[PATCH v4 4/6] acerhdf: Use bang-bang thermal governor

Peter Feuerer
2014-07-20T00:51:51Z

acerhdf has been doing an on-off fan control using hysteresis by
post-manipulating the outcome of thermal subsystem trip point handling.
This patch enables acerhdf to use the bang-bang governor, which is
intended for on-off controlled fans.

Cc: Andrew Morton <akpm@linux-foundation.org>
CC: Zhang Rui <rui.zhang@intel.com>
Cc: Andreas Mohr <andi@lisas.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Javi Merino <javi.merino@arm.com>
Signed-off-by: Peter Feuerer <peter@piie.net>
---
drivers/platform/x86/Kconfig | 2 +-
drivers/platform/x86/acerhdf.c | 36 +++++++++++++++++++++++++++++++-----
2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 172f26c..d89252a 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -38,7 +38,7 @@ config ACER_WMI

config ACERHDF
tristate "Acer Aspire One temperature and fan driver"
- depends on THERMAL && ACPI
+ depends on ACPI && THERMAL_GOV_BANG_BANG
---help---
This is a driver for Acer Aspire One netbooks. It allows to access
the temperature sensor and to control the fan.
diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
index 176edbd..e8c3111 100644
--- a/drivers/platform/x86/acerhdf.c
+++ b/drivers/platform/x86/acerhdf.c
@@ -50,7 +50,7 @@
*/
#undef START_IN_KERNEL_MODE

-#define DRV_VER "0.5.30"
+#define DRV_VER "0.7.0"

/*
* According to the Atom N270 datasheet,
@@ -259,6 +259,14 @@ static const struct bios_settings_t bios_tbl[] = {

static const struct bios_settings_t *bios_cfg __read_mostly;

+/*
+ * this struct is used to instruct thermal layer to use bang_bang instead of
+ * default governor for acerhdf
+ */
+static struct thermal_zone_params acerhdf_zone_params = {
+ .governor_name = "bang_bang",
+};
+
static int acerhdf_get_temp(int *temp)
{
u8 read_temp;
@@ -440,6 +448,17 @@ static int acerhdf_get_trip_type(struct thermal_zone_device *thermal, int trip,
return 0;
}

+static int acerhdf_get_trip_hyst(struct thermal_zone_device *thermal, int trip,
+ unsigned long *temp)
+{
+ if (trip != 0)
+ return -EINVAL;
+
+ *temp = fanon - fanoff;
+
+ return 0;
+}
+
static int acerhdf_get_trip_temp(struct thermal_zone_device *thermal, int trip,
unsigned long *temp)
{
@@ -464,6 +483,7 @@ static struct thermal_zone_device_ops acerhdf_dev_ops = {
.get_mode = acerhdf_get_mode,
.set_mode = acerhdf_set_mode,
.get_trip_type = acerhdf_get_trip_type,
+ .get_trip_hyst = acerhdf_get_trip_hyst,
.get_trip_temp = acerhdf_get_trip_temp,
.get_crit_temp = acerhdf_get_crit_temp,
};
@@ -516,9 +536,7 @@ static int acerhdf_set_cur_state(struct thermal_cooling_device *cdev,
}

if (state == 0) {
- /* turn fan off only if below fanoff temperature */
- if ((cur_state == ACERHDF_FAN_AUTO) &&
- (cur_temp < fanoff))
+ if (cur_state == ACERHDF_FAN_AUTO)
acerhdf_change_fanstate(ACERHDF_FAN_OFF);
} else {
if (cur_state == ACERHDF_FAN_OFF)
@@ -697,11 +715,19 @@ static int acerhdf_register_thermal(void)
return -EINVAL;

thz_dev = thermal_zone_device_register("acerhdf", 1, 0, NULL,
- &acerhdf_dev_ops, NULL, 0,
+ &acerhdf_dev_ops,
+ &acerhdf_zone_params, 0,
(kernelmode) ? interval*1000 : 0);
if (IS_ERR(thz_dev))
return -EINVAL;

+ if (strcmp(thz_dev->governor->name,
+ acerhdf_zone_params.governor_name)) {
+ pr_err("Didn't get thermal governor %s, perhaps not compiled into thermal subsystem.\n",
+ acerhdf_zone_params.governor_name);
+ return -EINVAL;
+ }
+
return 0;
}

--
2.0.2