On Mon, Aug 5, 2013 at 11:59 PM, Fabian Vogt <fabian@xxxxxxxxxxxxxx> wrote: > From: Fabian Vogt <fabian@xxxxxxxxxxxxxx> > > This driver supports the GPIO controller found in LSI ZEVIO SoCs. > It has been successfully tested on a TI nspire CX calculator. > > Signed-off-by: Fabian Vogt <fabian@xxxxxxxxxxxxxx> Hi Fabian, sorry for taking so long for getting around to review this. > +++ b/Documentation/devicetree/bindings/gpio/gpio-zevio.txt I want an ACK from one of the DT bindings maintainers for this portion of the driver ideally. (It looks all right to me.) > +config GPIO_ZEVIO > + bool "LSI ZEVIO SoC memory mapped GPIOs" > + depends on ARCH_NSPIRE Can't this appear in some other SoC? It doesn't seem very arch-dependent in itself. I would rather have this depend on OF so any device-tree enabled SoC may use it, plus we get compile coverage by allmodconfig. > diff --git a/drivers/gpio/gpio-zevio.c b/drivers/gpio/gpio-zevio.c (...) > +/* > + * Memory layout: > + * This chip has four gpio sections, each controls 8 GPIOs. > + * Bit 0 in section 0 is GPIO 0, bit 2 in section 1 is GPIO 10. > + * Disclaimer: Reverse engineered! > + * For more information refer to: > + * > http://hackspire.unsads.com/wiki/index.php/Memory-mapped_I/O_ports#90000000_-_General_Purpose_I.2FO_.28GPIO.29 Very ambitious. Impressive! > + * 0x00-0x3F: Section 0 > + * +0x00: Masked interrupt status (read-only) > + * +0x04: R: Interrupt status W: Reset interrupt status > + * +0x08: R: Interrupt mask W: Mask interrupt > + * +0x0C: W: Unmask interrupt (write-only) > + * +0x10: Direction: I/O=1/0 > + * +0x14: Output > + * +0x18: Input (read-only) > + * +0x20: R: Sticky interrupts W: Set sticky interrupt What is a sticky interrupt? Do you mean it is a level IRQ? Then it's edge triggered if zero and level triggered if "sticky" is set to 1, right? > +/* Functions for struct gpio_chip */ > +static int zevio_gpio_get(struct gpio_chip *chip, unsigned pin) > +{ > + struct zevio_gpio *controller = to_zevio_gpio(chip); > + > + /* Only reading allowed, so no spinlock needed */ > + uint16_t val = readw(ZEVIO_GPIO(controller, pin, INPUT)); Use just u16 please. uint16_t is some portable C type. Please replace uint16_t with u16 everywhere. > + > + return (val >> ZEVIO_GPIO_BIT(pin)) & 0x1; Use this construct: return !!(val & ZEVIO_GPIO_BIT(pin)); > +static void zevio_gpio_set(struct gpio_chip *chip, unsigned pin, int value) > +{ > + struct zevio_gpio *controller = to_zevio_gpio(chip); > + uint16_t val; > + > + spin_lock(&controller->lock); > + val = readw(ZEVIO_GPIO(controller, pin, OUTPUT)); > + if (value) > + val |= 1<<ZEVIO_GPIO_BIT(pin); I usually do this: #include <linux/bitops.h> val |= BIT(ZEVIO_GPIO_BIT(pin)); > + else > + val &= ~(1<<ZEVIO_GPIO_BIT(pin)); Dito, sort of... > + > + writew(val, ZEVIO_GPIO(controller, pin, OUTPUT)); > + spin_unlock(&controller->lock); > +} > + > +static int zevio_gpio_direction_input(struct gpio_chip *chip, unsigned pin) > +{ > + struct zevio_gpio *controller = to_zevio_gpio(chip); > + uint16_t val; > + > + spin_lock(&controller->lock); > + > + val = readw(ZEVIO_GPIO(controller, pin, DIRECTION)); > + val |= 1<<ZEVIO_GPIO_BIT(pin); Same idea as above. > + writew(val, ZEVIO_GPIO(controller, pin, DIRECTION)); > + > + spin_unlock(&controller->lock); > + > + return 0; > +} > + > +static int zevio_gpio_direction_output(struct gpio_chip *chip, > + unsigned pin, int value) > +{ > + struct zevio_gpio *controller = to_zevio_gpio(chip); > + uint16_t val; > + > + spin_lock(&controller->lock); > + val = readw(ZEVIO_GPIO(controller, pin, OUTPUT)); > + if (value) > + val |= 1<<ZEVIO_GPIO_BIT(pin); > + else > + val &= ~(1<<ZEVIO_GPIO_BIT(pin)); And here too. > + > + writew(val, ZEVIO_GPIO(controller, pin, OUTPUT)); > + val = readw(ZEVIO_GPIO(controller, pin, DIRECTION)); > + val &= ~(1<<ZEVIO_GPIO_BIT(pin)); > + writew(val, ZEVIO_GPIO(controller, pin, DIRECTION)); And here. > + > + spin_unlock(&controller->lock); > + > + return 0; > +} > + > +static int zevio_gpio_to_irq(struct gpio_chip *chip, unsigned pin) > +{ > + /* Not implemented due to weird lockups */ > + return -ENXIO; Hm. I guess this should be marked TODO: or something. So when you figure this out you also add an irqchip. The way this looks I was thinking it could use the drivers/gpio/gpio-generic.c driver, but maybe not? Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
