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

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Date: Thu, 16 May 2024 17:08:31 +0200
From: Jerome Brunet <jbrunet@...libre.com>
To: Philipp Zabel <p.zabel@...gutronix.de>,
	Stephen Boyd <sboyd@...nel.org>,
	Neil Armstrong <neil.armstrong@...aro.org>
Cc: Jerome Brunet <jbrunet@...libre.com>,
	Jan Dakinevich <jan.dakinevich@...utedevices.com>,
	linux-kernel@...r.kernel.org,
	linux-amlogic@...ts.infradead.org,
	linux-clk@...r.kernel.org
Subject: [RFC PATCH 1/9] reset: amlogic: convert driver to regmap

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@...libre.com>
---
 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