clk: mediatek: Add configurable pcwibits and fmin to mtk_pll_data

1. pcwibits: The integer bits of pcw for PLLs is extend to 8 bits,
   add a variable to indicate this change and
   backward-compatible.

2. fmin: The PLL frequency lower-bound is vary from 1GHz to
   1.5GHz, add a variable to indicate platform-dependent.
Signed-off-by: Owen Chen <owen.chen@mediatek.com>
Signed-off-by: Weiyi Lu <weiyi.lu@mediatek.com>
Acked-by: Sean Wang <sean.wang@kernel.org>
Reviewed-by: James Liao <jamesjj.liao@mediatek.com>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/mediatek/clk-mtk.h

@@ -227,8 +227,10 @@ struct mtk_pll_data {
 	unsigned int flags;
 	const struct clk_ops *ops;
 	u32 rst_bar_mask;
+	unsigned long fmin;
 	unsigned long fmax;
 	int pcwbits;
+	int pcwibits;
 	uint32_t pcw_reg;
 	int pcw_shift;
 	const struct mtk_pll_div_table *div_table;

drivers/clk/mediatek/clk-pll.c

@@ -32,6 +32,8 @@
 #define AUDPLL_TUNER_EN		BIT(31)
 
 #define POSTDIV_MASK		0x7
+
+/* default 7 bits integer, can be overridden with pcwibits. */
 #define INTEGER_BITS		7
 
 /*
@@ -68,12 +70,15 @@ static unsigned long __mtk_pll_recalc_rate(struct mtk_clk_pll *pll, u32 fin,
 		u32 pcw, int postdiv)
 {
 	int pcwbits = pll->data->pcwbits;
-	int pcwfbits;
+	int pcwfbits = 0;
+	int ibits;
 	u64 vco;
 	u8 c = 0;
 
 	/* The fractional part of the PLL divider. */
-	pcwfbits = pcwbits > INTEGER_BITS ? pcwbits - INTEGER_BITS : 0;
+	ibits = pll->data->pcwibits ? pll->data->pcwibits : INTEGER_BITS;
+	if (pcwbits > ibits)
+		pcwfbits = pcwbits - ibits;
 
 	vco = (u64)fin * pcw;
 
@@ -170,9 +175,10 @@ static void mtk_pll_set_rate_regs(struct mtk_clk_pll *pll, u32 pcw,
 static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
 		u32 freq, u32 fin)
 {
-	unsigned long fmin = 1000 * MHZ;
+	unsigned long fmin = pll->data->fmin ? pll->data->fmin : (1000 * MHZ);
 	const struct mtk_pll_div_table *div_table = pll->data->div_table;
 	u64 _pcw;
+	int ibits;
 	u32 val;
 
 	if (freq > pll->data->fmax)
@@ -196,7 +202,8 @@ static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
 	}
 
 	/* _pcw = freq * postdiv / fin * 2^pcwfbits */
-	_pcw = ((u64)freq << val) << (pll->data->pcwbits - INTEGER_BITS);
+	ibits = pll->data->pcwibits ? pll->data->pcwibits : INTEGER_BITS;
+	_pcw = ((u64)freq << val) << (pll->data->pcwbits - ibits);
 	do_div(_pcw, fin);
 
 	*pcw = (u32)_pcw;