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path: root/drivers/gpio/gpio-ich.c
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Diffstat (limited to 'drivers/gpio/gpio-ich.c')
-rw-r--r--drivers/gpio/gpio-ich.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/drivers/gpio/gpio-ich.c b/drivers/gpio/gpio-ich.c
index f3eb1c52f97b..bfef20f8ab48 100644
--- a/drivers/gpio/gpio-ich.c
+++ b/drivers/gpio/gpio-ich.c
@@ -78,6 +78,12 @@ struct ichx_desc {
/* Some chipsets have quirks, let these use their own request/get */
int (*request)(struct gpio_chip *chip, unsigned offset);
int (*get)(struct gpio_chip *chip, unsigned offset);
+
+ /*
+ * Some chipsets don't let reading output values on GPIO_LVL register
+ * this option allows driver caching written output values
+ */
+ bool use_outlvl_cache;
};
static struct {
@@ -89,6 +95,7 @@ static struct {
struct ichx_desc *desc; /* Pointer to chipset-specific description */
u32 orig_gpio_ctrl; /* Orig CTRL value, used to restore on exit */
u8 use_gpio; /* Which GPIO groups are usable */
+ int outlvl_cache[3]; /* cached output values */
} ichx_priv;
static int modparam_gpiobase = -1; /* dynamic */
@@ -106,14 +113,21 @@ static int ichx_write_bit(int reg, unsigned nr, int val, int verify)
spin_lock_irqsave(&ichx_priv.lock, flags);
- data = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
- ichx_priv.gpio_base);
+ if (reg == GPIO_LVL && ichx_priv.desc->use_outlvl_cache)
+ data = ichx_priv.outlvl_cache[reg_nr];
+ else
+ data = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
+ ichx_priv.gpio_base);
+
if (val)
data |= 1 << bit;
else
data &= ~(1 << bit);
ICHX_WRITE(data, ichx_priv.desc->regs[reg][reg_nr],
ichx_priv.gpio_base);
+ if (reg == GPIO_LVL && ichx_priv.desc->use_outlvl_cache)
+ ichx_priv.outlvl_cache[reg_nr] = data;
+
tmp = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
ichx_priv.gpio_base);
if (verify && data != tmp)
@@ -136,6 +150,9 @@ static int ichx_read_bit(int reg, unsigned nr)
data = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
ichx_priv.gpio_base);
+ if (reg == GPIO_LVL && ichx_priv.desc->use_outlvl_cache)
+ data = ichx_priv.outlvl_cache[reg_nr] | data;
+
spin_unlock_irqrestore(&ichx_priv.lock, flags);
return data & (1 << bit) ? 1 : 0;