diff options
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpio-ich.c | 21 |
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; |