clk: mediatek: Add MT8173 MMPLL change rate support

MT8173 MMPLL frequency settings are different from common PLLs.
It needs different post divider settings for some ranges of frequency.
This patch add support for MT8173 MMPLL frequency setting by adding
div-rate table to lookup suitable post divider setting under a
specified frequency.
Signed-off-by: James Liao <jamesjj.liao@mediatek.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/mediatek/clk-mt8173.c

@@ -795,8 +795,9 @@ CLK_OF_DECLARE(mtk_pericfg, "mediatek,mt8173-pericfg", mtk_pericfg_init);
 
 #define CON0_MT8173_RST_BAR	BIT(24)
 
-#define PLL(_id, _name, _reg, _pwr_reg, _en_mask, _flags, _pcwbits, _pd_reg, _pd_shift, \
-			_tuner_reg, _pcw_reg, _pcw_shift) { \
+#define PLL_B(_id, _name, _reg, _pwr_reg, _en_mask, _flags, _pcwbits,	\
+			_pd_reg, _pd_shift, _tuner_reg, _pcw_reg,	\
+			_pcw_shift, _div_table) {			\
 		.id = _id,						\
 		.name = _name,						\
 		.reg = _reg,						\
@@ -811,14 +812,31 @@ CLK_OF_DECLARE(mtk_pericfg, "mediatek,mt8173-pericfg", mtk_pericfg_init);
 		.tuner_reg = _tuner_reg,				\
 		.pcw_reg = _pcw_reg,					\
 		.pcw_shift = _pcw_shift,				\
+		.div_table = _div_table,				\
 	}
 
+#define PLL(_id, _name, _reg, _pwr_reg, _en_mask, _flags, _pcwbits,	\
+			_pd_reg, _pd_shift, _tuner_reg, _pcw_reg,	\
+			_pcw_shift)					\
+		PLL_B(_id, _name, _reg, _pwr_reg, _en_mask, _flags, _pcwbits, \
+			_pd_reg, _pd_shift, _tuner_reg, _pcw_reg, _pcw_shift, \
+			NULL)
+
+static const struct mtk_pll_div_table mmpll_div_table[] = {
+	{ .div = 0, .freq = MT8173_PLL_FMAX },
+	{ .div = 1, .freq = 1000000000 },
+	{ .div = 2, .freq = 702000000 },
+	{ .div = 3, .freq = 253500000 },
+	{ .div = 4, .freq = 126750000 },
+	{ } /* sentinel */
+};
+
 static const struct mtk_pll_data plls[] = {
 	PLL(CLK_APMIXED_ARMCA15PLL, "armca15pll", 0x200, 0x20c, 0x00000001, 0, 21, 0x204, 24, 0x0, 0x204, 0),
 	PLL(CLK_APMIXED_ARMCA7PLL, "armca7pll", 0x210, 0x21c, 0x00000001, 0, 21, 0x214, 24, 0x0, 0x214, 0),
 	PLL(CLK_APMIXED_MAINPLL, "mainpll", 0x220, 0x22c, 0xf0000101, HAVE_RST_BAR, 21, 0x220, 4, 0x0, 0x224, 0),
 	PLL(CLK_APMIXED_UNIVPLL, "univpll", 0x230, 0x23c, 0xfe000001, HAVE_RST_BAR, 7, 0x230, 4, 0x0, 0x234, 14),
-	PLL(CLK_APMIXED_MMPLL, "mmpll", 0x240, 0x24c, 0x00000001, 0, 21, 0x244, 24, 0x0, 0x244, 0),
+	PLL_B(CLK_APMIXED_MMPLL, "mmpll", 0x240, 0x24c, 0x00000001, 0, 21, 0x244, 24, 0x0, 0x244, 0, mmpll_div_table),
 	PLL(CLK_APMIXED_MSDCPLL, "msdcpll", 0x250, 0x25c, 0x00000001, 0, 21, 0x250, 4, 0x0, 0x254, 0),
 	PLL(CLK_APMIXED_VENCPLL, "vencpll", 0x260, 0x26c, 0x00000001, 0, 21, 0x260, 4, 0x0, 0x264, 0),
 	PLL(CLK_APMIXED_TVDPLL, "tvdpll", 0x270, 0x27c, 0x00000001, 0, 21, 0x270, 4, 0x0, 0x274, 0),

drivers/clk/mediatek/clk-mtk.h

@@ -134,6 +134,11 @@ struct clk_onecell_data *mtk_alloc_clk_data(unsigned int clk_num);
 
 #define HAVE_RST_BAR	BIT(0)
 
+struct mtk_pll_div_table {
+	u32 div;
+	unsigned long freq;
+};
+
 struct mtk_pll_data {
 	int id;
 	const char *name;
@@ -150,6 +155,7 @@ struct mtk_pll_data {
 	int pcwbits;
 	uint32_t pcw_reg;
 	int pcw_shift;
+	const struct mtk_pll_div_table *div_table;
 };
 
 void __init mtk_clk_register_plls(struct device_node *node,

drivers/clk/mediatek/clk-pll.c

@@ -138,16 +138,28 @@ static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
 		u32 freq, u32 fin)
 {
 	unsigned long fmin = 1000 * MHZ;
+	const struct mtk_pll_div_table *div_table = pll->data->div_table;
 	u64 _pcw;
 	u32 val;
 
 	if (freq > pll->data->fmax)
 		freq = pll->data->fmax;
 
-	for (val = 0; val < 5; val++) {
+	if (div_table) {
+		if (freq > div_table[0].freq)
+			freq = div_table[0].freq;
+
+		for (val = 0; div_table[val + 1].freq != 0; val++) {
+			if (freq > div_table[val + 1].freq)
+				break;
+		}
 		*postdiv = 1 << val;
-		if ((u64)freq * *postdiv >= fmin)
-			break;
+	} else {
+		for (val = 0; val < 5; val++) {
+			*postdiv = 1 << val;
+			if ((u64)freq * *postdiv >= fmin)
+				break;
+		}
 	}
 
 	/* _pcw = freq * postdiv / fin * 2^pcwfbits */