[RFC 04/11] clk: imx: Add gate shared for i.MX8MP audiomix

[Abel Vesa]

The newer i.MX platform use some gates that have a shared control bit
between them.

Signed-off-by: Abel Vesa <abel.vesa@xxxxxxx>
---
 drivers/clk/imx/Makefile          |   2 +-
 drivers/clk/imx/clk-gate-shared.c | 111 ++++++++++++++++++++++++++++++++++++++
 drivers/clk/imx/clk.h             |   4 ++
 3 files changed, 116 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/imx/clk-gate-shared.c

diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index 928f874c..799a8ef 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -27,7 +27,7 @@ obj-$(CONFIG_MXC_CLK_SCU) += \
 
 obj-$(CONFIG_CLK_IMX8MM) += clk-imx8mm.o
 obj-$(CONFIG_CLK_IMX8MN) += clk-imx8mn.o
-obj-$(CONFIG_CLK_IMX8MP) += clk-imx8mp.o
+obj-$(CONFIG_CLK_IMX8MP) += clk-imx8mp.o clk-gate-shared.o
 obj-$(CONFIG_CLK_IMX8MQ) += clk-imx8mq.o
 obj-$(CONFIG_CLK_IMX8QXP) += clk-imx8qxp.o clk-imx8qxp-lpcg.o
 
diff --git a/drivers/clk/imx/clk-gate-shared.c b/drivers/clk/imx/clk-gate-shared.c
new file mode 100644
index 00000000..961a0e3
--- /dev/null
+++ b/drivers/clk/imx/clk-gate-shared.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include "clk.h"
+
+/**
+ * struct clk_gate_shared - i.MX specific gate clock having the gate flag
+ * shared with other gate clocks
+ */
+struct clk_gate_shared {
+	struct clk_gate	gate;
+	spinlock_t	*lock;
+	unsigned int	*share_count;
+};
+
+static int clk_gate_shared_enable(struct clk_hw *hw)
+{
+	struct clk_gate *gate = to_clk_gate(hw);
+	struct clk_gate_shared *shgate = container_of(gate,
+					struct clk_gate_shared, gate);
+	unsigned long flags = 0;
+	int ret = 0;
+
+	spin_lock_irqsave(shgate->lock, flags);
+
+	if (shgate->share_count && (*shgate->share_count)++ > 0)
+		goto out;
+
+	ret = clk_gate_ops.enable(hw);
+out:
+	spin_unlock_irqrestore(shgate->lock, flags);
+
+	return ret;
+}
+
+static void clk_gate_shared_disable(struct clk_hw *hw)
+{
+	struct clk_gate *gate = to_clk_gate(hw);
+	struct clk_gate_shared *shgate = container_of(gate,
+					struct clk_gate_shared, gate);
+	unsigned long flags = 0;
+
+	spin_lock_irqsave(shgate->lock, flags);
+
+	if (shgate->share_count) {
+		if (WARN_ON(*shgate->share_count == 0))
+			goto out;
+		else if (--(*shgate->share_count) > 0)
+			goto out;
+	}
+
+	clk_gate_ops.disable(hw);
+out:
+	spin_unlock_irqrestore(shgate->lock, flags);
+}
+
+static int clk_gate_shared_is_enabled(struct clk_hw *hw)
+{
+	return clk_gate_ops.is_enabled(hw);
+}
+
+static const struct clk_ops clk_gate_shared_ops = {
+	.enable = clk_gate_shared_enable,
+	.disable = clk_gate_shared_disable,
+	.is_enabled = clk_gate_shared_is_enabled,
+};
+
+struct clk_hw *imx_dev_clk_hw_gate_shared(struct device *dev, const char *name,
+				const char *parent, void __iomem *reg,
+				u8 shift, unsigned int *share_count)
+{
+	struct clk_gate_shared *shgate;
+	struct clk_gate *gate;
+	struct clk_hw *hw;
+	struct clk_init_data init;
+	int ret;
+
+	shgate = kzalloc(sizeof(*shgate), GFP_KERNEL);
+	if (!shgate)
+		return ERR_PTR(-ENOMEM);
+	gate = &shgate->gate;
+
+	init.name = name;
+	init.ops = &clk_gate_shared_ops;
+	init.flags = CLK_OPS_PARENT_ENABLE;
+	init.parent_names = parent ? &parent : NULL;
+	init.num_parents = parent ? 1 : 0;
+
+	gate->reg = reg;
+	gate->bit_idx = shift;
+	gate->lock = NULL;
+	gate->hw.init = &init;
+	shgate->lock = &imx_ccm_lock;
+	shgate->share_count = share_count;
+
+	hw = &gate->hw;
+
+	ret = clk_hw_register(NULL, hw);
+	if (ret) {
+		kfree(shgate);
+		return ERR_PTR(ret);
+	}
+
+	return hw;
+}
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index f074dd8..51d6c26 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -151,6 +151,10 @@ struct clk_hw *imx_clk_hw_sscg_pll(const char *name,
 				void __iomem *base,
 				unsigned long flags);
 
+struct clk_hw *imx_dev_clk_hw_gate_shared(struct device *dev, const char *name,
+				const char *parent, void __iomem *reg,
+				u8 shift, unsigned int *share_count);
+
 enum imx_pllv3_type {
 	IMX_PLLV3_GENERIC,
 	IMX_PLLV3_SYS,
-- 
2.7.4