[PATCH 1/3] clk: sunxi-ng: Support fixed post-dividers on NM style clocks

From: Chen-Yu Tsai
Date: Fri Dec 08 2017 - 03:36:15 EST


On the A83T, the audio PLL should have its div1 set to 0, or /1, and
div2 set to 1, or /2. This setting is the default, and is required
to match the sigma-delta modulation parameters from the BSP kernel.

To do this, we first add fixed post-divider to the NM style clocks,
which is the type of clock the audio PLL clock is modeled into.

Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
---
drivers/clk/sunxi-ng/ccu_nm.c | 50 ++++++++++++++++++++++++++++++++-----------
drivers/clk/sunxi-ng/ccu_nm.h | 2 ++
2 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
index 7620aa973a6e..a16de092bf94 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.c
+++ b/drivers/clk/sunxi-ng/ccu_nm.c
@@ -70,11 +70,18 @@ static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct ccu_nm *nm = hw_to_ccu_nm(hw);
+ unsigned long rate;
unsigned long n, m;
u32 reg;

- if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac))
- return ccu_frac_helper_read_rate(&nm->common, &nm->frac);
+ if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) {
+ rate = ccu_frac_helper_read_rate(&nm->common, &nm->frac);
+
+ if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate /= nm->fixed_post_div;
+
+ return rate;
+ }

reg = readl(nm->common.base + nm->common.reg);

@@ -90,15 +97,15 @@ 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;
- }
+ if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm))
+ rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n);
+ else
+ rate = parent_rate * n / m;
+
+ if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate /= nm->fixed_post_div;

- return parent_rate * n / m;
+ return rate;
}

static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
@@ -107,11 +114,20 @@ static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
struct ccu_nm *nm = hw_to_ccu_nm(hw);
struct _ccu_nm _nm;

- if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate))
+ if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate *= nm->fixed_post_div;
+
+ if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
+ if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate /= nm->fixed_post_div;
return rate;
+ }

- if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate))
+ if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
+ if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate /= nm->fixed_post_div;
return rate;
+ }

_nm.min_n = nm->n.min ?: 1;
_nm.max_n = nm->n.max ?: 1 << nm->n.width;
@@ -119,8 +135,12 @@ static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
_nm.max_m = nm->m.max ?: 1 << nm->m.width;

ccu_nm_find_best(*parent_rate, rate, &_nm);
+ rate = *parent_rate * _nm.n / _nm.m;
+
+ if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate /= nm->fixed_post_div;

- return *parent_rate * _nm.n / _nm.m;
+ return rate;
}

static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
@@ -131,6 +151,10 @@ static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long flags;
u32 reg;

+ /* Adjust target rate according to post-dividers */
+ if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate = rate * nm->fixed_post_div;
+
if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
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 c623b0c7a23c..eba586b4c7d0 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.h
+++ b/drivers/clk/sunxi-ng/ccu_nm.h
@@ -36,6 +36,8 @@ struct ccu_nm {
struct ccu_frac_internal frac;
struct ccu_sdm_internal sdm;

+ unsigned int fixed_post_div;
+
struct ccu_common common;
};

--
2.15.0