clk: rockchip: Add PLL flag ROCKCHIP_PLL_FIXED_MODE

RK3528 comes with a new PLL variant: its "PPLL", which mainly generates
clocks for the PCIe controller, operates in normal mode only. Let's
describe it with flag ROCKCHIP_PLL_FIXED_MODE and handle it in code.

Signed-off-by: Yao Zi <ziyao@disroot.org>
Link: https://lore.kernel.org/r/20250217061142.38480-7-ziyao@disroot.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Author: ziyao233

drivers/clk/rockchip/clk-pll.c

@@ -204,10 +204,12 @@ static int rockchip_rk3036_pll_set_params(struct rockchip_clk_pll *pll,
 	rockchip_rk3036_pll_get_params(pll, &cur);
 	cur.rate = 0;
 
-	cur_parent = pll_mux_ops->get_parent(&pll_mux->hw);
-	if (cur_parent == PLL_MODE_NORM) {
-		pll_mux_ops->set_parent(&pll_mux->hw, PLL_MODE_SLOW);
-		rate_change_remuxed = 1;
+	if (!(pll->flags & ROCKCHIP_PLL_FIXED_MODE)) {
+		cur_parent = pll_mux_ops->get_parent(&pll_mux->hw);
+		if (cur_parent == PLL_MODE_NORM) {
+			pll_mux_ops->set_parent(&pll_mux->hw, PLL_MODE_SLOW);
+			rate_change_remuxed = 1;
+		}
 	}
 
 	/* update pll values */

drivers/clk/rockchip/clk.h

@@ -444,6 +444,7 @@ struct rockchip_pll_rate_table {
  * Flags:
  * ROCKCHIP_PLL_SYNC_RATE - check rate parameters to match against the
  *	rate_table parameters and ajust them if necessary.
+ * ROCKCHIP_PLL_FIXED_MODE - the pll operates in normal mode only
  */
 struct rockchip_pll_clock {
 	unsigned int		id;
@@ -461,6 +462,7 @@ struct rockchip_pll_clock {
 };
 
 #define ROCKCHIP_PLL_SYNC_RATE		BIT(0)
+#define ROCKCHIP_PLL_FIXED_MODE		BIT(1)
 
 #define PLL(_type, _id, _name, _pnames, _flags, _con, _mode, _mshift,	\
 		_lshift, _pflags, _rtable)				\