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Subject[PATCH v4 6/7] soc: mediatek: mmsys: Add reset controller support
Date
Among other features the mmsys driver should implement a reset
controller to be able to reset different bits from their space.

Cc: Jitao Shi <jitao.shi@mediatek.com>
Suggested-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
---

Changes in v4:
- Remove unnused variable as pointed by Hsin-Yi.

drivers/soc/mediatek/mtk-mmsys.c | 68 ++++++++++++++++++++++++++++++++
drivers/soc/mediatek/mtk-mmsys.h | 2 +
2 files changed, 70 insertions(+)

diff --git a/drivers/soc/mediatek/mtk-mmsys.c b/drivers/soc/mediatek/mtk-mmsys.c
index d9bbb0721ff4..132302154349 100644
--- a/drivers/soc/mediatek/mtk-mmsys.c
+++ b/drivers/soc/mediatek/mtk-mmsys.c
@@ -4,10 +4,12 @@
* Author: James Liao <jamesjj.liao@mediatek.com>
*/

+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
#include <linux/soc/mediatek/mtk-mmsys.h>

#include "mtk-mmsys.h"
@@ -62,6 +64,8 @@ static const struct mtk_mmsys_driver_data mt8365_mmsys_driver_data = {
struct mtk_mmsys {
void __iomem *regs;
const struct mtk_mmsys_driver_data *data;
+ spinlock_t lock; /* protects mmsys_sw_rst_b reg */
+ struct reset_controller_dev rcdev;
};

void mtk_mmsys_ddp_connect(struct device *dev,
@@ -101,6 +105,58 @@ void mtk_mmsys_ddp_disconnect(struct device *dev,
}
EXPORT_SYMBOL_GPL(mtk_mmsys_ddp_disconnect);

+static int mtk_mmsys_reset_update(struct reset_controller_dev *rcdev, unsigned long id,
+ bool assert)
+{
+ struct mtk_mmsys *mmsys = container_of(rcdev, struct mtk_mmsys, rcdev);
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(&mmsys->lock, flags);
+
+ reg = readl_relaxed(mmsys->regs + MMSYS_SW0_RST_B);
+
+ if (assert)
+ reg &= ~BIT(id);
+ else
+ reg |= BIT(id);
+
+ writel_relaxed(reg, mmsys->regs + MMSYS_SW0_RST_B);
+
+ spin_unlock_irqrestore(&mmsys->lock, flags);
+
+ return 0;
+}
+
+static int mtk_mmsys_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ return mtk_mmsys_reset_update(rcdev, id, true);
+}
+
+static int mtk_mmsys_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ return mtk_mmsys_reset_update(rcdev, id, false);
+}
+
+static int mtk_mmsys_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ int ret;
+
+ ret = mtk_mmsys_reset_assert(rcdev, id);
+ if (ret)
+ return ret;
+
+ usleep_range(1000, 1100);
+
+ return mtk_mmsys_reset_deassert(rcdev, id);
+}
+
+static const struct reset_control_ops mtk_mmsys_reset_ops = {
+ .assert = mtk_mmsys_reset_assert,
+ .deassert = mtk_mmsys_reset_deassert,
+ .reset = mtk_mmsys_reset,
+};
+
static int mtk_mmsys_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -121,6 +177,18 @@ static int mtk_mmsys_probe(struct platform_device *pdev)
return ret;
}

+ spin_lock_init(&mmsys->lock);
+
+ mmsys->rcdev.owner = THIS_MODULE;
+ mmsys->rcdev.nr_resets = 32;
+ mmsys->rcdev.ops = &mtk_mmsys_reset_ops;
+ mmsys->rcdev.of_node = pdev->dev.of_node;
+ ret = devm_reset_controller_register(&pdev->dev, &mmsys->rcdev);
+ if (ret) {
+ dev_err(&pdev->dev, "Couldn't register mmsys reset controller: %d\n", ret);
+ return ret;
+ }
+
mmsys->data = of_device_get_match_data(&pdev->dev);
platform_set_drvdata(pdev, mmsys);

diff --git a/drivers/soc/mediatek/mtk-mmsys.h b/drivers/soc/mediatek/mtk-mmsys.h
index 9e2b81bd38db..8b0ed05117ea 100644
--- a/drivers/soc/mediatek/mtk-mmsys.h
+++ b/drivers/soc/mediatek/mtk-mmsys.h
@@ -78,6 +78,8 @@
#define DSI_SEL_IN_RDMA 0x1
#define DSI_SEL_IN_MASK 0x1

+#define MMSYS_SW0_RST_B 0x140
+
struct mtk_mmsys_routes {
u32 from_comp;
u32 to_comp;
--
2.30.2
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