clk: meson: axg-audio: add g12a reset support

On the g12a, the register space dedicated to the audio clock also
provides some resets. Let the clock controller register a reset
provider as well for this SoC family.

the axg SoC family does not appear to provide this feature.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

drivers/clk/meson/axg-audio.c

@@ -12,6 +12,7 @@
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
+#include <linux/reset-controller.h>
 #include <linux/slab.h>
 
 #include "axg-audio.h"
@@ -918,6 +919,84 @@ static int devm_clk_get_enable(struct device *dev, char *id)
 	return 0;
 }
 
+struct axg_audio_reset_data {
+	struct reset_controller_dev rstc;
+	struct regmap *map;
+	unsigned int offset;
+};
+
+static void axg_audio_reset_reg_and_bit(struct axg_audio_reset_data *rst,
+					unsigned long id,
+					unsigned int *reg,
+					unsigned int *bit)
+{
+	unsigned int stride = regmap_get_reg_stride(rst->map);
+
+	*reg = (id / (stride * BITS_PER_BYTE)) * stride;
+	*reg += rst->offset;
+	*bit = id % (stride * BITS_PER_BYTE);
+}
+
+static int axg_audio_reset_update(struct reset_controller_dev *rcdev,
+				unsigned long id, bool assert)
+{
+	struct axg_audio_reset_data *rst =
+		container_of(rcdev, struct axg_audio_reset_data, rstc);
+	unsigned int offset, bit;
+
+	axg_audio_reset_reg_and_bit(rst, id, &offset, &bit);
+
+	regmap_update_bits(rst->map, offset, BIT(bit),
+			assert ? BIT(bit) : 0);
+
+	return 0;
+}
+
+static int axg_audio_reset_status(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	struct axg_audio_reset_data *rst =
+		container_of(rcdev, struct axg_audio_reset_data, rstc);
+	unsigned int val, offset, bit;
+
+	axg_audio_reset_reg_and_bit(rst, id, &offset, &bit);
+
+	regmap_read(rst->map, offset, &val);
+
+	return !!(val & BIT(bit));
+}
+
+static int axg_audio_reset_assert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	return axg_audio_reset_update(rcdev, id, true);
+}
+
+static int axg_audio_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	return axg_audio_reset_update(rcdev, id, false);
+}
+
+static int axg_audio_reset_toggle(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	int ret;
+
+	ret = axg_audio_reset_assert(rcdev, id);
+	if (ret)
+		return ret;
+
+	return axg_audio_reset_deassert(rcdev, id);
+}
+
+static const struct reset_control_ops axg_audio_rstc_ops = {
+	.assert = axg_audio_reset_assert,
+	.deassert = axg_audio_reset_deassert,
+	.reset = axg_audio_reset_toggle,
+	.status = axg_audio_reset_status,
+};
+
 static const struct regmap_config axg_audio_regmap_cfg = {
 	.reg_bits	= 32,
 	.val_bits	= 32,
@@ -927,12 +1006,15 @@ static const struct regmap_config axg_audio_regmap_cfg = {
 
 struct audioclk_data {
 	struct clk_hw_onecell_data *hw_onecell_data;
+	unsigned int reset_offset;
+	unsigned int reset_num;
 };
 
 static int axg_audio_clkc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	const struct audioclk_data *data;
+	struct axg_audio_reset_data *rst;
 	struct regmap *map;
 	struct resource *res;
 	void __iomem *regs;
@@ -984,8 +1066,27 @@ static int axg_audio_clkc_probe(struct platform_device *pdev)
 		}
 	}
 
-	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
 					data->hw_onecell_data);
+	if (ret)
+		return ret;
+
+	/* Stop here if there is no reset */
+	if (!data->reset_num)
+		return 0;
+
+	rst = devm_kzalloc(dev, sizeof(*rst), GFP_KERNEL);
+	if (!rst)
+		return -ENOMEM;
+
+	rst->map = map;
+	rst->offset = data->reset_offset;
+	rst->rstc.nr_resets = data->reset_num;
+	rst->rstc.ops = &axg_audio_rstc_ops;
+	rst->rstc.of_node = dev->of_node;
+	rst->rstc.owner = THIS_MODULE;
+
+	return devm_reset_controller_register(dev, &rst->rstc);
 }
 
 static const struct audioclk_data axg_audioclk_data = {
@@ -994,6 +1095,8 @@ static const struct audioclk_data axg_audioclk_data = {
 
 static const struct audioclk_data g12a_audioclk_data = {
 	.hw_onecell_data = &g12a_audio_hw_onecell_data,
+	.reset_offset = AUDIO_SW_RESET,
+	.reset_num = 26,
 };
 
 static const struct of_device_id clkc_match_table[] = {

drivers/clk/meson/axg-audio.h

@@ -22,6 +22,7 @@
 #define AUDIO_MCLK_F_CTRL	0x018
 #define AUDIO_MST_PAD_CTRL0	0x01c
 #define AUDIO_MST_PAD_CTRL1	0x020
+#define AUDIO_SW_RESET		0x024
 #define AUDIO_MST_A_SCLK_CTRL0	0x040
 #define AUDIO_MST_A_SCLK_CTRL1	0x044
 #define AUDIO_MST_B_SCLK_CTRL0	0x048