Messages in this thread | | | From | Martin Blumenstingl <> | Date | Fri, 20 Jul 2018 21:17:30 +0200 | Subject | Re: [PATCH 1/2] clk: meson: Add vid_pll divider driver |
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Hi Neil,
On Fri, Jul 20, 2018 at 11:40 AM Neil Armstrong <narmstrong@baylibre.com> wrote: > > Add support the VID_PLL fully programmable divider used right after the > HDMI PLL clock source. It is used to achieve complex fractional division > with a programmble bitfield. I assume you have no other information that the S912 datasheet, pages 64 and 77 which describe the HHI_VID_PLL_CLK_DIV register?
more comments inline
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> > > --- > drivers/clk/meson/Makefile | 2 +- > drivers/clk/meson/clkc.h | 6 +++ > drivers/clk/meson/vid-pll-div.c | 90 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 97 insertions(+), 1 deletion(-) > create mode 100644 drivers/clk/meson/vid-pll-div.c > > diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile > index 72ec8c4..0234767 100644 > --- a/drivers/clk/meson/Makefile > +++ b/drivers/clk/meson/Makefile > @@ -2,7 +2,7 @@ > # Makefile for Meson specific clk > # > > -obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-mpll.o clk-phase.o > +obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-mpll.o clk-phase.o vid-pll-div.o > obj-$(CONFIG_COMMON_CLK_AMLOGIC_AUDIO) += clk-triphase.o sclk-div.o > obj-$(CONFIG_COMMON_CLK_MESON_AO) += meson-aoclk.o > obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o > diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h > index 6b96d55..9166605 100644 > --- a/drivers/clk/meson/clkc.h > +++ b/drivers/clk/meson/clkc.h > @@ -90,6 +90,11 @@ struct meson_clk_phase_data { > int meson_clk_degrees_from_val(unsigned int val, unsigned int width); > unsigned int meson_clk_degrees_to_val(int degrees, unsigned int width); > > +struct meson_vid_pll_div_data { > + struct parm val; > + struct parm sel; > +}; > + > #define MESON_GATE(_name, _reg, _bit) \ > struct clk_regmap _name = { \ > .data = &(struct clk_regmap_gate_data){ \ > @@ -112,5 +117,6 @@ extern const struct clk_ops meson_clk_cpu_ops; > extern const struct clk_ops meson_clk_mpll_ro_ops; > extern const struct clk_ops meson_clk_mpll_ops; > extern const struct clk_ops meson_clk_phase_ops; > +extern const struct clk_ops meson_vid_pll_div_ro_ops; > > #endif /* __CLKC_H */ > diff --git a/drivers/clk/meson/vid-pll-div.c b/drivers/clk/meson/vid-pll-div.c > new file mode 100644 > index 0000000..5f267be > --- /dev/null > +++ b/drivers/clk/meson/vid-pll-div.c > @@ -0,0 +1,90 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2018 BayLibre, SAS. > + * Author: Neil Armstrong <narmstrong@baylibre.com> > + */ > + > +#include <linux/clk-provider.h> > +#include "clkc.h" > + > +static inline struct meson_vid_pll_div_data * > +meson_vid_pll_div_data(struct clk_regmap *clk) > +{ > + return (struct meson_vid_pll_div_data *)clk->data; > +} > + > +/* > + * This vid_pll divided is a fully programmable fractionnal divider to > + * achieve complex video clock rates. > + * > + * Here are provided the commonly used fraction values provided by Amlogic. > + */ > + > +struct vid_pll_div { > + unsigned int shift_val; > + unsigned int shift_sel; > + unsigned int frac_top; maybe call it divider?
> + unsigned int frac_bot; maybe call it multiplier?
> +}; > + > +#define VID_PLL_DIV(_val, _sel, _ft, _fb) \ > + { \ > + .shift_val = (_val), \ > + .shift_sel = (_sel), \ > + .frac_top = (_ft), \ > + .frac_bot = (_fb), \ > + } > + > +static const struct vid_pll_div vid_pll_div_table[] = { > + VID_PLL_DIV(0x0aaa, 0, 2, 1), /* 2/1 => /2 */ > + VID_PLL_DIV(0x5294, 2, 5, 2), /* 5/2 => /2.5 */ > + VID_PLL_DIV(0x0db6, 0, 3, 1), /* 3/1 => /3 */ > + VID_PLL_DIV(0x36cc, 1, 7, 2), /* 7/2 => /3.5 */ > + VID_PLL_DIV(0x6666, 2, 15, 4), /* 15/4 => /3.75 */ > + VID_PLL_DIV(0x0ccc, 4, 4, 1), /* 4/1 => /4 */ is the shift_sel (second parameter) correct here? the public S912 datasheet, page 77 states that CLK_SEL is only 2 bit wide (and "4" exceeds that)
> + VID_PLL_DIV(0x739c, 2, 5, 1), /* 5/1 => /5 */ > + VID_PLL_DIV(0x0e38, 0, 6, 1), /* 6/1 => /6 */ > + VID_PLL_DIV(0x0000, 3, 25, 4), /* 25/4 => /6.25 */ > + VID_PLL_DIV(0x3c78, 1, 7, 1), /* 7/1 => /7 */ > + VID_PLL_DIV(0x78f0, 2, 15, 2), /* 15/2 => /7.5 */ > + VID_PLL_DIV(0x0fc0, 0, 12, 1), /* 12/1 => /12 */ > + VID_PLL_DIV(0x3f80, 1, 14, 1), /* 14/1 => /14 */ > + VID_PLL_DIV(0x7f80, 2, 15, 1), /* 15/1 => /15 */ > +}; > + > +#define to_meson_vid_pll_div(_hw) container_of(_hw, struct meson_vid_pll_div, hw) > + > +const struct vid_pll_div *_get_table_val(unsigned int shift_val, > + unsigned int shift_sel) > +{ > + int i; > + > + for (i = 0 ; i < ARRAY_SIZE(vid_pll_div_table) ; ++i) { > + if (vid_pll_div_table[i].shift_val == shift_val && > + vid_pll_div_table[i].shift_sel == shift_sel) > + return &vid_pll_div_table[i]; > + } > + > + return NULL; > +} > + > +static unsigned long meson_vid_pll_div_recalc_rate(struct clk_hw *hw, > + unsigned long parent_rate) > +{ > + struct clk_regmap *clk = to_clk_regmap(hw); > + struct meson_vid_pll_div_data *pll_div = meson_vid_pll_div_data(clk); > + const struct vid_pll_div *div; > + > + div = _get_table_val(meson_parm_read(clk->map, &pll_div->val), > + meson_parm_read(clk->map, &pll_div->sel)); > + if (!div || !div->frac_top) { > + pr_info("%s: Invalid config value for vid_pll_div\n", __func__); > + return parent_rate; > + } > + > + return DIV_ROUND_UP_ULL(parent_rate * div->frac_bot, div->frac_top); with the rename above this would read: return DIV_ROUND_UP_ULL(parent_rate * div->multiplier, div->divider);
Regards Martin
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