[RFC PATCH 1/9] reset: amlogic: convert driver to regmap

[Jerome Brunet]

To allow using the same driver for the main reset controller and the
auxiliary ones embedded in the clock controllers, convert the
the Amlogic reset driver to regmap.

Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
---
 drivers/reset/reset-meson.c | 80 ++++++++++++++++++++-----------------
 1 file changed, 44 insertions(+), 36 deletions(-)

diff --git a/drivers/reset/reset-meson.c b/drivers/reset/reset-meson.c
index f78be97898bc..8f3d6e9df235 100644
--- a/drivers/reset/reset-meson.c
+++ b/drivers/reset/reset-meson.c
@@ -11,36 +11,44 @@
 #include <linux/of.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 
-#define BITS_PER_REG	32
-
 struct meson_reset_param {
 	int reg_count;
 	int level_offset;
 };
 
 struct meson_reset {
-	void __iomem *reg_base;
 	const struct meson_reset_param *param;
 	struct reset_controller_dev rcdev;
-	spinlock_t lock;
+	struct regmap *map;
 };
 
+static void meson_reset_offset_and_bit(struct meson_reset *data,
+				       unsigned long id,
+				       unsigned int *offset,
+				       unsigned int *bit)
+{
+	unsigned int stride = regmap_get_reg_stride(data->map);
+
+	*offset = (id / (stride * BITS_PER_BYTE)) * stride;
+	*bit = id % (stride * BITS_PER_BYTE);
+}
+
 static int meson_reset_reset(struct reset_controller_dev *rcdev,
-			      unsigned long id)
+			     unsigned long id)
 {
 	struct meson_reset *data =
 		container_of(rcdev, struct meson_reset, rcdev);
-	unsigned int bank = id / BITS_PER_REG;
-	unsigned int offset = id % BITS_PER_REG;
-	void __iomem *reg_addr = data->reg_base + (bank << 2);
+	unsigned int offset, bit;
 
-	writel(BIT(offset), reg_addr);
+	meson_reset_offset_and_bit(data, id, &offset, &bit);
 
-	return 0;
+	return regmap_update_bits(data->map, offset,
+				  BIT(bit), BIT(bit));
 }
 
 static int meson_reset_level(struct reset_controller_dev *rcdev,
@@ -48,25 +56,13 @@ static int meson_reset_level(struct reset_controller_dev *rcdev,
 {
 	struct meson_reset *data =
 		container_of(rcdev, struct meson_reset, rcdev);
-	unsigned int bank = id / BITS_PER_REG;
-	unsigned int offset = id % BITS_PER_REG;
-	void __iomem *reg_addr;
-	unsigned long flags;
-	u32 reg;
+	unsigned int offset, bit;
 
-	reg_addr = data->reg_base + data->param->level_offset + (bank << 2);
+	meson_reset_offset_and_bit(data, id, &offset, &bit);
+	offset += data->param->level_offset;
 
-	spin_lock_irqsave(&data->lock, flags);
-
-	reg = readl(reg_addr);
-	if (assert)
-		writel(reg & ~BIT(offset), reg_addr);
-	else
-		writel(reg | BIT(offset), reg_addr);
-
-	spin_unlock_irqrestore(&data->lock, flags);
-
-	return 0;
+	return regmap_update_bits(data->map, offset,
+				  BIT(bit), assert ? 0 : BIT(bit));
 }
 
 static int meson_reset_assert(struct reset_controller_dev *rcdev,
@@ -113,30 +109,42 @@ static const struct of_device_id meson_reset_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
 
+static const struct regmap_config regmap_config = {
+	.reg_bits   = 32,
+	.val_bits   = 32,
+	.reg_stride = 4,
+};
+
 static int meson_reset_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct meson_reset *data;
+	void __iomem *base;
 
-	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
-	data->reg_base = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(data->reg_base))
-		return PTR_ERR(data->reg_base);
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
 
-	data->param = of_device_get_match_data(&pdev->dev);
+	data->param = of_device_get_match_data(dev);
 	if (!data->param)
 		return -ENODEV;
 
-	spin_lock_init(&data->lock);
+	data->map = devm_regmap_init_mmio(dev, base, &regmap_config);
+	if (IS_ERR(data->map))
+		return dev_err_probe(dev, PTR_ERR(data->map),
+				     "can't init regmap mmio region\n");
 
 	data->rcdev.owner = THIS_MODULE;
-	data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;
+	data->rcdev.nr_resets = data->param->reg_count * BITS_PER_BYTE
+		* regmap_config.reg_stride;
 	data->rcdev.ops = &meson_reset_ops;
-	data->rcdev.of_node = pdev->dev.of_node;
+	data->rcdev.of_node = dev->of_node;
 
-	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
+	return devm_reset_controller_register(dev, &data->rcdev);
 }
 
 static struct platform_driver meson_reset_driver = {
-- 
2.43.0