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clk: meson: fractional pll support
Fractional MPLLs are a superset of the existing AmLogic MPLLs. They add in a couple of new bitfields for further dividing the clock rate to achieve rates with fractional hertz. Tested-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Michael Turquette <mturquette@baylibre.com>
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1c50da4f27
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4a47295144
2 changed files with 45 additions and 2 deletions
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@ -53,7 +53,7 @@ static unsigned long meson_clk_pll_recalc_rate(struct clk_hw *hw,
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struct parm *p;
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unsigned long parent_rate_mhz = parent_rate / 1000000;
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unsigned long rate_mhz;
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u16 n, m, od;
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u16 n, m, frac = 0, od, od2 = 0;
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u32 reg;
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p = &pll->n;
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@ -68,7 +68,21 @@ static unsigned long meson_clk_pll_recalc_rate(struct clk_hw *hw,
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reg = readl(pll->base + p->reg_off);
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od = PARM_GET(p->width, p->shift, reg);
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rate_mhz = (parent_rate_mhz * m / n) >> od;
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p = &pll->od2;
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if (p->width) {
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reg = readl(pll->base + p->reg_off);
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od2 = PARM_GET(p->width, p->shift, reg);
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}
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p = &pll->frac;
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if (p->width) {
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reg = readl(pll->base + p->reg_off);
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frac = PARM_GET(p->width, p->shift, reg);
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rate_mhz = (parent_rate_mhz * m + \
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(parent_rate_mhz * frac >> 12)) * 2 / n;
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rate_mhz = rate_mhz >> od >> od2;
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} else
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rate_mhz = (parent_rate_mhz * m / n) >> od >> od2;
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return rate_mhz * 1000000;
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}
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@ -155,6 +169,20 @@ static int meson_clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
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reg = PARM_SET(p->width, p->shift, reg, rate_set->od);
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writel(reg, pll->base + p->reg_off);
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p = &pll->od2;
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if (p->width) {
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reg = readl(pll->base + p->reg_off);
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reg = PARM_SET(p->width, p->shift, reg, rate_set->od2);
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writel(reg, pll->base + p->reg_off);
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}
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p = &pll->frac;
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if (p->width) {
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reg = readl(pll->base + p->reg_off);
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reg = PARM_SET(p->width, p->shift, reg, rate_set->frac);
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writel(reg, pll->base + p->reg_off);
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}
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p = &pll->n;
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ret = meson_clk_pll_wait_lock(pll, p);
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if (ret) {
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@ -40,7 +40,10 @@ struct pll_rate_table {
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u16 m;
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u16 n;
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u16 od;
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u16 od2;
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u16 frac;
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};
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#define PLL_RATE(_r, _m, _n, _od) \
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{ \
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.rate = (_r), \
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@ -49,12 +52,24 @@ struct pll_rate_table {
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.od = (_od), \
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} \
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#define PLL_FRAC_RATE(_r, _m, _n, _od, _od2, _frac) \
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{ \
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.rate = (_r), \
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.m = (_m), \
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.n = (_n), \
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.od = (_od), \
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.od2 = (_od2), \
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.frac = (_frac), \
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} \
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struct meson_clk_pll {
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struct clk_hw hw;
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void __iomem *base;
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struct parm m;
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struct parm n;
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struct parm frac;
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struct parm od;
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struct parm od2;
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const struct pll_rate_table *rate_table;
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unsigned int rate_count;
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spinlock_t *lock;
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