[PATCH 1/2] clk: meson: Add vid_pll divider driver
From: martin.blumenstingl@googlemail.com (Martin Blumenstingl)
Date: 2018-07-20 19:17:45
Also in:
linux-amlogic, linux-clk, lkml
Hi Neil, On Fri, Jul 20, 2018 at 11:40 AM Neil Armstrong [off-list ref] 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
quoted hunk ↗ jump to hunk
Signed-off-by: Neil Armstrong <redacted> --- 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.cdiff --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.odiff --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