[PATCH v2 01/16] clk: sunxi-ng: Add check for minimal rate to NM PLLs

Jernej Skrabec
2018-02-27T22:26:46Z

Some NM PLLs doesn't work well when their output clock rate is set below
certain rate.

Add support for that constrain.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
drivers/clk/sunxi-ng/ccu_nm.c | 11 +++++++----
drivers/clk/sunxi-ng/ccu_nm.h | 27 +++++++++++++++++++++++++++
2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
index a16de092bf94..7fc743c78c1b 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.c
+++ b/drivers/clk/sunxi-ng/ccu_nm.c
@@ -20,7 +20,7 @@ struct _ccu_nm {
};

static void ccu_nm_find_best(unsigned long parent, unsigned long rate,
- struct _ccu_nm *nm)
+ unsigned long min_rate, struct _ccu_nm *nm)
{
unsigned long best_rate = 0;
unsigned long best_n = 0, best_m = 0;
@@ -30,7 +30,7 @@ static void ccu_nm_find_best(unsigned long parent, unsigned long rate,
for (_m = nm->min_m; _m <= nm->max_m; _m++) {
unsigned long tmp_rate = parent * _n / _m;

- if (tmp_rate > rate)
+ if (tmp_rate > rate || tmp_rate < min_rate)
continue;

if ((rate - tmp_rate) < (rate - best_rate)) {
@@ -117,6 +117,9 @@ static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate *= nm->fixed_post_div;

+ if (rate < nm->min_rate)
+ rate = nm->min_rate;
+
if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nm->fixed_post_div;
@@ -134,7 +137,7 @@ static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
_nm.min_m = 1;
_nm.max_m = nm->m.max ?: 1 << nm->m.width;

- ccu_nm_find_best(*parent_rate, rate, &_nm);
+ ccu_nm_find_best(*parent_rate, rate, nm->min_rate, &_nm);
rate = *parent_rate * _nm.n / _nm.m;

if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
@@ -186,7 +189,7 @@ static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
&_nm.m, &_nm.n);
} else {
ccu_sdm_helper_disable(&nm->common, &nm->sdm);
- ccu_nm_find_best(parent_rate, rate, &_nm);
+ ccu_nm_find_best(parent_rate, rate, nm->min_rate, &_nm);
}

spin_lock_irqsave(nm->common.lock, flags);
diff --git a/drivers/clk/sunxi-ng/ccu_nm.h b/drivers/clk/sunxi-ng/ccu_nm.h
index eba586b4c7d0..1d8b459c50b7 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.h
+++ b/drivers/clk/sunxi-ng/ccu_nm.h
@@ -37,6 +37,7 @@ struct ccu_nm {
struct ccu_sdm_internal sdm;

unsigned int fixed_post_div;
+ unsigned int min_rate;

struct ccu_common common;
};
@@ -88,6 +89,32 @@ struct ccu_nm {
}, \
}

+#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN(_struct, _name, _parent, \
+ _reg, _min_rate, \
+ _nshift, _nwidth, \
+ _mshift, _mwidth, \
+ _frac_en, _frac_sel, \
+ _frac_rate_0, _frac_rate_1,\
+ _gate, _lock, _flags) \
+ struct ccu_nm _struct = { \
+ .enable = _gate, \
+ .lock = _lock, \
+ .n = _SUNXI_CCU_MULT(_nshift, _nwidth), \
+ .m = _SUNXI_CCU_DIV(_mshift, _mwidth), \
+ .frac = _SUNXI_CCU_FRAC(_frac_en, _frac_sel, \
+ _frac_rate_0, \
+ _frac_rate_1), \
+ .min_rate = _min_rate, \
+ .common = { \
+ .reg = _reg, \
+ .features = CCU_FEATURE_FRACTIONAL, \
+ .hw.init = CLK_HW_INIT(_name, \
+ _parent, \
+ &ccu_nm_ops, \
+ _flags), \
+ }, \
+ }
+
#define SUNXI_CCU_NM_WITH_GATE_LOCK(_struct, _name, _parent, _reg, \
_nshift, _nwidth, \
_mshift, _mwidth, \
--
2.16.2