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path: root/drivers/i2c/busses/i2c-designware-platdrv.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-designware-platdrv.c')
-rw-r--r--drivers/i2c/busses/i2c-designware-platdrv.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index d0bdac0498ce..f7439c556413 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -28,6 +28,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
+#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/errno.h>
@@ -53,6 +54,22 @@ static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
}
#ifdef CONFIG_ACPI
+/*
+ * The HCNT/LCNT information coming from ACPI should be the most accurate
+ * for given platform. However, some systems get it wrong. On such systems
+ * we get better results by calculating those based on the input clock.
+ */
+static const struct dmi_system_id dw_i2c_no_acpi_params[] = {
+ {
+ .ident = "Dell Inspiron 7348",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"),
+ },
+ },
+ { }
+};
+
static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
u16 *hcnt, u16 *lcnt, u32 *sda_hold)
{
@@ -60,6 +77,9 @@ static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
acpi_handle handle = ACPI_HANDLE(&pdev->dev);
union acpi_object *obj;
+ if (dmi_check_system(dw_i2c_no_acpi_params))
+ return;
+
if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
return;