mfd: ti_am335x_tscadc: Fix spin lock and reg_cache

Reg_cache variable is used to lock step enable register
from being accessed and written by both TSC and ADC
at the same time.
However, it isn't updated anywhere in the code at all.

If both TSC and ADC are used, eventually 1FFFF is always
written enabling all 16 steps uselessly causing a mess.

Patch fixes it by correcting the locks and updates the
variable by reading the step enable register

Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index cd74d594c563693fb8f288a5bbe524c904c0d399..9f3f07ad54bd77891c1b0b7c62e3aef166a0ceac 100644 (file)
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -57,10 +57,10 @@ EXPORT_SYMBOL_GPL(am335x_tsc_se_update);
 void am335x_tsc_se_set(struct ti_tscadc_dev *tsadc, u32 val)
 {
        spin_lock(&tsadc->reg_lock);
+       tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE);
        tsadc->reg_se_cache |= val;
-       spin_unlock(&tsadc->reg_lock);
-
        am335x_tsc_se_update(tsadc);
+       spin_unlock(&tsadc->reg_lock);
 }
 EXPORT_SYMBOL_GPL(am335x_tsc_se_set);