[RFC PATCH] clk: rockchip: rk3399: support pll setting automatically

[Xing Zheng]

From: Elaine Zhang <zhangqing@xxxxxxxxxxxxxx>

The goal is that we can configure the most suitable pll params automatically.

If setting freq is not supported in rockchip_pll_rate_table rk3399_pll_rates[],
we can set pll params automatically.

Signed-off-by: Elaine Zhang <zhangqing@xxxxxxxxxxxxxx>
Signed-off-by: Xing Zheng <zhengxing@xxxxxxxxxxxxxx>
---

 drivers/clk/rockchip/clk-pll.c |  213 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 200 insertions(+), 13 deletions(-)

diff --git a/drivers/clk/rockchip/clk-pll.c b/drivers/clk/rockchip/clk-pll.c
index 35994e8..08979f9 100644
--- a/drivers/clk/rockchip/clk-pll.c
+++ b/drivers/clk/rockchip/clk-pll.c
@@ -23,6 +23,7 @@
 #include <linux/clk-provider.h>
 #include <linux/regmap.h>
 #include <linux/clk.h>
+#include <linux/gcd.h>
 #include "clk.h"
 
 #define PLL_MODE_MASK		0x3
@@ -54,6 +55,200 @@ struct rockchip_clk_pll {
 #define to_rockchip_clk_pll_nb(nb) \
 			container_of(nb, struct rockchip_clk_pll, clk_nb)
 
+#define MHZ			(1000UL * 1000UL)
+#define KHZ			(1000UL)
+
+/* CLK_PLL_TYPE_RK3066_AUTO type ops */
+#define PLL_FREF_MIN		(269 * KHZ)
+#define PLL_FREF_MAX		(2200 * MHZ)
+
+#define PLL_FVCO_MIN		(440 * MHZ)
+#define PLL_FVCO_MAX		(2200 * MHZ)
+
+#define PLL_FOUT_MIN		(27500 * KHZ)
+#define PLL_FOUT_MAX		(2200 * MHZ)
+
+#define PLL_NF_MAX		(4096)
+#define PLL_NR_MAX		(64)
+#define PLL_NO_MAX		(16)
+
+/* CLK_PLL_TYPE_RK3036/3366/3399_AUTO type ops */
+#define MIN_FOUTVCO_FREQ	(800 * MHZ)
+#define MAX_FOUTVCO_FREQ	(2000 * MHZ)
+
+static struct rockchip_pll_rate_table auto_table;
+
+static struct rockchip_pll_rate_table *rk_pll_rate_table_get(void)
+{
+	return &auto_table;
+}
+
+static int rockchip_pll_clk_set_postdiv(unsigned long fout_hz,
+					u32 *postdiv1,
+					u32 *postdiv2,
+					u32 *foutvco)
+{
+	unsigned long freq;
+
+	if (fout_hz < MIN_FOUTVCO_FREQ) {
+		for (*postdiv1 = 1; *postdiv1 <= 7; (*postdiv1)++) {
+			for (*postdiv2 = 1; *postdiv2 <= 7; (*postdiv2)++) {
+				freq = fout_hz * (*postdiv1) * (*postdiv2);
+				if (freq >= MIN_FOUTVCO_FREQ &&
+				    freq <= MAX_FOUTVCO_FREQ) {
+					*foutvco = freq;
+					return 0;
+				}
+			}
+			pr_err("CANNOT FIND postdiv1/2 to make fout in range from 800M to 2000M,fout = %lu\n",
+			       fout_hz);
+		}
+	} else {
+		*postdiv1 = 1;
+		*postdiv2 = 1;
+	}
+	return 0;
+}
+
+static struct rockchip_pll_rate_table *
+rockchip_pll_clk_set_by_auto(struct rockchip_clk_pll *pll,
+			     unsigned long fin_hz,
+			     unsigned long fout_hz)
+{
+	struct rockchip_pll_rate_table *rate_table = rk_pll_rate_table_get();
+	/* FIXME set postdiv1/2 always 1*/
+	u32 foutvco = fout_hz;
+	u64 fin_64, frac_64;
+	u32 f_frac, postdiv1, postdiv2;
+	unsigned long clk_gcd = 0;
+
+	if (fin_hz == 0 || fout_hz == 0 || fout_hz == fin_hz)
+		return NULL;
+
+	rockchip_pll_clk_set_postdiv(fout_hz, &postdiv1, &postdiv2, &foutvco);
+	rate_table->postdiv1 = postdiv1;
+	rate_table->postdiv2 = postdiv2;
+	rate_table->dsmpd = 1;
+
+	if (fin_hz / MHZ * MHZ == fin_hz && fout_hz / MHZ * MHZ == fout_hz) {
+		fin_hz /= MHZ;
+		foutvco /= MHZ;
+		clk_gcd = gcd(fin_hz, foutvco);
+		rate_table->refdiv = fin_hz / clk_gcd;
+		rate_table->fbdiv = foutvco / clk_gcd;
+
+		rate_table->frac = 0;
+
+		pr_debug("fin = %lu, fout = %lu, clk_gcd = %lu, refdiv = %u, fbdiv = %u, postdiv1 = %u, postdiv2 = %u, frac = %u\n",
+			 fin_hz, fout_hz, clk_gcd, rate_table->refdiv,
+			 rate_table->fbdiv, rate_table->postdiv1,
+			 rate_table->postdiv2, rate_table->frac);
+	} else {
+		pr_debug("frac div running, fin_hz = %lu, fout_hz = %lu, fin_INT_mhz = %lu, fout_INT_mhz = %lu\n",
+			 fin_hz, fout_hz,
+			 fin_hz / MHZ * MHZ,
+			 fout_hz / MHZ * MHZ);
+		pr_debug("frac get postdiv1 = %u,  postdiv2 = %u, foutvco = %u\n",
+			 rate_table->postdiv1, rate_table->postdiv2, foutvco);
+		clk_gcd = gcd(fin_hz / MHZ, foutvco / MHZ);
+		rate_table->refdiv = fin_hz / MHZ / clk_gcd;
+		rate_table->fbdiv = foutvco / MHZ / clk_gcd;
+		pr_debug("frac get refdiv = %u,  fbdiv = %u\n",
+			 rate_table->refdiv, rate_table->fbdiv);
+
+		rate_table->frac = 0;
+
+		f_frac = (foutvco % MHZ);
+		fin_64 = fin_hz;
+		do_div(fin_64, (u64)rate_table->refdiv);
+		frac_64 = (u64)f_frac << 24;
+		do_div(frac_64, fin_64);
+		rate_table->frac = (u32)frac_64;
+		if (rate_table->frac > 0)
+			rate_table->dsmpd = 0;
+		pr_debug("frac = %x\n", rate_table->frac);
+	}
+	return rate_table;
+}
+
+static struct rockchip_pll_rate_table *
+rockchip_rk3066_pll_clk_set_by_auto(struct rockchip_clk_pll *pll,
+				    unsigned long fin_hz,
+				    unsigned long fout_hz)
+{
+	struct rockchip_pll_rate_table *rate_table = rk_pll_rate_table_get();
+	u32 nr, nf, no, nonr;
+	u32 nr_out, nf_out, no_out;
+	u32 n;
+	u32 numerator, denominator;
+	u64 fref, fvco, fout;
+	unsigned long clk_gcd = 0;
+
+	nr_out = PLL_NR_MAX + 1;
+	nf_out = 0;
+	no_out = 0;
+
+	if (fin_hz == 0 || fout_hz == 0 || fout_hz == fin_hz)
+		return NULL;
+
+	clk_gcd = gcd(fin_hz, fout_hz);
+
+	numerator = fout_hz / clk_gcd;
+	denominator = fin_hz / clk_gcd;
+
+	for (n = 1;; n++) {
+		nf = numerator * n;
+		nonr = denominator * n;
+		if (nf > PLL_NF_MAX || nonr > (PLL_NO_MAX * PLL_NR_MAX))
+			break;
+
+		for (no = 1; no <= PLL_NO_MAX; no++) {
+			if (!(no == 1 || !(no % 2)))
+				continue;
+
+			if (nonr % no)
+				continue;
+			nr = nonr / no;
+
+			if (nr > PLL_NR_MAX)
+				continue;
+
+			fref = fin_hz / nr;
+			if (fref < PLL_FREF_MIN || fref > PLL_FREF_MAX)
+				continue;
+
+			fvco = fref * nf;
+			if (fvco < PLL_FVCO_MIN || fvco > PLL_FVCO_MAX)
+				continue;
+
+			fout = fvco / no;
+			if (fout < PLL_FOUT_MIN || fout > PLL_FOUT_MAX)
+				continue;
+
+			/* select the best from all available PLL settings */
+			if ((no > no_out) ||
+			    ((no == no_out) && (nr < nr_out))) {
+				nr_out = nr;
+				nf_out = nf;
+				no_out = no;
+			}
+		}
+	}
+
+	/* output the best PLL setting */
+	if ((nr_out <= PLL_NR_MAX) && (no_out > 0)) {
+		if (rate_table->nr && rate_table->nf && rate_table->no) {
+			rate_table->nr = nr_out;
+			rate_table->nf = nf_out;
+			rate_table->no = no_out;
+		}
+	} else {
+		return NULL;
+	}
+
+	return rate_table;
+}
+
 static const struct rockchip_pll_rate_table *rockchip_get_pll_settings(
 			    struct rockchip_clk_pll *pll, unsigned long rate)
 {
@@ -65,24 +260,16 @@ static const struct rockchip_pll_rate_table *rockchip_get_pll_settings(
 			return &rate_table[i];
 	}
 
-	return NULL;
+	if (pll->type == pll_rk3066)
+		return rockchip_rk3066_pll_clk_set_by_auto(pll, 24 * MHZ, rate);
+	else
+		return rockchip_pll_clk_set_by_auto(pll, 24 * MHZ, rate);
 }
 
 static long rockchip_pll_round_rate(struct clk_hw *hw,
 			    unsigned long drate, unsigned long *prate)
 {
-	struct rockchip_clk_pll *pll = to_rockchip_clk_pll(hw);
-	const struct rockchip_pll_rate_table *rate_table = pll->rate_table;
-	int i;
-
-	/* Assumming rate_table is in descending order */
-	for (i = 0; i < pll->rate_count; i++) {
-		if (drate >= rate_table[i].rate)
-			return rate_table[i].rate;
-	}
-
-	/* return minimum supported value */
-	return rate_table[i - 1].rate;
+	return drate;
 }
 
 /*
-- 
1.7.9.5