On 09/10/2014 07:06 AM, Doug Anderson wrote:
Let's define the voltatile registers (those that can't be cached) and enable caching. The rk808 is accessed almost constantly with cpufreq so this is really nice.As measured by ftrace: before this change: cpu0_set_target() => ~2200us after this change: cpu0_set_target() => ~500us Signed-off-by: Doug Anderson <diand...@chromium.org> --- drivers/mfd/rk808.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/drivers/mfd/rk808.c b/drivers/mfd/rk808.c index 0324422..bd02150 100644 --- a/drivers/mfd/rk808.c +++ b/drivers/mfd/rk808.c @@ -29,10 +29,40 @@ struct rk808_reg_data { int value; };+static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg)+{ + /* + * Notes: + * - Technically the ROUND_30s bit makes RTC_CTRL_REG volatile, but + * we don't use that feature. It's better to cache. + * - It's unlikely we care that RK808_DEVCTRL_REG is volatile since + * bits are cleared in case when we shutoff anyway, but better safe. + */ + + switch (reg) { + case RK808_SECONDS_REG ... RK808_WEEKS_REG: + case RK808_RTC_STATUS_REG: + case RK808_VB_MON_REG: + case RK808_THERMAL_REG: + case RK808_DCDC_UV_STS_REG: + case RK808_LDO_UV_STS_REG: + case RK808_DCDC_PG_REG: + case RK808_LDO_PG_REG: + case RK808_DEVCTRL_REG: + case RK808_INT_STS_REG1: + case RK808_INT_STS_REG2: + return true; + } + + return false; +} + static const struct regmap_config rk808_regmap_config = { .reg_bits = 8, .val_bits = 8, .max_register = RK808_IO_POL_REG, + .cache_type = REGCACHE_RBTREE, + .volatile_reg = rk808_is_volatile_reg, };static struct resource rtc_resources[] = {
Reviewed-by: Chris Zhong <z...@rock-chips.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
