Convert the limited MIPI clock calculations to a full range of settings
based on math including H/W limitation validation.
Since the required DSI division setting must be specified from external
sources before calculations, expose a new API to set it.

Signed-off-by: Chris Brandt <[email protected]>
Signed-off-by: hienhuynh <[email protected]>
Signed-off-by: Nghia Vo <[email protected]>
Reviewed-by: Biju Das <[email protected]>
Tested-by: Biju Das <[email protected]>

---
v1->v2:
- Remove unnecessary parentheses
- Add target argument to new API
- DPI mode has more restrictions on DIV_A and DIV_B

v2->v3:
- Removed Empty lines (Hugo)
- Add dummy for compile-testing CONFIG_CLK_RZG2L=n case (Geert)
- Renamed label found_dsi_div to calc_pll_clk (Hugo)
- Renamed label found_clk to clk_valid (Hugo)
- Removed 'found' var because not needed
- Move 'foutpostdiv_rate =' after if(foutvco_rate > 1500000000) (Hugo)
- Move PLL5_TARGET_* for new API to renesas.h (Hugo,Geert)
- Convert #define macros PLL5_TARGET_* to enum (Geert)
- static {unsigned} int dsi_div_ab; (Geert)
- {unsigned} int a, b;  (Geert)
- Change "((1 << a) * (b + 1))" to "(b + 1) << a"  (Geert)
- Change "foutvco_rate = rate * (1 << xxx ) * ..." to " = rate * ... * << xxx 
(Geert)
- Move (u64) outside of modulo operation to avoid helper on 32-bit compiles 
(Geert)
- Change DIV_ROUND_CLOSEST_ULL() to DIV_ROUND_CLOSEST() (Geert)
- void rzg2l_cpg_dsi_div_set_divider({unsinged} int divider, int target)
- Change "dsi_div_ab = (1 << AAA) * (BBB + 1)" to " = (BBB + 1) << AAA (Geert)
- Added Reviewed-by and Tested-by (Biju)
---
 drivers/clk/renesas/rzg2l-cpg.c | 129 +++++++++++++++++++++++++++++---
 include/linux/clk/renesas.h     |  11 +++
 2 files changed, 130 insertions(+), 10 deletions(-)

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 07909e80bae2..0e9362c2ca95 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -74,6 +74,19 @@
 #define MSTOP_OFF(conf)                FIELD_GET(GENMASK(31, 16), (conf))
 #define MSTOP_MASK(conf)       FIELD_GET(GENMASK(15, 0), (conf))
 
+#define PLL5_FOUTVCO_MIN       800000000
+#define PLL5_FOUTVCO_MAX       3000000000
+#define PLL5_POSTDIV_MIN       1
+#define PLL5_POSTDIV_MAX       7
+#define PLL5_POSTDIV_DEF       1
+#define PLL5_REFDIV_MIN                1
+#define PLL5_REFDIV_MAX                2
+#define PLL5_REFDIV_DEF                1
+#define PLL5_INTIN_MIN         20
+#define PLL5_INTIN_MAX         320
+#define PLL5_INTIN_DEF         125
+#define PLL5_FRACIN_DEF                0
+
 /**
  * struct clk_hw_data - clock hardware data
  * @hw: clock hw
@@ -129,6 +142,12 @@ struct rzg2l_pll5_param {
        u8 pl5_spread;
 };
 
+/* PLL5 output will be used for DPI or MIPI-DSI */
+static int dsi_div_target = PLL5_TARGET_DPI;
+
+/* Required division ratio for MIPI D-PHY clock changes depending on 
resolution and lanes. */
+static unsigned int dsi_div_ab;
+
 struct rzg2l_pll5_mux_dsi_div_param {
        u8 clksrc;
        u8 dsi_div_a;
@@ -557,23 +576,104 @@ rzg2l_cpg_sd_mux_clk_register(const struct cpg_core_clk 
*core,
 }
 
 static unsigned long
-rzg2l_cpg_get_foutpostdiv_rate(struct rzg2l_pll5_param *params,
+rzg2l_cpg_get_foutpostdiv_rate(struct rzg2l_cpg_priv *priv,
+                              struct rzg2l_pll5_param *params,
                               unsigned long rate)
 {
        unsigned long foutpostdiv_rate, foutvco_rate;
+       u8 div = 1;
+       unsigned int a, b;
+
+       if (priv->mux_dsi_div_params.clksrc)
+               div = 2;
+
+       /* Calculate the DIV_DSI_A and DIV_DSI_B based on the final DIV DSI */
+       for (a = 0; a < 4; a++) {
+               if (dsi_div_target == PLL5_TARGET_DPI && a == 0)
+                       continue;       /* 1/1 div not supported for DIV_DSI_A 
for DPI */
+
+               for (b = 0; b < 16; b++) {
+                       if (dsi_div_target == PLL5_TARGET_DPI && b != 0)
+                               continue;       /* Only 1/1 div supported for 
DIV_DSI_B in DPI */
 
-       params->pl5_intin = rate / MEGA;
-       params->pl5_fracin = div_u64(((u64)rate % MEGA) << 24, MEGA);
-       params->pl5_refdiv = 2;
-       params->pl5_postdiv1 = 1;
-       params->pl5_postdiv2 = 1;
+                       if ((b + 1) << a == dsi_div_ab) {
+                               priv->mux_dsi_div_params.dsi_div_a = a;
+                               priv->mux_dsi_div_params.dsi_div_b = b;
+
+                               goto calc_pll_clk;
+                       }
+               }
+       }
+
+calc_pll_clk:
+       /*
+        * Below conditions must be set for PLL5 parameters:
+        * - REFDIV must be between 1 and 2.
+        * - POSTDIV1/2 must be between 1 and 7.
+        * - INTIN must be between 20 and 320.
+        * - FOUTVCO must be between 800MHz and 3000MHz.
+        */
+       for (params->pl5_postdiv1 = PLL5_POSTDIV_MIN;
+            params->pl5_postdiv1 < PLL5_POSTDIV_MAX + 1;
+            params->pl5_postdiv1++) {
+               for (params->pl5_postdiv2 = PLL5_POSTDIV_MIN;
+                    params->pl5_postdiv2 < PLL5_POSTDIV_MAX + 1;
+                    params->pl5_postdiv2++) {
+                       foutvco_rate = rate * 
(priv->mux_dsi_div_params.dsi_div_b + 1) * div *
+                                      params->pl5_postdiv1 * 
params->pl5_postdiv2 <<
+                                      priv->mux_dsi_div_params.dsi_div_a;
+
+                       if (foutvco_rate < PLL5_FOUTVCO_MIN + 1 ||
+                           foutvco_rate > PLL5_FOUTVCO_MAX - 1)
+                               continue;
+
+                       for (params->pl5_refdiv = PLL5_REFDIV_MIN;
+                            params->pl5_refdiv < PLL5_REFDIV_MAX + 1;
+                            params->pl5_refdiv++) {
+                               params->pl5_intin = (foutvco_rate * 
params->pl5_refdiv) /
+                                                   (EXTAL_FREQ_IN_MEGA_HZ * 
MEGA);
+                               if (params->pl5_intin < PLL5_INTIN_MIN + 1 ||
+                                   params->pl5_intin > PLL5_INTIN_MAX - 1)
+                                       continue;
+                               params->pl5_fracin = div_u64(((u64)
+                                                    (foutvco_rate * 
params->pl5_refdiv) %
+                                                    (EXTAL_FREQ_IN_MEGA_HZ * 
MEGA)) << 24,
+                                                    EXTAL_FREQ_IN_MEGA_HZ * 
MEGA);
+
+                               params->pl5_fracin = div_u64((u64)
+                                                    ((foutvco_rate * 
params->pl5_refdiv) %
+                                                    (EXTAL_FREQ_IN_MEGA_HZ * 
MEGA)) << 24,
+                                                    EXTAL_FREQ_IN_MEGA_HZ * 
MEGA);
+
+                               goto clk_valid;
+                       }
+               }
+       }
+
+       /* Set defaults since valid clock was not found */
+       params->pl5_intin = PLL5_INTIN_DEF;
+       params->pl5_fracin = PLL5_FRACIN_DEF;
+       params->pl5_refdiv = PLL5_REFDIV_DEF;
+       params->pl5_postdiv1 = PLL5_POSTDIV_DEF;
+       params->pl5_postdiv2 = PLL5_POSTDIV_DEF;
+
+clk_valid:
        params->pl5_spread = 0x16;
 
        foutvco_rate = div_u64(mul_u32_u32(EXTAL_FREQ_IN_MEGA_HZ * MEGA,
                                           (params->pl5_intin << 24) + 
params->pl5_fracin),
                               params->pl5_refdiv) >> 24;
-       foutpostdiv_rate = DIV_ROUND_CLOSEST_ULL(foutvco_rate,
-                                                params->pl5_postdiv1 * 
params->pl5_postdiv2);
+
+       /* If foutvco is above 1.5GHz, change parent and recalculate */
+       if (priv->mux_dsi_div_params.clksrc && foutvco_rate > 1500000000) {
+               priv->mux_dsi_div_params.clksrc = 0;
+               dsi_div_ab *= 2;
+               dsi_div_target = PLL5_TARGET_DSI;       /* Assume MIPI-DSI */
+               return rzg2l_cpg_get_foutpostdiv_rate(priv, params, rate);
+       }
+
+       foutpostdiv_rate = DIV_ROUND_CLOSEST(foutvco_rate,
+                                            params->pl5_postdiv1 * 
params->pl5_postdiv2);
 
        return foutpostdiv_rate;
 }
@@ -607,7 +707,7 @@ static unsigned long rzg2l_cpg_get_vclk_parent_rate(struct 
clk_hw *hw,
        struct rzg2l_pll5_param params;
        unsigned long parent_rate;
 
-       parent_rate = rzg2l_cpg_get_foutpostdiv_rate(&params, rate);
+       parent_rate = rzg2l_cpg_get_foutpostdiv_rate(priv, &params, rate);
 
        if (priv->mux_dsi_div_params.clksrc)
                parent_rate /= 2;
@@ -626,6 +726,13 @@ static int rzg2l_cpg_dsi_div_determine_rate(struct clk_hw 
*hw,
        return 0;
 }
 
+void rzg2l_cpg_dsi_div_set_divider(unsigned int divider, int target)
+{
+       dsi_div_ab = divider;
+       dsi_div_target = target;
+}
+EXPORT_SYMBOL_GPL(rzg2l_cpg_dsi_div_set_divider);
+
 static int rzg2l_cpg_dsi_div_set_rate(struct clk_hw *hw,
                                      unsigned long rate,
                                      unsigned long parent_rate)
@@ -858,7 +965,7 @@ static int rzg2l_cpg_sipll5_set_rate(struct clk_hw *hw,
 
        vclk_rate = rzg2l_cpg_get_vclk_rate(hw, rate);
        sipll5->foutpostdiv_rate =
-               rzg2l_cpg_get_foutpostdiv_rate(&params, vclk_rate);
+               rzg2l_cpg_get_foutpostdiv_rate(priv, &params, vclk_rate);
 
        /* Put PLL5 into standby mode */
        writel(CPG_SIPLL5_STBY_RESETB_WEN, priv->base + CPG_SIPLL5_STBY);
@@ -948,6 +1055,8 @@ rzg2l_cpg_sipll5_register(const struct cpg_core_clk *core,
        priv->mux_dsi_div_params.clksrc = 1; /* Use clk src 1 for DSI */
        priv->mux_dsi_div_params.dsi_div_a = 1; /* Divided by 2 */
        priv->mux_dsi_div_params.dsi_div_b = 2; /* Divided by 3 */
+       dsi_div_ab = (priv->mux_dsi_div_params.dsi_div_b + 1) <<
+                    priv->mux_dsi_div_params.dsi_div_a;
 
        return clk_hw->clk;
 }
diff --git a/include/linux/clk/renesas.h b/include/linux/clk/renesas.h
index 0ebbe2f0b45e..f2edd1f4a6d9 100644
--- a/include/linux/clk/renesas.h
+++ b/include/linux/clk/renesas.h
@@ -16,6 +16,11 @@ struct device;
 struct device_node;
 struct generic_pm_domain;
 
+enum {
+       PLL5_TARGET_DPI,
+       PLL5_TARGET_DSI
+};
+
 void cpg_mstp_add_clk_domain(struct device_node *np);
 #ifdef CONFIG_CLK_RENESAS_CPG_MSTP
 int cpg_mstp_attach_dev(struct generic_pm_domain *unused, struct device *dev);
@@ -32,4 +37,10 @@ void cpg_mssr_detach_dev(struct generic_pm_domain *unused, 
struct device *dev);
 #define cpg_mssr_attach_dev    NULL
 #define cpg_mssr_detach_dev    NULL
 #endif
+
+#ifdef CONFIG_CLK_RZG2L
+void rzg2l_cpg_dsi_div_set_divider(unsigned int divider, int target);
+#else
+#define rzg2l_cpg_dsi_div_set_divider  NULL
+#endif
 #endif
-- 
2.50.1

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