[PATCH v4 1/5] clk: sunxi: Add support for USB clock-register reset bits

[Hans de Goede]

The usb-clk register is special in that it not only contains clk gate bits,
but also has a few reset bits. This commit adds support for this by allowing
gates type sunxi clks to also register a reset controller.

Signed-off-by: Hans de Goede <hdego...@redhat.com>
---
 drivers/clk/sunxi/clk-sunxi.c | 71 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
index 64bda21..1e15e4c 100644
--- a/drivers/clk/sunxi/clk-sunxi.c
+++ b/drivers/clk/sunxi/clk-sunxi.c
@@ -18,6 +18,7 @@
 #include <linux/clkdev.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/reset-controller.h>
 
 #include "clk-factors.h"
 
@@ -838,6 +839,59 @@ static void __init sunxi_divider_clk_setup(struct 
device_node *node,
 
 
 /**
+ * sunxi_gates_reset... - reset bits in leaf gate clk registers handling
+ */
+
+struct gates_reset_data {
+       void __iomem                    *reg;
+       spinlock_t                      *lock;
+       struct reset_controller_dev     rcdev;
+};
+
+static int sunxi_gates_reset_assert(struct reset_controller_dev *rcdev,
+                             unsigned long id)
+{
+       struct gates_reset_data *data = container_of(rcdev,
+                                                    struct gates_reset_data,
+                                                    rcdev);
+       unsigned long flags;
+       u32 reg;
+
+       spin_lock_irqsave(data->lock, flags);
+
+       reg = readl(data->reg);
+       writel(reg & ~BIT(id), data->reg);
+
+       spin_unlock_irqrestore(data->lock, flags);
+
+       return 0;
+}
+
+static int sunxi_gates_reset_deassert(struct reset_controller_dev *rcdev,
+                               unsigned long id)
+{
+       struct gates_reset_data *data = container_of(rcdev,
+                                                    struct gates_reset_data,
+                                                    rcdev);
+       unsigned long flags;
+       u32 reg;
+
+       spin_lock_irqsave(data->lock, flags);
+
+       reg = readl(data->reg);
+       writel(reg | BIT(id), data->reg);
+
+       spin_unlock_irqrestore(data->lock, flags);
+
+       return 0;
+}
+
+static struct reset_control_ops sunxi_gates_reset_ops = {
+       .assert         = sunxi_gates_reset_assert,
+       .deassert       = sunxi_gates_reset_deassert,
+};
+
+/**
  * sunxi_gates_clk_setup() - Setup function for leaf gates on clocks
  */
 
@@ -845,6 +899,7 @@ static void __init sunxi_divider_clk_setup(struct 
device_node *node,
 
 struct gates_data {
        DECLARE_BITMAP(mask, SUNXI_GATES_MAX_SIZE);
+       u32 reset_mask;
 };
 
 static const struct gates_data sun4i_axi_gates_data __initconst = {
@@ -915,6 +970,7 @@ static void __init sunxi_gates_clk_setup(struct device_node 
*node,
                                         struct gates_data *data)
 {
        struct clk_onecell_data *clk_data;
+       struct gates_reset_data *reset_data;
        const char *clk_parent;
        const char *clk_name;
        void *reg;
@@ -958,6 +1014,21 @@ static void __init sunxi_gates_clk_setup(struct 
device_node *node,
        clk_data->clk_num = i;
 
        of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
+
+       /* Register a reset controler for gates with reset bits */
+       if (data->reset_mask == 0)
+               return;
+
+       reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
+       if (!reset_data)
+               return;
+
+       reset_data->reg = reg;
+       reset_data->lock = &clk_lock;
+       reset_data->rcdev.nr_resets = __fls(data->reset_mask) + 1;
+       reset_data->rcdev.ops = &sunxi_gates_reset_ops;
+       reset_data->rcdev.of_node = node;
+       reset_controller_register(&reset_data->rcdev);
 }
 
 
-- 
1.8.4.2

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