clk: mxl: Add option to override gate clks

In MxL's LGM SoC, gate clocks can be controlled either from CGU clk driver
i.e. this driver or directly from power management driver/daemon. It is
dependent on the power policy/profile requirements of the end product.

To support such use cases, provide option to override gate clks enable/disable
by adding a flag GATE_CLK_HW which controls if these gate clks are controlled
by HW i.e. this driver or overridden in order to allow it to be controlled
by power profiles instead.

Reviewed-by: Yi xin Zhu <yzhu@maxlinear.com>
Signed-off-by: Rahul Tanwar <rtanwar@maxlinear.com>
Link: https://lore.kernel.org/r/bdc9c89317b5d338a6c4f1d49386b696e947a672.1665642720.git.rtanwar@maxlinear.com
[sboyd@kernel.org: Add braces on many line if-else]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/x86/clk-cgu.c

@@ -354,8 +354,22 @@ int lgm_clk_register_branches(struct lgm_clk_provider *ctx,
 			hw = lgm_clk_register_fixed_factor(ctx, list);
 			break;
 		case CLK_TYPE_GATE:
-			hw = lgm_clk_register_gate(ctx, list);
+			if (list->gate_flags & GATE_CLK_HW) {
+				hw = lgm_clk_register_gate(ctx, list);
+			} else {
+				/*
+				 * GATE_CLKs can be controlled either from
+				 * CGU clk driver i.e. this driver or directly
+				 * from power management driver/daemon. It is
+				 * dependent on the power policy/profile requirements
+				 * of the end product. To override control of gate
+				 * clks from this driver, provide NULL for this index
+				 * of gate clk provider.
+				 */
+				hw = NULL;
+			}
 			break;
+
 		default:
 			dev_err(ctx->dev, "invalid clk type\n");
 			return -EINVAL;

drivers/clk/x86/clk-cgu.h

@@ -197,6 +197,7 @@ struct lgm_clk_branch {
 /* clock flags definition */
 #define CLOCK_FLAG_VAL_INIT	BIT(16)
 #define MUX_CLK_SW		BIT(17)
+#define GATE_CLK_HW		BIT(18)
 
 #define LGM_MUX(_id, _name, _pdata, _f, _reg,		\
 		_shift, _width, _cf, _v)		\