clk: imx: composite-8m: Enable gate clk with mcore_booted

Bootloader might disable some CCM ROOT Slices. So if mcore_booted set with
display CCM ROOT disabled by Bootloader, kernel display BLK CTRL driver
imx8m_blk_ctrl_driver_init may hang the system because the BUS clk is
disabled.

Add back gate ops, but with disable doing nothing, then the CCM ROOT
will be enabled when used.

Fixes: bb7e897 ("clk: imx8m: check mcore_booted before register clk")
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20240607133347.3291040-2-peng.fan@oss.nxp.com
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>

Author: MrVan

drivers/clk/imx/clk-composite-8m.c

@@ -204,6 +204,34 @@ static const struct clk_ops imx8m_clk_composite_mux_ops = {
 	.determine_rate = imx8m_clk_composite_mux_determine_rate,
 };
 
+static int imx8m_clk_composite_gate_enable(struct clk_hw *hw)
+{
+	struct clk_gate *gate = to_clk_gate(hw);
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(gate->lock, flags);
+
+	val = readl(gate->reg);
+	val |= BIT(gate->bit_idx);
+	writel(val, gate->reg);
+
+	spin_unlock_irqrestore(gate->lock, flags);
+
+	return 0;
+}
+
+static void imx8m_clk_composite_gate_disable(struct clk_hw *hw)
+{
+	/* composite clk requires the disable hook */
+}
+
+static const struct clk_ops imx8m_clk_composite_gate_ops = {
+	.enable = imx8m_clk_composite_gate_enable,
+	.disable = imx8m_clk_composite_gate_disable,
+	.is_enabled = clk_gate_is_enabled,
+};
+
 struct clk_hw *__imx8m_clk_hw_composite(const char *name,
 					const char * const *parent_names,
 					int num_parents, void __iomem *reg,
@@ -217,6 +245,7 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name,
 	struct clk_mux *mux;
 	const struct clk_ops *divider_ops;
 	const struct clk_ops *mux_ops;
+	const struct clk_ops *gate_ops;
 
 	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 	if (!mux)
@@ -257,20 +286,22 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name,
 	div->flags = CLK_DIVIDER_ROUND_CLOSEST;
 
 	/* skip registering the gate ops if M4 is enabled */
-	if (!mcore_booted) {
-		gate = kzalloc(sizeof(*gate), GFP_KERNEL);
-		if (!gate)
-			goto free_div;
-
-		gate_hw = &gate->hw;
-		gate->reg = reg;
-		gate->bit_idx = PCG_CGC_SHIFT;
-		gate->lock = &imx_ccm_lock;
-	}
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		goto free_div;
+
+	gate_hw = &gate->hw;
+	gate->reg = reg;
+	gate->bit_idx = PCG_CGC_SHIFT;
+	gate->lock = &imx_ccm_lock;
+	if (!mcore_booted)
+		gate_ops = &clk_gate_ops;
+	else
+		gate_ops = &imx8m_clk_composite_gate_ops;
 
 	hw = clk_hw_register_composite(NULL, name, parent_names, num_parents,
 			mux_hw, mux_ops, div_hw,
-			divider_ops, gate_hw, &clk_gate_ops, flags);
+			divider_ops, gate_hw, gate_ops, flags);
 	if (IS_ERR(hw))
 		goto free_gate;