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Subject[PATCH] clk: rockchip: Fix PLL bandwidth
Date
In the TRM we see that BWADJ is "a 12-bit bus that selects the values
1-4096 for the bandwidth divider (NB)":
NB = BWADJ[11:0] + 1
The recommended setting of NB: NB = NF / 2.

So:
NB = NF / 2
BWADJ[11:0] + 1 = NF / 2
BWADJ[11:0] = NF / 2 - 1

Right now, we have:

{ \
.rate = _rate##U, \
.nr = _nr, \
.nf = _nf, \
.no = _no, \
.bwadj = (_nf >> 1), \
}

That means we set bwadj to NF / 2, not NF / 2 - 1

All of this is a bit confusing because we specify "NR" (the 1-based
value), "NF" (the 1-based value), "NO" (the 1-based value), but
"BWADJ" (the 0-based value) instead of "NB" (the 1-based value).

Let's change to working with "NB" and fix the off by one error. This
may affect PLL jitter in a small way (hopefully for the better).

Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
drivers/clk/rockchip/clk-pll.c | 18 +++++++++---------
drivers/clk/rockchip/clk-rk3188.c | 2 +-
drivers/clk/rockchip/clk-rk3288.c | 2 +-
drivers/clk/rockchip/clk.h | 8 ++++----
4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/rockchip/clk-pll.c b/drivers/clk/rockchip/clk-pll.c
index 1f88dd1..96903ae 100644
--- a/drivers/clk/rockchip/clk-pll.c
+++ b/drivers/clk/rockchip/clk-pll.c
@@ -120,8 +120,8 @@ static int rockchip_pll_wait_lock(struct rockchip_clk_pll *pll)
#define RK3066_PLLCON0_NR_SHIFT 8
#define RK3066_PLLCON1_NF_MASK 0x1fff
#define RK3066_PLLCON1_NF_SHIFT 0
-#define RK3066_PLLCON2_BWADJ_MASK 0xfff
-#define RK3066_PLLCON2_BWADJ_SHIFT 0
+#define RK3066_PLLCON2_NB_MASK 0xfff
+#define RK3066_PLLCON2_NB_SHIFT 0
#define RK3066_PLLCON3_RESET (1 << 5)
#define RK3066_PLLCON3_PWRDOWN (1 << 1)
#define RK3066_PLLCON3_BYPASS (1 << 0)
@@ -207,8 +207,8 @@ static int rockchip_rk3066_pll_set_rate(struct clk_hw *hw, unsigned long drate,
writel_relaxed(HIWORD_UPDATE(rate->nf - 1, RK3066_PLLCON1_NF_MASK,
RK3066_PLLCON1_NF_SHIFT),
pll->reg_base + RK3066_PLLCON(1));
- writel_relaxed(HIWORD_UPDATE(rate->bwadj, RK3066_PLLCON2_BWADJ_MASK,
- RK3066_PLLCON2_BWADJ_SHIFT),
+ writel_relaxed(HIWORD_UPDATE(rate->nb - 1, RK3066_PLLCON2_NB_MASK,
+ RK3066_PLLCON2_NB_SHIFT),
pll->reg_base + RK3066_PLLCON(2));

/* leave reset and wait the reset_delay */
@@ -261,7 +261,7 @@ static void rockchip_rk3066_pll_init(struct clk_hw *hw)
{
struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
const struct rockchip_pll_rate_table *rate;
- unsigned int nf, nr, no, bwadj;
+ unsigned int nf, nr, no, nb;
unsigned long drate;
u32 pllcon;

@@ -283,13 +283,13 @@ static void rockchip_rk3066_pll_init(struct clk_hw *hw)
nf = ((pllcon >> RK3066_PLLCON1_NF_SHIFT) & RK3066_PLLCON1_NF_MASK) + 1;

pllcon = readl_relaxed(pll->reg_base + RK3066_PLLCON(2));
- bwadj = (pllcon >> RK3066_PLLCON2_BWADJ_SHIFT) & RK3066_PLLCON2_BWADJ_MASK;
+ nb = ((pllcon >> RK3066_PLLCON2_NB_SHIFT) & RK3066_PLLCON2_NB_MASK) + 1;

- pr_debug("%s: pll %s@%lu: nr (%d:%d); no (%d:%d); nf(%d:%d), bwadj(%d:%d)\n",
+ pr_debug("%s: pll %s@%lu: nr (%d:%d); no (%d:%d); nf(%d:%d), nb(%d:%d)\n",
__func__, __clk_get_name(hw->clk), drate, rate->nr, nr,
- rate->no, no, rate->nf, nf, rate->bwadj, bwadj);
+ rate->no, no, rate->nf, nf, rate->nb, nb);
if (rate->nr != nr || rate->no != no || rate->nf != nf
- || rate->bwadj != bwadj) {
+ || rate->nb != nb) {
struct clk *parent = __clk_get_parent(hw->clk);
unsigned long prate;

diff --git a/drivers/clk/rockchip/clk-rk3188.c b/drivers/clk/rockchip/clk-rk3188.c
index edbafbc..0abf22d 100644
--- a/drivers/clk/rockchip/clk-rk3188.c
+++ b/drivers/clk/rockchip/clk-rk3188.c
@@ -817,7 +817,7 @@ static void __init rk3188_clk_init(struct device_node *np)

rate = pll->rate_table;
while (rate->rate > 0) {
- rate->bwadj = 0;
+ rate->nb = 1;
rate++;
}
}
diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
index a8bad7d..0df5bae 100644
--- a/drivers/clk/rockchip/clk-rk3288.c
+++ b/drivers/clk/rockchip/clk-rk3288.c
@@ -84,7 +84,7 @@ static struct rockchip_pll_rate_table rk3288_pll_rates[] = {
RK3066_PLL_RATE( 742500000, 8, 495, 2),
RK3066_PLL_RATE( 696000000, 1, 58, 2),
RK3066_PLL_RATE( 600000000, 1, 50, 2),
- RK3066_PLL_RATE_BWADJ(594000000, 1, 198, 8, 1),
+ RK3066_PLL_RATE_NB(594000000, 1, 198, 8, 1),
RK3066_PLL_RATE( 552000000, 1, 46, 2),
RK3066_PLL_RATE( 504000000, 1, 84, 4),
RK3066_PLL_RATE( 500000000, 3, 125, 2),
diff --git a/drivers/clk/rockchip/clk.h b/drivers/clk/rockchip/clk.h
index 93ea335..dc8ecb2 100644
--- a/drivers/clk/rockchip/clk.h
+++ b/drivers/clk/rockchip/clk.h
@@ -83,16 +83,16 @@ enum rockchip_pll_type {
.nr = _nr, \
.nf = _nf, \
.no = _no, \
- .bwadj = ((_nf) >> 1), \
+ .nb = ((_nf) < 2) ? 1 : (_nf) >> 1, \
}

-#define RK3066_PLL_RATE_BWADJ(_rate, _nr, _nf, _no, _bw) \
+#define RK3066_PLL_RATE_NB(_rate, _nr, _nf, _no, _nb) \
{ \
.rate = _rate##U, \
.nr = _nr, \
.nf = _nf, \
.no = _no, \
- .bwadj = _bw, \
+ .nb = _nb, \
}

struct rockchip_pll_rate_table {
@@ -100,7 +100,7 @@ struct rockchip_pll_rate_table {
unsigned int nr;
unsigned int nf;
unsigned int no;
- unsigned int bwadj;
+ unsigned int nb;
};

/**
--
2.4.3.573.g4eafbef


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