diff options
Diffstat (limited to 'drivers/gpio/gpio-aspeed.c')
| -rw-r--r-- | drivers/gpio/gpio-aspeed.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/drivers/gpio/gpio-aspeed.c b/drivers/gpio/gpio-aspeed.c index c9baeeb7f0cc..a5ded50c6db0 100644 --- a/drivers/gpio/gpio-aspeed.c +++ b/drivers/gpio/gpio-aspeed.c @@ -59,18 +59,33 @@ struct aspeed_gpio { }; struct aspeed_gpio_bank { - uint16_t val_regs; + uint16_t val_regs; /* +0: Rd: read input value, Wr: set write latch + * +4: Rd/Wr: Direction (0=in, 1=out) + */ + uint16_t rdata_reg; /* Rd: read write latch, Wr: <none> */ uint16_t irq_regs; uint16_t debounce_regs; uint16_t tolerance_regs; const char names[4][3]; }; +/* + * Note: The "value" register returns the input value sampled on the + * line even when the GPIO is configured as an output. Since + * that input goes through synchronizers, writing, then reading + * back may not return the written value right away. + * + * The "rdata" register returns the content of the write latch + * and thus can be used to read back what was last written + * reliably. + */ + static const int debounce_timers[4] = { 0x00, 0x50, 0x54, 0x58 }; static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { { .val_regs = 0x0000, + .rdata_reg = 0x00c0, .irq_regs = 0x0008, .debounce_regs = 0x0040, .tolerance_regs = 0x001c, @@ -78,6 +93,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { }, { .val_regs = 0x0020, + .rdata_reg = 0x00c4, .irq_regs = 0x0028, .debounce_regs = 0x0048, .tolerance_regs = 0x003c, @@ -85,6 +101,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { }, { .val_regs = 0x0070, + .rdata_reg = 0x00c8, .irq_regs = 0x0098, .debounce_regs = 0x00b0, .tolerance_regs = 0x00ac, @@ -92,6 +109,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { }, { .val_regs = 0x0078, + .rdata_reg = 0x00cc, .irq_regs = 0x00e8, .debounce_regs = 0x0100, .tolerance_regs = 0x00fc, @@ -99,6 +117,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { }, { .val_regs = 0x0080, + .rdata_reg = 0x00d0, .irq_regs = 0x0118, .debounce_regs = 0x0130, .tolerance_regs = 0x012c, @@ -106,6 +125,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { }, { .val_regs = 0x0088, + .rdata_reg = 0x00d4, .irq_regs = 0x0148, .debounce_regs = 0x0160, .tolerance_regs = 0x015c, @@ -113,6 +133,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { }, { .val_regs = 0x01E0, + .rdata_reg = 0x00d8, .irq_regs = 0x0178, .debounce_regs = 0x0190, .tolerance_regs = 0x018c, @@ -120,6 +141,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { }, { .val_regs = 0x01e8, + .rdata_reg = 0x00dc, .irq_regs = 0x01a8, .debounce_regs = 0x01c0, .tolerance_regs = 0x01bc, @@ -129,6 +151,7 @@ static const struct aspeed_gpio_bank aspeed_gpio_banks[] = { enum aspeed_gpio_reg { reg_val, + reg_rdata, reg_dir, reg_irq_enable, reg_irq_type0, @@ -160,6 +183,8 @@ static inline void __iomem *bank_reg(struct aspeed_gpio *gpio, switch (reg) { case reg_val: return gpio->base + bank->val_regs + GPIO_VAL_VALUE; + case reg_rdata: + return gpio->base + bank->rdata_reg; case reg_dir: return gpio->base + bank->val_regs + GPIO_VAL_DIR; case reg_irq_enable: @@ -925,7 +950,7 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev) /* Populate it with initial values read from the HW */ for (i = 0; i < banks; i++) { - void __iomem *addr = bank_reg(gpio, &aspeed_gpio_banks[i], reg_val); + void __iomem *addr = bank_reg(gpio, &aspeed_gpio_banks[i], reg_rdata); gpio->dcache[i] = ioread32(addr); } |