ideapad: add ACPI helpers

There are two methods under VPC2004 which is used to access VDAT/VCMD of EC
register. Add helpers for read and write these two registers.

And add read_method_int for reading the return value from ACPI methods which
requires no parameter.

Signed-off-by: Ike Panhc <ike.pan@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 109 insertions, 0 deletions

diff --git a/drivers/platform/x86/ideapad_acpi.c b/drivers/platform/x86/ideapad_acpi.c
index 798496353e8c..c87693c7dde0 100644
--- a/drivers/platform/x86/ideapad_acpi.c
+++ b/drivers/platform/x86/ideapad_acpi.c
@@ -49,6 +49,115 @@ static struct {
         { "ideapad_killsw",     RFKILL_TYPE_WLAN }
 };
 
+/*
+ * ACPI Helpers
+ */
+#define IDEAPAD_EC_TIMEOUT (100) /* in ms */
+
+static int read_method_int(acpi_handle handle, const char *method, int *val)
+{
+        acpi_status status;
+        unsigned long long result;
+
+        status = acpi_evaluate_integer(handle, (char *)method, NULL, &result);
+        if (ACPI_FAILURE(status)) {
+                *val = -1;
+                return -1;
+        } else {
+                *val = result;
+                return 0;
+        }
+}
+
+static int method_vpcr(acpi_handle handle, int cmd, int *ret)
+{
+        acpi_status status;
+        unsigned long long result;
+        struct acpi_object_list params;
+        union acpi_object in_obj;
+
+        params.count = 1;
+        params.pointer = &in_obj;
+        in_obj.type = ACPI_TYPE_INTEGER;
+        in_obj.integer.value = cmd;
+
+        status = acpi_evaluate_integer(handle, "VPCR", &params, &result);
+
+        if (ACPI_FAILURE(status)) {
+                *ret = -1;
+                return -1;
+        } else {
+                *ret = result;
+                return 0;
+        }
+}
+
+static int method_vpcw(acpi_handle handle, int cmd, int data)
+{
+        struct acpi_object_list params;
+        union acpi_object in_obj[2];
+        acpi_status status;
+
+        params.count = 2;
+        params.pointer = in_obj;
+        in_obj[0].type = ACPI_TYPE_INTEGER;
+        in_obj[0].integer.value = cmd;
+        in_obj[1].type = ACPI_TYPE_INTEGER;
+        in_obj[1].integer.value = data;
+
+        status = acpi_evaluate_object(handle, "VPCW", &params, NULL);
+        if (status != AE_OK)
+                return -1;
+        return 0;
+}
+
+static int read_ec_data(acpi_handle handle, int cmd, unsigned long *data)
+{
+        int val;
+        unsigned long int end_jiffies;
+
+        if (method_vpcw(handle, 1, cmd))
+                return -1;
+
+        for (end_jiffies = jiffies+(HZ)*IDEAPAD_EC_TIMEOUT/1000+1;
+             time_before(jiffies, end_jiffies);) {
+                schedule();
+                if (method_vpcr(handle, 1, &val))
+                        return -1;
+                if (val == 0) {
+                        if (method_vpcr(handle, 0, &val))
+                                return -1;
+                        *data = val;
+                        return 0;
+                }
+        }
+        pr_err("timeout in read_ec_cmd\n");
+        return -1;
+}
+
+static int write_ec_cmd(acpi_handle handle, int cmd, unsigned long data)
+{
+        int val;
+        unsigned long int end_jiffies;
+
+        if (method_vpcw(handle, 0, data))
+                return -1;
+        if (method_vpcw(handle, 1, cmd))
+                return -1;
+
+        for (end_jiffies = jiffies+(HZ)*IDEAPAD_EC_TIMEOUT/1000+1;
+             time_before(jiffies, end_jiffies);) {
+                schedule();
+                if (method_vpcr(handle, 1, &val))
+                        return -1;
+                if (val == 0)
+                        return 0;
+        }
+        pr_err("timeout in write_ec_cmd\n");
+        return -1;
+}
+/* the above is ACPI helpers */
+
 static int ideapad_dev_exists(int device)
 {
         acpi_status status;