>>>> +    /* COM PHY settings */
>>>> +    u32 hsclk_sel;
>>>> +    u32 dec_start_mode0;
>>>> +    u32 div_frac_start1_mode0;
>>>> +    u32 div_frac_start2_mode0;
>>>> +    u32 div_frac_start3_mode0;
>>>> +    u32 integloop_gain0_mode0;
>>>> +    u32 integloop_gain1_mode0;
>>>> +    u32 vco_tune_map;
>>>> +    u32 lock_cmp1_mode0;
>>>> +    u32 lock_cmp2_mode0;
>>>> +    u32 lock_cmp3_mode0;
>>>> +    u32 lock_cmp_en;
>>>> +
>>>> +    /* PHY vco divider */
>>>> +    u32 phy_vco_div;
>>>> +    /*
>>>> +     * Certain pll's needs to update the same vco rate after resume 
>>>> in
>>>> +     * suspend/resume scenario. Cached the vco rate for such plls.
>>>> +     */
>>>> +    unsigned long    vco_cached_rate;
>>>> +    u32        cached_cfg0;
>>>> +    u32        cached_cfg1;
>>>> +    u32        cached_outdiv;
>>>> +
>>>> +    uint32_t index;
>>>> +};
>>>> +
>>>> +static inline struct dp_pll_vco_clk *to_dp_vco_hw(struct clk_hw 
>>>> *hw)
>>>> +{
>>>> +    return container_of(hw, struct dp_pll_vco_clk, hw);
>>>> +}
>>>> +
>>>> +#define to_msm_dp_pll(vco) ((struct msm_dp_pll *)vco->priv)
>>>> +
>>>> +#define to_dp_pll_db(x)    ((struct dp_pll_db *)x->priv)
>>>> +
>>>> +int dp_vco_set_rate_10nm(struct clk_hw *hw, unsigned long rate,
>>>> +                unsigned long parent_rate);
>>>> +unsigned long dp_vco_recalc_rate_10nm(struct clk_hw *hw,
>>>> +                unsigned long parent_rate);
>>>> +long dp_vco_round_rate_10nm(struct clk_hw *hw, unsigned long rate,
>>>> +                unsigned long *parent_rate);
>>>> +int dp_vco_prepare_10nm(struct clk_hw *hw);
>>>> +void dp_vco_unprepare_10nm(struct clk_hw *hw);
>>>> +
>>>> +int msm_dp_pll_10nm_init(struct msm_dp_pll *dp_pll, int id);
>>>> +void msm_dp_pll_10nm_deinit(struct msm_dp_pll *dp_pll);
>>> 
>>> These functions don't seem to be used outside of dp_pll_10nm. What
>>> about making them static?
>> 
>> I can't declare static to "init" and "deinit" as they are exported to 
>> dp_pll.c.
>> Rest of them I can move to dp_pll_10nm and then define static.
> 
> Please exuse me for not being exact enough. Of course I meant
> dp_vco_FOO_10nm() functions, not init/exit.
> 
Ok got it. Sorry I didn't mean to nitpick here.

> BTW: as I'm looking onto 7nm dp pll, which naming would you prefer?
> 
I didn't get this. Did you mean naming convention of functions and 
structure between
7nm and 10 nm? Could you point me where 7nm dp pll code is posted?

> We can have separate DP_PLL_10nm/DP_PLL_7nm namespaces (as DSI PLLs
> do) or I can override only a set of constants (like downstream driver
> does).

Having separate namespace sounds good.