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 <[email protected]> --- drivers/clk/sunxi-ng/ccu_nm.c | 22 +++++++++++++++++++++- drivers/clk/sunxi-ng/ccu_nm.h | 25 +++++++++++++++++++++++++ 2 files changed, 46 insertions(+), 1 deletion(-) 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, \ -- 2.14.2 -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
