ACPI: ibm-acpi: Use a enum to select the thermal sensor reading strategy

This patch consolidades all decisions regarding the strategy to be used to
read thinkpad thermal sensors into a single enum, and refactors the
thermal sensor reading code to use a much more readable (and easier to
extend) switch() construct, in a separate function.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>

1 files changed, 65 insertions, 25 deletions

diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index b81a95d2067c..baf9492f0a79 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -217,6 +217,17 @@ IBM_HANDLE(sfan, ec, "SFAN",	/* 570 */
 #define IBM_HKEY_HID    "IBM0068"
 #define IBM_PCI_HID     "PNP0A03"
 
+enum thermal_access_mode {
+        IBMACPI_THERMAL_NONE = 0,       /* No thermal support */
+        IBMACPI_THERMAL_ACPI_TMP07,     /* Use ACPI TMP0-7 */
+        IBMACPI_THERMAL_ACPI_UPDT,      /* Use ACPI TMP0-7 with UPDT */
+};
+
+#define IBMACPI_MAX_THERMAL_SENSORS 8   /* Max thermal sensors supported */
+struct ibm_thermal_sensors_struct {
+        s32 temp[IBMACPI_MAX_THERMAL_SENSORS];
+};
+
 struct ibm_struct {
         char *name;
         char param[32];
@@ -1275,50 +1286,79 @@ static int acpi_ec_write(int i, u8 v)
         return 1;
 }
 
-static int thermal_tmp_supported;
-static int thermal_updt_supported;
+static enum thermal_access_mode thermal_read_mode;
 
 static int thermal_init(void)
 {
-        /* temperatures not supported on 570, G4x, R30, R31, R32 */
-        thermal_tmp_supported = acpi_evalf(ec_handle, NULL, "TMP7", "qv");
-
-        /* 600e/x, 770e, 770x */
-        thermal_updt_supported = acpi_evalf(ec_handle, NULL, "UPDT", "qv");
+        if (acpi_evalf(ec_handle, NULL, "TMP7", "qv")) {
+                if (acpi_evalf(ec_handle, NULL, "UPDT", "qv")) {
+                        /* 600e/x, 770e, 770x */
+                        thermal_read_mode = IBMACPI_THERMAL_ACPI_UPDT;
+                } else {
+                        /* Standard ACPI TMPx access, max 8 sensors */
+                        thermal_read_mode = IBMACPI_THERMAL_ACPI_TMP07;
+                }
+        } else {
+                /* temperatures not supported on 570, G4x, R30, R31, R32 */
+                thermal_read_mode = IBMACPI_THERMAL_NONE;
+        }
 
         return 0;
 }
 
-static int thermal_read(char *p)
+static int thermal_get_sensors(struct ibm_thermal_sensors_struct *s)
 {
-        int len = 0;
+        int i, t;
+        char tmpi[] = "TMPi";
 
-        if (!thermal_tmp_supported)
-                len += sprintf(p + len, "temperatures:\tnot supported\n");
-        else {
-                int i, t;
-                char tmpi[] = "TMPi";
-                s8 tmp[8];
+        if (!s)
+                return -EINVAL;
 
-                if (thermal_updt_supported)
-                        if (!acpi_evalf(ec_handle, NULL, "UPDT", "v"))
+        switch (thermal_read_mode) {
+        case IBMACPI_THERMAL_ACPI_UPDT:
+                if (!acpi_evalf(ec_handle, NULL, "UPDT", "v"))
+                        return -EIO;
+                for (i = 0; i < 8; i++) {
+                        tmpi[3] = '0' + i;
+                        if (!acpi_evalf(ec_handle, &t, tmpi, "d"))
                                 return -EIO;
+                        s->temp[i] = (t - 2732) * 100;
+                }
+                return 8;
 
+        case IBMACPI_THERMAL_ACPI_TMP07:
                 for (i = 0; i < 8; i++) {
                         tmpi[3] = '0' + i;
                         if (!acpi_evalf(ec_handle, &t, tmpi, "d"))
                                 return -EIO;
-                        if (thermal_updt_supported)
-                                tmp[i] = (t - 2732 + 5) / 10;
-                        else
-                                tmp[i] = t;
+                        s->temp[i] = t * 1000;
                 }
+                return 8;
 
-                len += sprintf(p + len,
-                               "temperatures:\t%d %d %d %d %d %d %d %d\n",
-                               tmp[0], tmp[1], tmp[2], tmp[3],
-                               tmp[4], tmp[5], tmp[6], tmp[7]);
+        case IBMACPI_THERMAL_NONE:
+        default:
+                return 0;
         }
+}
+
+static int thermal_read(char *p)
+{
+        int len = 0;
+        int n, i;
+        struct ibm_thermal_sensors_struct t;
+
+        n = thermal_get_sensors(&t);
+        if (unlikely(n < 0))
+                return n;
+
+        len += sprintf(p + len, "temperatures:\t");
+
+        if (n > 0) {
+                for (i = 0; i < (n - 1); i++)
+                        len += sprintf(p + len, "%d ", t.temp[i] / 1000);
+                len += sprintf(p + len, "%d\n", t.temp[i] / 1000);
+        } else
+                len += sprintf(p + len, "not supported\n");
 
         return len;
 }