[PATCH 1/2] i2c: designware: add High-speed mode support

[wangxfdu]

From: Xiang Wang <xiang.a.wang@xxxxxxxxx>

1. Add High-speed mode support in designware core
2. Add function i2c_dw_acpi_setup_speed to determine
the bus speed from ACPI table.

Signed-off-by: Xiang Wang <xiang.a.wang@xxxxxxxxx>
---
 drivers/i2c/busses/i2c-designware-core.c | 88 ++++++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-designware-core.h | 11 ++++
 2 files changed, 99 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 6f19a33..f5c0d18 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -30,6 +30,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/acpi.h>
 #include "i2c-designware-core.h"
 
 /*
@@ -42,6 +43,8 @@
 #define DW_IC_SS_SCL_LCNT	0x18
 #define DW_IC_FS_SCL_HCNT	0x1c
 #define DW_IC_FS_SCL_LCNT	0x20
+#define DW_IC_HS_SCL_HCNT	0x24
+#define DW_IC_HS_SCL_LCNT	0x28
 #define DW_IC_INTR_STAT		0x2c
 #define DW_IC_INTR_MASK		0x30
 #define DW_IC_RAW_INTR_STAT	0x34
@@ -358,6 +361,16 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
 	dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
 
+	if (dev->hs_hcnt && dev->hs_lcnt) {
+		hcnt = dev->hs_hcnt;
+		lcnt = dev->hs_lcnt;
+
+		dw_writel(dev, hcnt, DW_IC_HS_SCL_HCNT);
+		dw_writel(dev, lcnt, DW_IC_HS_SCL_LCNT);
+		dev_dbg(dev->dev, "High-speed mode HCNT:LCNT = %d:%d\n",
+					hcnt, lcnt);
+	}
+
 	/* Configure SDA Hold Time if required */
 	if (dev->sda_hold_time) {
 		reg = dw_readl(dev, DW_IC_COMP_VERSION);
@@ -381,6 +394,81 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 }
 EXPORT_SYMBOL_GPL(i2c_dw_init);
 
+#ifdef CONFIG_ACPI
+static int i2c_dw_acpi_get_freq(struct acpi_resource *ares, void *data)
+{
+	struct dw_i2c_dev *i2c = data;
+	struct acpi_resource_i2c_serialbus *sb;
+	u32 i2c_speed;
+
+	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
+		sb = &ares->data.i2c_serial_bus;
+
+		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
+			i2c_speed = sb->connection_speed;
+			if (i2c_speed == DW_STD_SPEED) {
+				i2c->master_cfg &= ~DW_IC_SPEED_MASK;
+				i2c->master_cfg |= DW_IC_CON_SPEED_STD;
+			} else if (i2c_speed == DW_FAST_SPEED) {
+				i2c->master_cfg &= ~DW_IC_SPEED_MASK;
+				i2c->master_cfg |= DW_IC_CON_SPEED_FAST;
+			} else if (i2c_speed == DW_HIGH_SPEED) {
+				i2c->master_cfg &= ~DW_IC_SPEED_MASK;
+				i2c->master_cfg |= DW_IC_CON_SPEED_HIGH;
+			} else {
+				dev_err(i2c->dev, "unsupported speed: %d\n",
+					i2c_speed);
+			}
+
+			dev_dbg(i2c->dev, "i2c device speed from acpi = %d\n",
+					i2c_speed);
+		}
+	}
+
+	return 1;
+}
+
+static acpi_status acpi_i2c_find_device_speed(acpi_handle handle, u32 level,
+					void *data, void **return_value)
+{
+	struct dw_i2c_dev *i2c = data;
+	struct list_head resource_list;
+	struct acpi_device *adev;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+	if (acpi_bus_get_status(adev) || !adev->status.present)
+		return AE_OK;
+
+	INIT_LIST_HEAD(&resource_list);
+	acpi_dev_get_resources(adev, &resource_list,
+				i2c_dw_acpi_get_freq, i2c);
+	acpi_dev_free_resource_list(&resource_list);
+
+	return AE_OK;
+}
+
+void i2c_dw_acpi_setup_speed(struct device *pdev, struct dw_i2c_dev *dev)
+{
+	acpi_handle handle = ACPI_HANDLE(pdev);
+	acpi_status status;
+
+	if (handle == NULL)
+		return;
+
+	/* Find I2C adapter bus frequency */
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+				     acpi_i2c_find_device_speed, NULL,
+				     dev, NULL);
+	if (ACPI_FAILURE(status))
+		dev_warn(pdev, "failed to get I2C bus freq\n");
+}
+
+#else
+void i2c_dw_acpi_setup_speed(struct device *pdev, struct dw_i2c_dev *dev) {}
+#endif
+EXPORT_SYMBOL_GPL(i2c_dw_acpi_setup_speed);
+
 /*
  * Waiting for bus not busy
  */
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 9630222..16f53d8 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -24,12 +24,17 @@
 
 
 #define DW_IC_CON_MASTER		0x1
+#define DW_IC_SPEED_MASK		0x6
 #define DW_IC_CON_SPEED_STD		0x2
 #define DW_IC_CON_SPEED_FAST		0x4
+#define DW_IC_CON_SPEED_HIGH		0x6
 #define DW_IC_CON_10BITADDR_MASTER	0x10
 #define DW_IC_CON_RESTART_EN		0x20
 #define DW_IC_CON_SLAVE_DISABLE		0x40
 
+#define DW_STD_SPEED	100000
+#define DW_FAST_SPEED	400000
+#define DW_HIGH_SPEED	3400000
 
 /**
  * struct dw_i2c_dev - private i2c-designware data
@@ -61,6 +66,8 @@
  * @ss_lcnt: standard speed LCNT value
  * @fs_hcnt: fast speed HCNT value
  * @fs_lcnt: fast speed LCNT value
+ * @hs_hcnt: high speed HCNT value
+ * @hs_lcnt: high speed LCNT value
  * @acquire_lock: function to acquire a hardware lock on the bus
  * @release_lock: function to release a hardware lock on the bus
  * @pm_runtime_disabled: true if pm runtime is disabled
@@ -104,6 +111,8 @@ struct dw_i2c_dev {
 	u16			ss_lcnt;
 	u16			fs_hcnt;
 	u16			fs_lcnt;
+	u16			hs_hcnt;
+	u16			hs_lcnt;
 	int			(*acquire_lock)(struct dw_i2c_dev *dev);
 	void			(*release_lock)(struct dw_i2c_dev *dev);
 	bool			pm_runtime_disabled;
@@ -114,6 +123,8 @@ struct dw_i2c_dev {
 
 extern u32 dw_readl(struct dw_i2c_dev *dev, int offset);
 extern void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset);
+extern void i2c_dw_acpi_setup_speed(struct device *pdev,
+		struct dw_i2c_dev *dev);
 extern int i2c_dw_init(struct dw_i2c_dev *dev);
 extern int i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 		int num);
-- 
2.5.3

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