On Fri, Mar 26, 2021 at 2:05 PM Sander Vanheule <sander@xxxxxxxxxxxxx> wrote: > > Realtek MIPS SoCs (platform name Otto) have GPIO controllers with up to > 64 GPIOs, divided over two banks. Each bank has a set of registers for > 32 GPIOs, with support for edge-triggered interrupts. > > Each GPIO bank consists of four 8-bit GPIO ports (ABCD and EFGH). Most > registers pack one bit per GPIO, except for the IMR register, which > packs two bits per GPIO (AB-CD). > > Although the byte order is currently assumed to have port A..D at offset > 0x0..0x3, this has been observed to be reversed on other, Lexra-based, > SoCs (e.g. RTL8196E/97D/97F). > > Interrupt support is disabled for the fallback devicetree-compatible > 'realtek,otto-gpio'. This allows for quick support of GPIO banks in > which the byte order would be unknown. In this case, the port ordering > in the IMR registers may not match the reversed order in the other > registers (DCBA, and BA-DC or DC-BA). Thanks for the update! My comments below. ... > +config GPIO_REALTEK_OTTO > + bool "Realtek Otto GPIO support" Why not module? > + depends on MACH_REALTEK_RTL > + default MACH_REALTEK_RTL > + select GPIO_GENERIC > + select GPIOLIB_IRQCHIP > + help > + The GPIO controller on the Otto MIPS platform supports up to two > + banks of 32 GPIOs, with edge triggered interrupts. The 32 GPIOs > + are grouped in four 8-bit wide ports. When allowing module build, here you may add what will be the name of it. ... > +/* > + * Total register block size is 0x1C for four ports. > + * On the RTL8380/RLT8390 platforms port A, B, and C are implemented. D? > + * RTL8389 and RTL8328 implement a second bank with ports E, F, G, and H. > + * > + * Port information is stored with the first port at offset 0, followed by the > + * second, etc. Most registers store one bit per GPIO and should be read out in > + * reversed endian order. The two interrupt mask registers store two bits per > + * GPIO, and should be manipulated with swahw32, if required. > + */ ... > +/* Seems like kernel doc format with missed ** header and properly formed summary and description. > + * Realtek GPIO driver data > + * Because the interrupt mask register (IMR) combines the function of > + * IRQ type selection and masking, two extra values are stored. > + * intr_mask is used to mask/unmask the interrupts for certain GPIO, > + * and intr_type is used to store the selected interrupt types. The > + * logical AND of these values is written to IMR on changes. > + * > + * @gc Associated gpio_chip instance > + * @base Base address of the register block > + * @lock Lock for accessing the IRQ registers and values > + * @intr_mask Mask for GPIO interrupts > + * @intr_type GPIO interrupt type selection > + */ > +struct realtek_gpio_ctrl { > + struct gpio_chip gc; > + void __iomem *base; > + raw_spinlock_t lock; > + u16 intr_mask[REALTEK_GPIO_PORTS_PER_BANK]; > + u16 intr_type[REALTEK_GPIO_PORTS_PER_BANK]; > +}; > + > +enum realtek_gpio_flags { > + GPIO_INTERRUPTS = BIT(0), > +}; ... > +static struct realtek_gpio_ctrl *irq_data_to_ctrl(struct irq_data *data) > +{ > + struct gpio_chip *gc = irq_data_get_irq_chip_data(data); > + > + return container_of(gc, struct realtek_gpio_ctrl, gc); > +} > +static unsigned int line_to_port(unsigned int line) > +{ > + return line / 8; > +} > + > +static unsigned int line_to_port_pin(unsigned int line) > +{ > + return line % 8; > +} These are useless. Just use them inline. ... > +static u8 read_u8_reg(void __iomem *reg, unsigned int port) > +{ > + return ioread8(reg + port); > +} > + > +static void write_u8_reg(void __iomem *reg, unsigned int port, u8 value) > +{ > + iowrite8(value, reg + port); > +} > + > +static void write_u16_reg(void __iomem *reg, unsigned int port, u16 value) > +{ > + iowrite16(value, reg + 2 * port); > +} What's the point? You better provide a controller structure as a parameter. Look into other drivers. There are plenty of examples how to provide IO accessors in smarter way. ... > +static void realtek_gpio_write_imr(struct realtek_gpio_ctrl *ctrl, > + unsigned int port, u16 irq_type, u16 irq_mask) > +{ > + write_u16_reg(ctrl->base + REALTEK_GPIO_REG_IMR, port, > + irq_type & irq_mask); Can be one line. > +} ... > + write_u8_reg(ctrl->base + REALTEK_GPIO_REG_ISR, line_to_port(line), > + BIT(line_to_port_pin(line))); line % 8 and line / 8 is much shorter. ANd then it becomes only one line. ... > +static int realtek_gpio_irq_set_type(struct irq_data *data, > + unsigned int flow_type) One line? ... > +static void realtek_gpio_irq_handler(struct irq_desc *desc) > +{ > + struct gpio_chip *gc = irq_desc_get_handler_data(desc); > + struct realtek_gpio_ctrl *ctrl = gpiochip_get_data(gc); > + struct irq_chip *irq_chip = irq_desc_get_chip(desc); > + void __iomem *reg_isr = ctrl->base + REALTEK_GPIO_REG_ISR; > + unsigned int lines_done; > + unsigned int port_pin_count; > + unsigned int port; > + unsigned int irq; > + int offset; > + unsigned long status; Rearrange them by swapping lines. > + chained_irq_enter(irq_chip, desc); > + > + for (lines_done = 0; lines_done < gc->ngpio; lines_done += 8) { > + port = line_to_port(lines_done); > + status = read_u8_reg(reg_isr, port); > + port_pin_count = min(gc->ngpio - lines_done, 8U); > + for_each_set_bit(offset, &status, port_pin_count) { > + irq = irq_find_mapping(gc->irq.domain, offset); > + generic_handle_irq(irq); > + write_u8_reg(reg_isr, port, BIT(offset)); Shouldn't it be in the ->irq_ack() callback? > + } > + } ... > +static const struct of_device_id realtek_gpio_of_match[] = { > + { .compatible = "realtek,otto-gpio" }, > + { > + .compatible = "realtek,rtl8380-gpio", > + .data = (void *)GPIO_INTERRUPTS Not sure why this flag is needed right now. Drop it completely for good. > + }, > + { > + .compatible = "realtek,rtl8390-gpio", > + .data = (void *)GPIO_INTERRUPTS Ditto. > + }, > + {} > +}; > + Extra blank line. > +MODULE_DEVICE_TABLE(of, realtek_gpio_of_match); ... > + iowrite32(GENMASK(31, 0), ctrl->base + REALTEK_GPIO_REG_ISR); This one perhaps needs a comment like "cleaning all IRQ states". Note, we have a proper callback for this, i.e. hw_init. Consider to use it. ... > +}; > + Extra blank line. > +builtin_platform_driver(realtek_gpio_driver); ... So, looking into the code, I think you may easily get rid of 30-50 LOCs. So, expecting <= 300 LOCs in v5. -- With Best Regards, Andy Shevchenko