Re: [PATCH v1 2/2] clk: qcom : dispcc: Add support for display port clocks

[Taniya Das <tdas@codeaurora.org>]

Hello Stephen,

On 10/10/2018 2:04 AM, Stephen Boyd wrote:
> Quoting Taniya Das (2018-10-09 06:57:47)
>> diff --git a/drivers/clk/qcom/dispcc-sdm845.c b/drivers/clk/qcom/dispcc-sdm845.c
>> index 0cc4909..6d3136a 100644
>> --- a/drivers/clk/qcom/dispcc-sdm845.c
>> +++ b/drivers/clk/qcom/dispcc-sdm845.c
>> @@ -128,6 +144,100 @@ enum {
>>          },
>>   };
>>
>> +static const struct freq_tbl ftbl_disp_cc_mdss_dp_aux_clk_src[] = {
>> +       F(19200000, P_BI_TCXO, 1, 0, 0),
>> +       { }
>> +};
>> +
>> +static struct clk_rcg2 disp_cc_mdss_dp_aux_clk_src = {
>> +       .cmd_rcgr = 0x219c,
>> +       .mnd_width = 0,
>> +       .hid_width = 5,
>> +       .parent_map = disp_cc_parent_map_2,
>> +       .freq_tbl = ftbl_disp_cc_mdss_dp_aux_clk_src,
>> +       .clkr.hw.init = &(struct clk_init_data){
>> +               .name = "disp_cc_mdss_dp_aux_clk_src",
>> +               .parent_names = disp_cc_parent_names_2,
>> +               .num_parents = 2,
>> +               .flags = CLK_SET_RATE_PARENT,
>> +               .ops = &clk_rcg2_ops,
>> +       },
>> +};
>> +
>> +static const struct freq_tbl ftbl_disp_cc_mdss_dp_crypto_clk_src[] = {
>> +       F(108000, P_DP_PHY_PLL_LINK_CLK,   3,   0,   0),
>> +       F(180000, P_DP_PHY_PLL_LINK_CLK,   3,   0,   0),
>> +       F(360000, P_DP_PHY_PLL_LINK_CLK,   3,   0,   0),
>> +       F(540000, P_DP_PHY_PLL_LINK_CLK,   3,   0,   0),
>> +       { }
>> +};
>> +
>> +static struct clk_rcg2 disp_cc_mdss_dp_crypto_clk_src = {
>> +       .cmd_rcgr = 0x2154,
>> +       .mnd_width = 0,
>> +       .hid_width = 5,
>> +       .parent_map = disp_cc_parent_map_1,
>> +       .freq_tbl = ftbl_disp_cc_mdss_dp_crypto_clk_src,
>> +       .clkr.hw.init = &(struct clk_init_data){
>> +               .name = "disp_cc_mdss_dp_crypto_clk_src",
>> +               .parent_names = disp_cc_parent_names_1,
>> +               .num_parents = 4,
>> +               .flags = CLK_GET_RATE_NOCACHE,
> 
> Why?
> 
>> +               .ops = &clk_rcg2_ops,
>> +       },
>> +};
>> +
>> +static const struct freq_tbl ftbl_disp_cc_mdss_dp_link_clk_src[] = {
>> +       F(162000, P_DP_PHY_PLL_LINK_CLK,   1,   0,   0),
>> +       F(270000, P_DP_PHY_PLL_LINK_CLK,   1,   0,   0),
>> +       F(540000, P_DP_PHY_PLL_LINK_CLK,   1,   0,   0),
>> +       F(810000, P_DP_PHY_PLL_LINK_CLK,   1,   0,   0),
> 
> Are these in kHz? They really look like it and that's bad. Why do we
> need them at all? Just to make sure the display driver picks these exact
> frequencies? It seems like we could just pass whatever number comes in
> up to the parent and see what it can do.
> 

Let me check back the reason we had to make this change.

>> +       { }
>> +};
>> +
>> +static struct clk_rcg2 disp_cc_mdss_dp_link_clk_src = {
>> +       .cmd_rcgr = 0x2138,
>> +       .mnd_width = 0,
>> +       .hid_width = 5,
>> +       .parent_map = disp_cc_parent_map_1,
>> +       .freq_tbl = ftbl_disp_cc_mdss_dp_link_clk_src,
>> +       .clkr.hw.init = &(struct clk_init_data){
>> +               .name = "disp_cc_mdss_dp_link_clk_src",
>> +               .parent_names = disp_cc_parent_names_1,
>> +               .num_parents = 4,
>> +               .flags = CLK_SET_RATE_PARENT,
>> +               .ops = &clk_rcg2_ops,
>> +       },
>> +};
>> +
>> +static struct clk_rcg2 disp_cc_mdss_dp_pixel1_clk_src = {
>> +       .cmd_rcgr = 0x2184,
>> +       .mnd_width = 16,
>> +       .hid_width = 5,
>> +       .parent_map = disp_cc_parent_map_1,
>> +       .clkr.hw.init = &(struct clk_init_data){
>> +               .name = "disp_cc_mdss_dp_pixel1_clk_src",
>> +               .parent_names = disp_cc_parent_names_1,
>> +               .num_parents = 4,
>> +               .flags = CLK_SET_RATE_PARENT,
>> +               .ops = &clk_dp_ops,
>> +       },
>> +};
>> +
>> +static struct clk_rcg2 disp_cc_mdss_dp_pixel_clk_src = {
>> +       .cmd_rcgr = 0x216c,
>> +       .mnd_width = 16,
>> +       .hid_width = 5,
>> +       .parent_map = disp_cc_parent_map_1,
>> +       .clkr.hw.init = &(struct clk_init_data){
>> +               .name = "disp_cc_mdss_dp_pixel_clk_src",
>> +               .parent_names = disp_cc_parent_names_1,
>> +               .num_parents = 4,
>> +               .flags = CLK_SET_RATE_PARENT,
>> +               .ops = &clk_dp_ops,
>> +       },
>> +};
>> +
>>   static const struct freq_tbl ftbl_disp_cc_mdss_esc0_clk_src[] = {
>>          F(19200000, P_BI_TCXO, 1, 0, 0),
>>          { }
>> @@ -391,6 +501,115 @@ enum {
>>          },
>>   };
>>
>> +static struct clk_branch disp_cc_mdss_dp_aux_clk = {
>> +       .halt_reg = 0x2054,
>> +       .halt_check = BRANCH_HALT,
>> +       .clkr = {
>> +               .enable_reg = 0x2054,
>> +               .enable_mask = BIT(0),
>> +               .hw.init = &(struct clk_init_data){
>> +                       .name = "disp_cc_mdss_dp_aux_clk",
>> +                       .parent_names = (const char *[]){
>> +                               "disp_cc_mdss_dp_aux_clk_src",
>> +                       },
>> +                       .num_parents = 1,
>> +                       .flags = CLK_SET_RATE_PARENT,
>> +                       .ops = &clk_branch2_ops,
>> +               },
>> +       },
>> +};
>> +
>> +static struct clk_branch disp_cc_mdss_dp_crypto_clk = {
>> +       .halt_reg = 0x2048,
>> +       .halt_check = BRANCH_HALT,
>> +       .clkr = {
>> +               .enable_reg = 0x2048,
>> +               .enable_mask = BIT(0),
>> +               .hw.init = &(struct clk_init_data){
>> +                       .name = "disp_cc_mdss_dp_crypto_clk",
>> +                       .parent_names = (const char *[]){
>> +                               "disp_cc_mdss_dp_crypto_clk_src",
>> +                       },
>> +                       .num_parents = 1,
>> +                       .flags = CLK_SET_RATE_PARENT,
>> +                       .ops = &clk_branch2_ops,
>> +               },
>> +       },
>> +};
>> +
>> +static struct clk_branch disp_cc_mdss_dp_link_clk = {
>> +       .halt_reg = 0x2040,
>> +       .halt_check = BRANCH_HALT,
>> +       .clkr = {
>> +               .enable_reg = 0x2040,
>> +               .enable_mask = BIT(0),
>> +               .hw.init = &(struct clk_init_data){
>> +                       .name = "disp_cc_mdss_dp_link_clk",
>> +                       .parent_names = (const char *[]){
>> +                               "disp_cc_mdss_dp_link_clk_src",
>> +                       },
>> +                       .num_parents = 1,
>> +                       .flags = CLK_SET_RATE_PARENT,
>> +                       .ops = &clk_branch2_ops,
>> +               },
>> +       },
>> +};
>> +
>> +/* reset state of disp_cc_mdss_dp_link_div_clk_src divider is 0x3 (div 4) */
> 
> Not sure what this comment is for. But it's interesting nonetheless.
> 
>> +static struct clk_branch disp_cc_mdss_dp_link_intf_clk = {
>> +       .halt_reg = 0x2044,
>> +       .halt_check = BRANCH_HALT,
>> +       .clkr = {
>> +               .enable_reg = 0x2044,
>> +               .enable_mask = BIT(0),
>> +               .hw.init = &(struct clk_init_data){
>> +                       .name = "disp_cc_mdss_dp_link_intf_clk",
>> +                       .parent_names = (const char *[]){
>> +                               "disp_cc_mdss_dp_link_clk_src",
>> +                       },
>> +                       .num_parents = 1,
>> +                       .flags = CLK_GET_RATE_NOCACHE,
> 
> Why?
> 

It was a requirement, but let me get back on this too.

>> +                       .ops = &clk_branch2_ops,
>> +               },
>> +       },
>> +};
>> +

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation.

--