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authorChen-Yu Tsai <wens@csie.org>2017-10-12 16:37:00 +0800
committerMaxime Ripard <maxime.ripard@free-electrons.com>2017-10-13 09:27:13 +0200
commit392ba5fafcdf1969d1abd9a637cc40c45f4781bc (patch)
treef624600dd29c6a4f8f09ea41b5ab18697496b2f9
parent05d2eaac96d4284b0967cc522ad22f6f23fdf82a (diff)
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clk: sunxi-ng: nm: Add support for sigma-delta modulation
Some of the N-M-style clocks, namely the PLLs, support sigma-delta modulation to do fractional-N frequency synthesis. This is used in the audio PLL to generate the exact frequency the audio blocks need. These frequencies can not be generated with integer N-M factors. Signed-off-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
-rw-r--r--drivers/clk/sunxi-ng/ccu_nm.c22
-rw-r--r--drivers/clk/sunxi-ng/ccu_nm.h25
2 files changed, 46 insertions, 1 deletions
diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
index 84a5e7f17f6f..7620aa973a6e 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.c
+++ b/drivers/clk/sunxi-ng/ccu_nm.c
@@ -90,6 +90,14 @@ static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
if (!m)
m++;
+ if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm)) {
+ unsigned long rate =
+ ccu_sdm_helper_read_rate(&nm->common, &nm->sdm,
+ m, n);
+ if (rate)
+ return rate;
+ }
+
return parent_rate * n / m;
}
@@ -102,6 +110,9 @@ static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate))
return rate;
+ if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate))
+ return rate;
+
_nm.min_n = nm->n.min ?: 1;
_nm.max_n = nm->n.max ?: 1 << nm->n.width;
_nm.min_m = 1;
@@ -143,7 +154,16 @@ static int ccu_nm_set_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);
+ if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
+ ccu_sdm_helper_enable(&nm->common, &nm->sdm, rate);
+
+ /* Sigma delta modulation requires specific N and M factors */
+ ccu_sdm_helper_get_factors(&nm->common, &nm->sdm, rate,
+ &_nm.m, &_nm.n);
+ } else {
+ ccu_sdm_helper_disable(&nm->common, &nm->sdm);
+ ccu_nm_find_best(parent_rate, 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 e87fd186da78..c623b0c7a23c 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.h
+++ b/drivers/clk/sunxi-ng/ccu_nm.h
@@ -20,6 +20,7 @@
#include "ccu_div.h"
#include "ccu_frac.h"
#include "ccu_mult.h"
+#include "ccu_sdm.h"
/*
* struct ccu_nm - Definition of an N-M clock
@@ -33,10 +34,34 @@ struct ccu_nm {
struct ccu_mult_internal n;
struct ccu_div_internal m;
struct ccu_frac_internal frac;
+ struct ccu_sdm_internal sdm;
struct ccu_common common;
};
+#define SUNXI_CCU_NM_WITH_SDM_GATE_LOCK(_struct, _name, _parent, _reg, \
+ _nshift, _nwidth, \
+ _mshift, _mwidth, \
+ _sdm_table, _sdm_en, \
+ _sdm_reg, _sdm_reg_en, \
+ _gate, _lock, _flags) \
+ struct ccu_nm _struct = { \
+ .enable = _gate, \
+ .lock = _lock, \
+ .n = _SUNXI_CCU_MULT(_nshift, _nwidth), \
+ .m = _SUNXI_CCU_DIV(_mshift, _mwidth), \
+ .sdm = _SUNXI_CCU_SDM(_sdm_table, _sdm_en, \
+ _sdm_reg, _sdm_reg_en),\
+ .common = { \
+ .reg = _reg, \
+ .features = CCU_FEATURE_SIGMA_DELTA_MOD, \
+ .hw.init = CLK_HW_INIT(_name, \
+ _parent, \
+ &ccu_nm_ops, \
+ _flags), \
+ }, \
+ }
+
#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK(_struct, _name, _parent, _reg, \
_nshift, _nwidth, \
_mshift, _mwidth, \