Re: [PATCH] drm/i915: Changes required to enable DSI Video Mode on CHT

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 14 Jan 2015, "Singh, Gaurav K" <gaurav.k.singh@intel.com> wrote:
> On 12/12/2014 1:03 PM, Singh, Gaurav K wrote:
>>
>> On 12/10/2014 7:38 PM, Gaurav K Singh wrote:
>>> For CHT changes are required for calculating the correct m,n & p with
>>> minimal error +/- for the required DSI clock, so that the correct 
>>> dividor
>>> & ctrl values are written in cck regs for DSI. This patch has been 
>>> tested
>>> on CHT RVP with 1200 x 1920 panel.
>>>
>>> Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/intel_dsi_pll.c |   43 
>>> ++++++++++++++++++++++++++--------
>>>   1 file changed, 33 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c 
>>> b/drivers/gpu/drm/i915/intel_dsi_pll.c
>>> index 8957f10..9236b66 100644
>>> --- a/drivers/gpu/drm/i915/intel_dsi_pll.c
>>> +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
>>> @@ -162,7 +162,8 @@ static u32 dsi_clk_from_pclk(u32 pclk, int 
>>> pixel_format, int lane_count)
>>>     #endif
>>>   -static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp)
>>> +static int dsi_calc_mnp(struct drm_i915_private *dev_priv,
>>> +            u32 dsi_clk, struct dsi_mnp *dsi_mnp)
>>>   {
>>>       u32 m, n, p;
>>>       u32 ref_clk;
>>> @@ -173,6 +174,10 @@ static int dsi_calc_mnp(u32 dsi_clk, struct 
>>> dsi_mnp *dsi_mnp)
>>>       u32 calc_m;
>>>       u32 calc_p;
>>>       u32 m_seed;
>>> +    u32 m_start;
>>> +    u32 m_limit;
>>> +    u32 n_limit;
>>> +    u32 p_limit;
>>>         /* dsi_clk is expected in KHZ */
>>>       if (dsi_clk < 300000 || dsi_clk > 1150000) {
>>> @@ -180,18 +185,33 @@ static int dsi_calc_mnp(u32 dsi_clk, struct 
>>> dsi_mnp *dsi_mnp)
>>>           return -ECHRNG;
>>>       }
>>>   -    ref_clk = 25000;
>>> +    if (IS_CHERRYVIEW(dev_priv->dev)) {
>>> +        ref_clk = 100000;
>>> +        m_start = 70;
>>> +        m_limit = 96;
>>> +        n_limit = 4;
>>> +        p_limit = 6;
>>> +    } else if (IS_VALLEYVIEW(dev_priv->dev)) {
>>> +        ref_clk = 25000;
>>> +        m_start = 62;
>>> +        m_limit = 92;
>>> +        n_limit = 1;
>>> +        p_limit = 6;
>>> +    } else {
>>> +        DRM_ERROR("Unsupported device\n");
>>> +        return -ENODEV;
>>> +    }
>>>       target_dsi_clk = dsi_clk;
>>>       error = 0xFFFFFFFF;
>>>       tmp_error = 0xFFFFFFFF;
>>>       calc_m = 0;
>>>       calc_p = 0;
>>>   -    for (m = 62; m <= 92; m++) {
>>> -        for (p = 2; p <= 6; p++) {
>>> +    for (m = m_start; m <= m_limit; m++) {
>>> +        for (p = 2; p <= p_limit; p++) {
>>>               /* Find the optimal m and p divisors
>>>                  with minimal error +/- the required clock */
>>> -            calc_dsi_clk = (m * ref_clk) / p;
>>> +            calc_dsi_clk = (m * ref_clk) / (p * n_limit);
>>>               if (calc_dsi_clk == target_dsi_clk) {
>>>                   calc_m = m;
>>>                   calc_p = p;
>>> @@ -212,11 +232,14 @@ static int dsi_calc_mnp(u32 dsi_clk, struct 
>>> dsi_mnp *dsi_mnp)
>>>       }
>>>         m_seed = lfsr_converts[calc_m - 62];
>>> -    n = 1;
>>> +    n = n_limit;
>>>       dsi_mnp->dsi_pll_ctrl = 1 << (DSI_PLL_P1_POST_DIV_SHIFT + 
>>> calc_p - 2);
>>> -    dsi_mnp->dsi_pll_div = (n - 1) << DSI_PLL_N1_DIV_SHIFT |
>>> -        m_seed << DSI_PLL_M1_DIV_SHIFT;
>>> -
>>> +    if (IS_CHERRYVIEW(dev_priv->dev))
>>> +        dsi_mnp->dsi_pll_div = (n/2) << DSI_PLL_N1_DIV_SHIFT |
>>> +                m_seed << DSI_PLL_M1_DIV_SHIFT;
>>> +    else
>>> +        dsi_mnp->dsi_pll_div = (n - 1) << DSI_PLL_N1_DIV_SHIFT |
>>> +                m_seed << DSI_PLL_M1_DIV_SHIFT;
>>>       return 0;
>>>   }
>>>   @@ -235,7 +258,7 @@ static void vlv_configure_dsi_pll(struct 
>>> intel_encoder *encoder)
>>>       dsi_clk = dsi_clk_from_pclk(intel_dsi->pclk, 
>>> intel_dsi->pixel_format,
>>>                       intel_dsi->lane_count);
>>>   -    ret = dsi_calc_mnp(dsi_clk, &dsi_mnp);
>>> +    ret = dsi_calc_mnp(dev_priv, dsi_clk, &dsi_mnp);
>>>       if (ret) {
>>>           DRM_DEBUG_KMS("dsi_calc_mnp failed\n");
>>>           return;
>> Hi Jani,
>>
>> Could you please review this patch?
>>
>> With regards,
>> Gaurav
>>
> Hi Jani,
>
> Could you please review this patch?

I did, almost a month ago!
http://mid.mail-archive.com/87h9ws2dbz.fsf@intel.com

Daniel, please pick it up.

Gaurav, please let us know if there are any more pending patches that
we've failed to review or apply!

Thanks,
Jani.


-- 
Jani Nikula, Intel Open Source Technology Center
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