clk: meson: Add vid_pll divider driver

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.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Jerome Brunet <jbrunet@baylibre.com>
Link: http://lkml.kernel.org/r/1541516257-16157-2-git-send-email-narmstrong@baylibre.com

3 files changed, 98 insertions, 1 deletions

diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index 72ec8c40d848..0234767f6cfc 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 6b96d55c047d..91666055c75a 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 000000000000..b3370ea7beac
--- /dev/null
+++ b/drivers/clk/meson/vid-pll-div.c
@@ -0,0 +1,91 @@
+// 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 divider;
+        unsigned int multiplier;
+};
+
+#define VID_PLL_DIV(_val, _sel, _ft, _fb)                               \
+        {                                                               \
+                .shift_val = (_val),                                    \
+                .shift_sel = (_sel),                                    \
+                .divider = (_ft),                                       \
+                .multiplier = (_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, 0, 4, 1),   /* 4/1  => /4 */
+        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->divider) {
+                pr_info("%s: Invalid config value for vid_pll_div\n", __func__);
+                return parent_rate;
+        }
+
+        return DIV_ROUND_UP_ULL(parent_rate * div->multiplier, div->divider);
+}
+
+const struct clk_ops meson_vid_pll_div_ro_ops = {
+        .recalc_rate    = meson_vid_pll_div_recalc_rate,
+};