The Allwinner A64 manual lists the following constraint for the
PLL-VIDEO0 clock: 8 <= N/M <= 25

The PLL-MIPI clock is implemented as ccu_nm. Therefore, add support for
this constraint.

Signed-off-by: Frank Oltmanns <fr...@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_nm.c | 21 +++++++++++++++++++--
 drivers/clk/sunxi-ng/ccu_nm.h | 34 ++++++++++++++++++++++++++++++++--
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
index ffac3deb89d6..cfc6981e398b 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.c
+++ b/drivers/clk/sunxi-ng/ccu_nm.c
@@ -27,6 +27,19 @@ static unsigned long ccu_nm_calc_rate(unsigned long parent,
        return rate;
 }
 
+static bool ccu_nm_is_valid_rate(struct ccu_common *common, unsigned long n, 
unsigned long m)
+{
+       struct ccu_nm *nm = container_of(common, struct ccu_nm, common);
+
+       if (nm->max_nm_ratio && (n > nm->max_nm_ratio * m))
+               return false;
+
+       if (nm->min_nm_ratio && (n < nm->min_nm_ratio * m))
+               return false;
+
+       return true;
+}
+
 static unsigned long ccu_nm_find_best(struct ccu_common *common, unsigned long 
parent,
                                      unsigned long rate, struct _ccu_nm *nm)
 {
@@ -36,8 +49,12 @@ static unsigned long ccu_nm_find_best(struct ccu_common 
*common, unsigned long p
 
        for (_n = nm->min_n; _n <= nm->max_n; _n++) {
                for (_m = nm->min_m; _m <= nm->max_m; _m++) {
-                       unsigned long tmp_rate = ccu_nm_calc_rate(parent,
-                                                                 _n, _m);
+                       unsigned long tmp_rate;
+
+                       if (!ccu_nm_is_valid_rate(common, _n, _m))
+                               continue;
+
+                       tmp_rate = ccu_nm_calc_rate(parent, _n, _m);
 
                        if (ccu_is_better_rate(common, rate, tmp_rate, 
best_rate)) {
                                best_rate = tmp_rate;
diff --git a/drivers/clk/sunxi-ng/ccu_nm.h b/drivers/clk/sunxi-ng/ccu_nm.h
index 93c11693574f..0075df6d9697 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.h
+++ b/drivers/clk/sunxi-ng/ccu_nm.h
@@ -31,6 +31,8 @@ struct ccu_nm {
        unsigned int            fixed_post_div;
        unsigned int            min_rate;
        unsigned int            max_rate;
+       unsigned long           min_nm_ratio; /* minimum value for m/n */
+       unsigned long           max_nm_ratio; /* maximum value for m/n */
 
        struct ccu_common       common;
 };
@@ -108,7 +110,8 @@ struct ccu_nm {
                },                                                      \
        }
 
-#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,  \
+#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT_NM_RATIO(                
\
+                                                _struct, _name,        \
                                                 _parent, _reg,         \
                                                 _min_rate, _max_rate,  \
                                                 _nshift, _nwidth,      \
@@ -117,7 +120,9 @@ struct ccu_nm {
                                                 _frac_rate_0,          \
                                                 _frac_rate_1,          \
                                                 _gate, _lock, _flags,  \
-                                                _features)             \
+                                                _features,             \
+                                                _min_nm_ratio,         \
+                                                _max_nm_ratio)         \
        struct ccu_nm _struct = {                                       \
                .enable         = _gate,                                \
                .lock           = _lock,                                \
@@ -128,6 +133,8 @@ struct ccu_nm {
                                                  _frac_rate_1),        \
                .min_rate       = _min_rate,                            \
                .max_rate       = _max_rate,                            \
+               .min_nm_ratio   = _min_nm_ratio,                        \
+               .max_nm_ratio   = _max_nm_ratio,                        \
                .common         = {                                     \
                        .reg            = _reg,                         \
                        .features       = _features,                    \
@@ -138,6 +145,29 @@ struct ccu_nm {
                },                                                      \
        }
 
+#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,  \
+                                                _parent, _reg,         \
+                                                _min_rate, _max_rate,  \
+                                                _nshift, _nwidth,      \
+                                                _mshift, _mwidth,      \
+                                                _frac_en, _frac_sel,   \
+                                                _frac_rate_0,          \
+                                                _frac_rate_1,          \
+                                                _gate, _lock, _flags,  \
+                                                _features)             \
+       SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT_NM_RATIO(         \
+                                               _struct, _name,         \
+                                               _parent, _reg,          \
+                                               _min_rate, _max_rate,   \
+                                               _nshift, _nwidth,       \
+                                               _mshift, _mwidth,       \
+                                               _frac_en, _frac_sel,    \
+                                               _frac_rate_0,           \
+                                               _frac_rate_1,           \
+                                               _gate, _lock, _flags,   \
+                                               _features,              \
+                                               0, 0)
+
 #define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX(_struct, _name,       \
                                                 _parent, _reg,         \
                                                 _min_rate, _max_rate,  \

-- 
2.43.0

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