[PATCH] clk: sunxi: Add CSI (camera's Sensors Interface) module clock driver for sun[457]i

[yassinjaffer@gmail.com]

From: Yassin Jaffer <yassinjaffer@gmail.com>

This patch adds a composite clock type consisting of
a clock gate, mux, configurable dividers, and a reset control.

Signed-off-by: Yassin Jaffer <yassinjaffer@gmail.com>
---
 Documentation/devicetree/bindings/clock/sunxi.txt |   1 +
 drivers/clk/sunxi/Makefile                        |   1 +
 drivers/clk/sunxi/clk-a10-csi.c                   | 188 ++++++++++++++++++++++
 3 files changed, 190 insertions(+)
 create mode 100644 drivers/clk/sunxi/clk-a10-csi.c

diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
index e59f57b..c3826f7 100644
--- a/Documentation/devicetree/bindings/clock/sunxi.txt
+++ b/Documentation/devicetree/bindings/clock/sunxi.txt
@@ -77,6 +77,7 @@ Required properties:
 	"allwinner,sun9i-a80-usb-mod-clk" - for usb gates + resets on A80
 	"allwinner,sun9i-a80-usb-phy-clk" - for usb phy gates + resets on A80
 	"allwinner,sun4i-a10-ve-clk" - for the Video Engine clock
+	"allwinner,sun4i-a10-csi-clk" - for the CSI module
 
 Required properties for all clocks:
 - reg : shall be the control register address for the clock.
diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
index 3fd7901..42ce752 100644
--- a/drivers/clk/sunxi/Makefile
+++ b/drivers/clk/sunxi/Makefile
@@ -7,6 +7,7 @@ obj-y += clk-a10-codec.o
 obj-y += clk-a10-hosc.o
 obj-y += clk-a10-mod1.o
 obj-y += clk-a10-pll2.o
+obj-y += clk-a10-csi.o
 obj-y += clk-a10-ve.o
 obj-y += clk-a20-gmac.o
 obj-y += clk-mod0.o
diff --git a/drivers/clk/sunxi/clk-a10-csi.c b/drivers/clk/sunxi/clk-a10-csi.c
new file mode 100644
index 0000000..f17d206
--- /dev/null
+++ b/drivers/clk/sunxi/clk-a10-csi.c
@@ -0,0 +1,188 @@
+/*
+ * Copyright 2016 Yassin Jaffer
+ *
+ * Yassin Jaffer <yassinjaffer@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/of_address.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+static DEFINE_SPINLOCK(sun4i_csi_lock);
+
+#define SUN4I_CSI_PARENTS       5
+#define SUN4I_CSI_GATE_BIT      31
+#define SUN4I_CSI_RESET_BIT     30
+#define SUN4I_CSI_MUX_SHIFT     24
+#define SUN4I_CSI_DIV_WIDTH     5
+#define SUN4I_CSI_DIV_SHIFT     0
+
+static u32 sun4i_csi_mux_table[SUN4I_CSI_PARENTS] = {
+	0x0,
+	0x1,
+	0x2,
+	0x5,
+	0x6,
+};
+
+struct csi_reset_data {
+	void __iomem			*reg;
+	spinlock_t			*lock; /* lock for reset handling */
+	struct reset_controller_dev	rcdev;
+};
+
+static int sun4i_csi_assert(struct reset_controller_dev *rcdev,
+			    unsigned long id)
+{
+	struct csi_reset_data *data = container_of(rcdev,
+						  struct csi_reset_data,
+						  rcdev);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(data->lock, flags);
+
+	reg = readl(data->reg);
+	writel(reg & ~BIT(SUN4I_CSI_RESET_BIT), data->reg);
+
+	spin_unlock_irqrestore(data->lock, flags);
+
+	return 0;
+}
+
+static int sun4i_csi_deassert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	struct csi_reset_data *data = container_of(rcdev,
+						  struct csi_reset_data,
+						  rcdev);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(data->lock, flags);
+
+	reg = readl(data->reg);
+	writel(reg | BIT(SUN4I_CSI_RESET_BIT), data->reg);
+
+	spin_unlock_irqrestore(data->lock, flags);
+
+	return 0;
+}
+
+static int sun4i_csi_of_xlate(struct reset_controller_dev *rcdev,
+			      const struct of_phandle_args *reset_spec)
+{
+	if (WARN_ON(reset_spec->args_count != 0))
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct reset_control_ops sun4i_csi_reset_ops = {
+	.assert		= sun4i_csi_assert,
+	.deassert	= sun4i_csi_deassert,
+};
+
+static void __init sun4i_csi_clk_setup(struct device_node *node)
+{
+	const char *parents[SUN4I_CSI_PARENTS];
+	const char *clk_name = node->name;
+	struct csi_reset_data *reset_data;
+	struct clk_divider *div;
+	struct clk_gate *gate;
+	struct clk_mux *mux;
+	void __iomem *reg;
+	struct clk *clk;
+	int i = 0;
+
+	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
+	if (IS_ERR(reg))
+		return;
+
+	of_property_read_string(node, "clock-output-names", &clk_name);
+
+	i = of_clk_parent_fill(node, parents, SUN4I_CSI_PARENTS);
+
+	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		goto err_unmap;
+
+	mux->reg = reg;
+	mux->shift = SUN4I_CSI_MUX_SHIFT;
+	mux->table = sun4i_csi_mux_table;
+	mux->lock = &sun4i_csi_lock;
+
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		goto err_free_mux;
+
+	gate->reg = reg;
+	gate->bit_idx = SUN4I_CSI_GATE_BIT;
+	gate->lock = &sun4i_csi_lock;
+
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		goto err_free_gate;
+
+	div->reg = reg;
+	div->shift = SUN4I_CSI_DIV_SHIFT;
+	div->width = SUN4I_CSI_DIV_WIDTH;
+	div->lock = &sun4i_csi_lock;
+
+	clk = clk_register_composite(NULL, clk_name,
+				     parents, i,
+				     &mux->hw, &clk_mux_ops,
+				     &div->hw, &clk_divider_ops,
+				     &gate->hw, &clk_gate_ops,
+				     CLK_SET_RATE_PARENT);
+	if (IS_ERR(clk))
+		goto err_free_div;
+
+	of_clk_add_provider(node, of_clk_src_simple_get, clk);
+
+	reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
+	if (!reset_data)
+		goto err_free_clk;
+
+	reset_data->reg = reg;
+	reset_data->lock = &sun4i_csi_lock;
+	reset_data->rcdev.nr_resets = 1;
+	reset_data->rcdev.ops = &sun4i_csi_reset_ops;
+	reset_data->rcdev.of_node = node;
+	reset_data->rcdev.of_xlate = sun4i_csi_of_xlate;
+	reset_data->rcdev.of_reset_n_cells = 0;
+
+	if (reset_controller_register(&reset_data->rcdev))
+		goto err_free_reset;
+
+	return;
+
+err_free_reset:
+	kfree(reset_data);
+err_free_clk:
+	clk_unregister(clk);
+err_free_div:
+	kfree(div);
+err_free_gate:
+	kfree(gate);
+err_free_mux:
+	kfree(mux);
+err_unmap:
+	iounmap(reg);
+}
+
+CLK_OF_DECLARE(sun4i_csi, "allwinner,sun4i-a10-csi-clk",
+	       sun4i_csi_clk_setup);
+
-- 
1.9.1