clk: aspeed: Add reset controller

There are some resets that are not associated with gates. These are
represented by a reset controller.

Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk-aspeed.c

@@ -8,6 +8,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <linux/reset-controller.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
@@ -267,6 +268,68 @@ static const struct clk_ops aspeed_clk_gate_ops = {
 	.is_enabled = aspeed_clk_is_enabled,
 };
 
+/**
+ * struct aspeed_reset - Aspeed reset controller
+ * @map: regmap to access the containing system controller
+ * @rcdev: reset controller device
+ */
+struct aspeed_reset {
+	struct regmap			*map;
+	struct reset_controller_dev	rcdev;
+};
+
+#define to_aspeed_reset(p) container_of((p), struct aspeed_reset, rcdev)
+
+static const u8 aspeed_resets[] = {
+	[ASPEED_RESET_XDMA]	= 25,
+	[ASPEED_RESET_MCTP]	= 24,
+	[ASPEED_RESET_ADC]	= 23,
+	[ASPEED_RESET_JTAG_MASTER] = 22,
+	[ASPEED_RESET_MIC]	= 18,
+	[ASPEED_RESET_PWM]	=  9,
+	[ASPEED_RESET_PCIVGA]	=  8,
+	[ASPEED_RESET_I2C]	=  2,
+	[ASPEED_RESET_AHB]	=  1,
+};
+
+static int aspeed_reset_deassert(struct reset_controller_dev *rcdev,
+				 unsigned long id)
+{
+	struct aspeed_reset *ar = to_aspeed_reset(rcdev);
+	u32 rst = BIT(aspeed_resets[id]);
+
+	return regmap_update_bits(ar->map, ASPEED_RESET_CTRL, rst, 0);
+}
+
+static int aspeed_reset_assert(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct aspeed_reset *ar = to_aspeed_reset(rcdev);
+	u32 rst = BIT(aspeed_resets[id]);
+
+	return regmap_update_bits(ar->map, ASPEED_RESET_CTRL, rst, rst);
+}
+
+static int aspeed_reset_status(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct aspeed_reset *ar = to_aspeed_reset(rcdev);
+	u32 val, rst = BIT(aspeed_resets[id]);
+	int ret;
+
+	ret = regmap_read(ar->map, ASPEED_RESET_CTRL, &val);
+	if (ret)
+		return ret;
+
+	return !!(val & rst);
+}
+
+static const struct reset_control_ops aspeed_reset_ops = {
+	.assert = aspeed_reset_assert,
+	.deassert = aspeed_reset_deassert,
+	.status = aspeed_reset_status,
+};
+
 static struct clk_hw *aspeed_clk_hw_register_gate(struct device *dev,
 		const char *name, const char *parent_name, unsigned long flags,
 		struct regmap *map, u8 clock_idx, u8 reset_idx,
@@ -308,17 +371,34 @@ static int aspeed_clk_probe(struct platform_device *pdev)
 {
 	const struct aspeed_clk_soc_data *soc_data;
 	struct device *dev = &pdev->dev;
+	struct aspeed_reset *ar;
 	struct regmap *map;
 	struct clk_hw *hw;
 	u32 val, rate;
-	int i;
+	int i, ret;
 
 	map = syscon_node_to_regmap(dev->of_node);
 	if (IS_ERR(map)) {
 		dev_err(dev, "no syscon regmap\n");
 		return PTR_ERR(map);
 	}
 
+	ar = devm_kzalloc(dev, sizeof(*ar), GFP_KERNEL);
+	if (!ar)
+		return -ENOMEM;
+
+	ar->map = map;
+	ar->rcdev.owner = THIS_MODULE;
+	ar->rcdev.nr_resets = ARRAY_SIZE(aspeed_resets);
+	ar->rcdev.ops = &aspeed_reset_ops;
+	ar->rcdev.of_node = dev->of_node;
+
+	ret = devm_reset_controller_register(dev, &ar->rcdev);
+	if (ret) {
+		dev_err(dev, "could not register reset controller\n");
+		return ret;
+	}
+
 	/* SoC generations share common layouts but have different divisors */
 	soc_data = of_device_get_match_data(dev);
 	if (!soc_data) {