[PATCH] mfd: RK808: Add register caching
From: Lee Jones <hidden>
Date: 2014-09-17 16:10:05
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On Tue, 09 Sep 2014, 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 <dianders@chromium.org> --- drivers/mfd/rk808.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
Applied with Chris' Reviewed-by.
quoted hunk ↗ jump to hunk
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[] = {
-- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog