diff options
Diffstat (limited to 'drivers/gpio/gpio-tqmx86.c')
| -rw-r--r-- | drivers/gpio/gpio-tqmx86.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c new file mode 100644 index 000000000000..eedfc0e371e3 --- /dev/null +++ b/drivers/gpio/gpio-tqmx86.c @@ -0,0 +1,437 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * TQ-Systems TQMx86 PLD GPIO driver + * + * Based on vendor driver by: + * Vadim V.Vlasov <vvlasov@dev.rtsoft.ru> + */ + +#include <linux/bitmap.h> +#include <linux/bitops.h> +#include <linux/errno.h> +#include <linux/gpio/driver.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/seq_file.h> +#include <linux/slab.h> + +#define TQMX86_NGPIO 8 +#define TQMX86_NGPO 4 /* 0-3 - output */ +#define TQMX86_NGPI 4 /* 4-7 - input */ +#define TQMX86_DIR_INPUT_MASK 0xf0 /* 0-3 - output, 4-7 - input */ + +#define TQMX86_GPIODD 0 /* GPIO Data Direction Register */ +#define TQMX86_GPIOD 1 /* GPIO Data Register */ +#define TQMX86_GPIIC 3 /* GPI Interrupt Configuration Register */ +#define TQMX86_GPIIS 4 /* GPI Interrupt Status Register */ + +/* + * NONE, FALLING and RISING use the same bit patterns that can be programmed to + * the GPII register (after passing them to the TQMX86_GPII_ macros to shift + * them to the right position) + */ +#define TQMX86_INT_TRIG_NONE 0 +#define TQMX86_INT_TRIG_FALLING BIT(0) +#define TQMX86_INT_TRIG_RISING BIT(1) +#define TQMX86_INT_TRIG_BOTH (BIT(0) | BIT(1)) +#define TQMX86_INT_TRIG_MASK (BIT(0) | BIT(1)) +/* Stored in irq_type with GPII bits */ +#define TQMX86_INT_UNMASKED BIT(2) + +#define TQMX86_GPIIC_CONFIG(i, v) ((v) << (2 * (i))) +#define TQMX86_GPIIC_MASK(i) TQMX86_GPIIC_CONFIG(i, TQMX86_INT_TRIG_MASK) + +struct tqmx86_gpio_data { + struct gpio_chip chip; + void __iomem *io_base; + int irq; + /* Lock must be held for accessing output and irq_type fields */ + raw_spinlock_t spinlock; + DECLARE_BITMAP(output, TQMX86_NGPIO); + u8 irq_type[TQMX86_NGPIO]; +}; + +static u8 tqmx86_gpio_read(struct tqmx86_gpio_data *gd, unsigned int reg) +{ + return ioread8(gd->io_base + reg); +} + +static void tqmx86_gpio_write(struct tqmx86_gpio_data *gd, u8 val, + unsigned int reg) +{ + iowrite8(val, gd->io_base + reg); +} + +static void tqmx86_gpio_clrsetbits(struct tqmx86_gpio_data *gpio, + u8 clr, u8 set, unsigned int reg) + __must_hold(&gpio->spinlock) +{ + u8 val = tqmx86_gpio_read(gpio, reg); + + val &= ~clr; + val |= set; + + tqmx86_gpio_write(gpio, val, reg); +} + +static int tqmx86_gpio_get(struct gpio_chip *chip, unsigned int offset) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip); + + return !!(tqmx86_gpio_read(gpio, TQMX86_GPIOD) & BIT(offset)); +} + +static void _tqmx86_gpio_set(struct tqmx86_gpio_data *gpio, unsigned int offset, + int value) + __must_hold(&gpio->spinlock) +{ + __assign_bit(offset, gpio->output, value); + tqmx86_gpio_write(gpio, bitmap_get_value8(gpio->output, 0), TQMX86_GPIOD); +} + +static int tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset, + int value) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip); + + guard(raw_spinlock_irqsave)(&gpio->spinlock); + + _tqmx86_gpio_set(gpio, offset, value); + + return 0; +} + +static int tqmx86_gpio_direction_input(struct gpio_chip *chip, + unsigned int offset) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip); + + guard(raw_spinlock_irqsave)(&gpio->spinlock); + + tqmx86_gpio_clrsetbits(gpio, BIT(offset), 0, TQMX86_GPIODD); + + return 0; +} + +static int tqmx86_gpio_direction_output(struct gpio_chip *chip, + unsigned int offset, + int value) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip); + + guard(raw_spinlock_irqsave)(&gpio->spinlock); + + _tqmx86_gpio_set(gpio, offset, value); + tqmx86_gpio_clrsetbits(gpio, 0, BIT(offset), TQMX86_GPIODD); + + return 0; +} + +static int tqmx86_gpio_get_direction(struct gpio_chip *chip, + unsigned int offset) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip); + u8 val; + + val = tqmx86_gpio_read(gpio, TQMX86_GPIODD); + + if (val & BIT(offset)) + return GPIO_LINE_DIRECTION_OUT; + + return GPIO_LINE_DIRECTION_IN; +} + +static void tqmx86_gpio_irq_config(struct tqmx86_gpio_data *gpio, int hwirq) + __must_hold(&gpio->spinlock) +{ + u8 type = TQMX86_INT_TRIG_NONE; + int gpiic_irq = hwirq - TQMX86_NGPO; + + if (gpio->irq_type[hwirq] & TQMX86_INT_UNMASKED) { + type = gpio->irq_type[hwirq] & TQMX86_INT_TRIG_MASK; + + if (type == TQMX86_INT_TRIG_BOTH) + type = tqmx86_gpio_get(&gpio->chip, hwirq) + ? TQMX86_INT_TRIG_FALLING + : TQMX86_INT_TRIG_RISING; + } + + tqmx86_gpio_clrsetbits(gpio, + TQMX86_GPIIC_MASK(gpiic_irq), + TQMX86_GPIIC_CONFIG(gpiic_irq, type), + TQMX86_GPIIC); +} + +static void tqmx86_gpio_irq_mask(struct irq_data *data) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data( + irq_data_get_irq_chip_data(data)); + + scoped_guard(raw_spinlock_irqsave, &gpio->spinlock) { + gpio->irq_type[data->hwirq] &= ~TQMX86_INT_UNMASKED; + tqmx86_gpio_irq_config(gpio, data->hwirq); + } + + gpiochip_disable_irq(&gpio->chip, irqd_to_hwirq(data)); +} + +static void tqmx86_gpio_irq_unmask(struct irq_data *data) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data( + irq_data_get_irq_chip_data(data)); + + gpiochip_enable_irq(&gpio->chip, irqd_to_hwirq(data)); + + guard(raw_spinlock_irqsave)(&gpio->spinlock); + + gpio->irq_type[data->hwirq] |= TQMX86_INT_UNMASKED; + tqmx86_gpio_irq_config(gpio, data->hwirq); +} + +static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type) +{ + struct tqmx86_gpio_data *gpio = gpiochip_get_data( + irq_data_get_irq_chip_data(data)); + unsigned int edge_type = type & IRQF_TRIGGER_MASK; + u8 new_type; + + switch (edge_type) { + case IRQ_TYPE_EDGE_RISING: + new_type = TQMX86_INT_TRIG_RISING; + break; + case IRQ_TYPE_EDGE_FALLING: + new_type = TQMX86_INT_TRIG_FALLING; + break; + case IRQ_TYPE_EDGE_BOTH: + new_type = TQMX86_INT_TRIG_BOTH; + break; + default: + return -EINVAL; /* not supported */ + } + + guard(raw_spinlock_irqsave)(&gpio->spinlock); + + gpio->irq_type[data->hwirq] &= ~TQMX86_INT_TRIG_MASK; + gpio->irq_type[data->hwirq] |= new_type; + tqmx86_gpio_irq_config(gpio, data->hwirq); + + return 0; +} + +static void tqmx86_gpio_irq_handler(struct irq_desc *desc) +{ + struct gpio_chip *chip = irq_desc_get_handler_data(desc); + struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip); + struct irq_chip *irq_chip = irq_desc_get_chip(desc); + unsigned long irq_bits; + int i, hwirq; + u8 irq_status; + + chained_irq_enter(irq_chip, desc); + + irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS); + tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS); + + irq_bits = irq_status; + + scoped_guard(raw_spinlock_irqsave, &gpio->spinlock) { + for_each_set_bit(i, &irq_bits, TQMX86_NGPI) { + hwirq = i + TQMX86_NGPO; + + /* + * Edge-both triggers are implemented by flipping the + * edge trigger after each interrupt, as the controller + * only supports either rising or falling edge triggers, + * but not both. + * + * Internally, the TQMx86 GPIO controller has separate + * status registers for rising and falling edge + * interrupts. GPIIC configures which bits from which + * register are visible in the interrupt status register + * GPIIS and defines what triggers the parent IRQ line. + * Writing to GPIIS always clears both rising and + * falling interrupt flags internally, regardless of the + * currently configured trigger. + * + * In consequence, we can cleanly implement the + * edge-both trigger in software by first clearing the + * interrupt and then setting the new trigger based on + * the current GPIO input in tqmx86_gpio_irq_config() - + * even if an edge arrives between reading the input and + * setting the trigger, we will have a new interrupt + * pending. + */ + if ((gpio->irq_type[hwirq] & TQMX86_INT_TRIG_MASK) == + TQMX86_INT_TRIG_BOTH) + tqmx86_gpio_irq_config(gpio, hwirq); + } + } + + for_each_set_bit(i, &irq_bits, TQMX86_NGPI) + generic_handle_domain_irq(gpio->chip.irq.domain, + i + TQMX86_NGPO); + + chained_irq_exit(irq_chip, desc); +} + +/* Minimal runtime PM is needed by the IRQ subsystem */ +static int tqmx86_gpio_runtime_suspend(struct device *dev) +{ + return 0; +} + +static int tqmx86_gpio_runtime_resume(struct device *dev) +{ + return 0; +} + +static const struct dev_pm_ops tqmx86_gpio_dev_pm_ops = { + RUNTIME_PM_OPS(tqmx86_gpio_runtime_suspend, tqmx86_gpio_runtime_resume, NULL) +}; + +static void tqmx86_init_irq_valid_mask(struct gpio_chip *chip, + unsigned long *valid_mask, + unsigned int ngpios) +{ + /* Only GPIOs 4-7 are valid for interrupts. Clear the others */ + clear_bit(0, valid_mask); + clear_bit(1, valid_mask); + clear_bit(2, valid_mask); + clear_bit(3, valid_mask); +} + +static void tqmx86_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + + seq_puts(p, gc->label); +} + +static const struct irq_chip tqmx86_gpio_irq_chip = { + .irq_mask = tqmx86_gpio_irq_mask, + .irq_unmask = tqmx86_gpio_irq_unmask, + .irq_set_type = tqmx86_gpio_irq_set_type, + .irq_print_chip = tqmx86_gpio_irq_print_chip, + .flags = IRQCHIP_IMMUTABLE, + GPIOCHIP_IRQ_RESOURCE_HELPERS, +}; + +static int tqmx86_gpio_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct tqmx86_gpio_data *gpio; + struct gpio_chip *chip; + struct gpio_irq_chip *girq; + void __iomem *io_base; + struct resource *res; + int ret, irq; + + irq = platform_get_irq_optional(pdev, 0); + if (irq < 0 && irq != -ENXIO) + return irq; + + res = platform_get_resource(pdev, IORESOURCE_IO, 0); + if (!res) { + dev_err(&pdev->dev, "Cannot get I/O\n"); + return -ENODEV; + } + + io_base = devm_ioport_map(&pdev->dev, res->start, resource_size(res)); + if (!io_base) + return -ENOMEM; + + gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL); + if (!gpio) + return -ENOMEM; + + raw_spin_lock_init(&gpio->spinlock); + gpio->io_base = io_base; + + tqmx86_gpio_write(gpio, (u8)~TQMX86_DIR_INPUT_MASK, TQMX86_GPIODD); + + /* + * Reading the previous output state is not possible with TQMx86 hardware. + * Initialize all outputs to 0 to have a defined state that matches the + * shadow register. + */ + tqmx86_gpio_write(gpio, 0, TQMX86_GPIOD); + + chip = &gpio->chip; + chip->label = "gpio-tqmx86"; + chip->owner = THIS_MODULE; + chip->can_sleep = false; + chip->base = -1; + chip->direction_input = tqmx86_gpio_direction_input; + chip->direction_output = tqmx86_gpio_direction_output; + chip->get_direction = tqmx86_gpio_get_direction; + chip->get = tqmx86_gpio_get; + chip->set = tqmx86_gpio_set; + chip->ngpio = TQMX86_NGPIO; + chip->parent = pdev->dev.parent; + + pm_runtime_enable(&pdev->dev); + + if (irq > 0) { + u8 irq_status; + + /* Mask all interrupts */ + tqmx86_gpio_write(gpio, 0, TQMX86_GPIIC); + + /* Clear all pending interrupts */ + irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS); + tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS); + + girq = &chip->irq; + gpio_irq_chip_set_chip(girq, &tqmx86_gpio_irq_chip); + girq->parent_handler = tqmx86_gpio_irq_handler; + girq->num_parents = 1; + girq->parents = devm_kcalloc(&pdev->dev, 1, + sizeof(*girq->parents), + GFP_KERNEL); + if (!girq->parents) { + ret = -ENOMEM; + goto out_pm_dis; + } + girq->parents[0] = irq; + girq->default_type = IRQ_TYPE_NONE; + girq->handler = handle_simple_irq; + girq->init_valid_mask = tqmx86_init_irq_valid_mask; + + irq_domain_set_pm_device(girq->domain, dev); + } + + ret = devm_gpiochip_add_data(dev, chip, gpio); + if (ret) { + dev_err(dev, "Could not register GPIO chip\n"); + goto out_pm_dis; + } + + dev_info(dev, "GPIO functionality initialized with %d pins\n", + chip->ngpio); + + return 0; + +out_pm_dis: + pm_runtime_disable(&pdev->dev); + + return ret; +} + +static struct platform_driver tqmx86_gpio_driver = { + .driver = { + .name = "tqmx86-gpio", + .pm = pm_ptr(&tqmx86_gpio_dev_pm_ops), + }, + .probe = tqmx86_gpio_probe, +}; + +module_platform_driver(tqmx86_gpio_driver); + +MODULE_DESCRIPTION("TQMx86 PLD GPIO Driver"); +MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:tqmx86-gpio"); |