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Date: Fri, 9 Oct 2015 16:47:05 +0800
From: wangxfdu@...il.com
To: wangxfdu@...il.com, xiang.a.wang@...el.com, wsa@...-dreams.de,
andriy.shevchenko@...ux.intel.com, jarkko.nikula@...ux.intel.com,
linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] i2c: designware: add High-speed mode support
From: Xiang Wang <xiang.a.wang@...el.com>
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@...el.com>
---
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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