[v6 2/2] gpio: aspeed: Add SGPIO driver
Andrew Jeffery
andrew at aj.id.au
Wed Jul 31 10:19:21 AEST 2019
On Wed, 31 Jul 2019, at 00:55, Hongwei Zhang wrote:
> Add SGPIO driver support for Aspeed AST2500 SoC.
>
> Signed-off-by: Hongwei Zhang <hongweiz at ami.com>
> ---
> drivers/gpio/sgpio-aspeed.c | 521 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 521 insertions(+)
> create mode 100644 drivers/gpio/sgpio-aspeed.c
>
> diff --git a/drivers/gpio/sgpio-aspeed.c b/drivers/gpio/sgpio-aspeed.c
> new file mode 100644
> index 0000000..9a17b1a
> --- /dev/null
> +++ b/drivers/gpio/sgpio-aspeed.c
> @@ -0,0 +1,521 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright 2019 American Megatrends International LLC.
> + *
> + * Author: Karthikeyan Mani <karthikeyanm at amiindia.co.in>
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/hashtable.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +#include <linux/string.h>
> +
> +#define MAX_NR_SGPIO 80
> +
> +#define ASPEED_SGPIO_CTRL 0x54
> +
> +#define ASPEED_SGPIO_PINS_MASK GENMASK(9, 6)
> +#define ASPEED_SGPIO_CLK_DIV_MASK GENMASK(31, 16)
> +#define ASPEED_SGPIO_ENABLE BIT(0)
> +
> +struct aspeed_sgpio {
> + struct gpio_chip chip;
> + struct clk *pclk;
> + spinlock_t lock;
> + void __iomem *base;
> + uint32_t dir_in[3];
> + int irq;
> +};
> +
> +struct aspeed_sgpio_bank {
> + uint16_t val_regs;
> + uint16_t rdata_reg;
> + uint16_t irq_regs;
> + const char names[4][3];
> +};
> +
> +/*
> + * Note: The "value" register returns the input value when the GPIO is
> + * configured as an input.
> + *
> + * The "rdata" register returns the output value when the GPIO is
> + * configured as an output.
> + */
> +static const struct aspeed_sgpio_bank aspeed_sgpio_banks[] = {
> + {
> + .val_regs = 0x0000,
> + .rdata_reg = 0x0070,
> + .irq_regs = 0x0004,
> + .names = { "A", "B", "C", "D" },
> + },
> + {
> + .val_regs = 0x001C,
> + .rdata_reg = 0x0074,
> + .irq_regs = 0x0020,
> + .names = { "E", "F", "G", "H" },
> + },
> + {
> + .val_regs = 0x0038,
> + .rdata_reg = 0x0078,
> + .irq_regs = 0x003C,
> + .names = { "I", "J" },
> + },
> +};
> +
> +enum aspeed_sgpio_reg {
> + reg_val,
> + reg_rdata,
> + reg_irq_enable,
> + reg_irq_type0,
> + reg_irq_type1,
> + reg_irq_type2,
> + reg_irq_status,
> +};
> +
> +#define GPIO_VAL_VALUE 0x00
> +#define GPIO_IRQ_ENABLE 0x00
> +#define GPIO_IRQ_TYPE0 0x04
> +#define GPIO_IRQ_TYPE1 0x08
> +#define GPIO_IRQ_TYPE2 0x0C
> +#define GPIO_IRQ_STATUS 0x10
> +
> +static void __iomem *bank_reg(struct aspeed_sgpio *gpio,
> + const struct aspeed_sgpio_bank *bank,
> + const enum aspeed_sgpio_reg reg)
> +{
> + 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_irq_enable:
> + return gpio->base + bank->irq_regs + GPIO_IRQ_ENABLE;
> + case reg_irq_type0:
> + return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE0;
> + case reg_irq_type1:
> + return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE1;
> + case reg_irq_type2:
> + return gpio->base + bank->irq_regs + GPIO_IRQ_TYPE2;
> + case reg_irq_status:
> + return gpio->base + bank->irq_regs + GPIO_IRQ_STATUS;
> + default:
> + /* acturally if code runs to here, it's an error case */
> + BUG_ON(1);
> + }
> +}
> +
> +#define GPIO_BANK(x) ((x) >> 5)
> +#define GPIO_OFFSET(x) ((x) & 0x1f)
> +#define GPIO_BIT(x) BIT(GPIO_OFFSET(x))
> +
> +static const struct aspeed_sgpio_bank *to_bank(unsigned int offset)
> +{
> + unsigned int bank = GPIO_BANK(offset);
> +
> + WARN_ON(bank >= ARRAY_SIZE(aspeed_sgpio_banks));
> + return &aspeed_sgpio_banks[bank];
> +}
> +
> +static int aspeed_sgpio_get(struct gpio_chip *gc, unsigned int offset)
> +{
> + struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> + const struct aspeed_sgpio_bank *bank = to_bank(offset);
> + unsigned long flags;
> + enum aspeed_sgpio_reg reg;
> + bool is_input;
> + int rc = 0;
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> +
> + is_input = gpio->dir_in[GPIO_BANK(offset)] & GPIO_BIT(offset);
> + reg = is_input ? reg_val : reg_rdata;
> + rc = !!(ioread32(bank_reg(gpio, bank, reg)) & GPIO_BIT(offset));
> +
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +
> + return rc;
> +}
> +
> +static void aspeed_sgpio_set(struct gpio_chip *gc, unsigned int
> offset, int val)
> +{
> + struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> + const struct aspeed_sgpio_bank *bank = to_bank(offset);
> + unsigned long flags;
> + void __iomem *addr;
> + u32 reg = 0;
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> +
> + addr = bank_reg(gpio, bank, reg_val);
> +
> + if (val)
> + reg |= GPIO_BIT(offset);
> + else
> + reg &= ~GPIO_BIT(offset);
reg is zero-initialised above and you haven't read from addr to assign to reg, so
the else branch is redundant (reg is already zeroed). This path has a bug - you're
clearing the state of all GPIOs associated with addr rather than just the GPIO
associated with offset.
> +
> + iowrite32(reg, addr);
> +
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +}
> +
> +static int aspeed_sgpio_dir_in(struct gpio_chip *gc, unsigned int
> offset)
> +{
> + struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> + gpio->dir_in[GPIO_BANK(offset)] |= GPIO_BIT(offset);
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +
> + return 0;
> +}
> +
> +static int aspeed_sgpio_dir_out(struct gpio_chip *gc, unsigned int
> offset, int val)
> +{
> + struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> + gpio->dir_in[GPIO_BANK(offset)] &= ~GPIO_BIT(offset);
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +
> + aspeed_sgpio_set(gc, offset, val);
In this case you should probably have an unlocked variant of aspeed_sgpio_set()
so you can call it inside the the critical section above instead of needing to
acquire/release the lock twice (once above and again in aspeed_sgpio_set()
as it stands).
Cheers,
Andrew
> +
> + return 0;
> +}
> +
> +static int aspeed_sgpio_get_direction(struct gpio_chip *gc, unsigned
> int offset)
> +{
> + int dir_status;
> + struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> + dir_status = gpio->dir_in[GPIO_BANK(offset)] & GPIO_BIT(offset);
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +
> + return dir_status;
> +
> +}
> +
> +static void irqd_to_aspeed_sgpio_data(struct irq_data *d,
> + struct aspeed_sgpio **gpio,
> + const struct aspeed_sgpio_bank **bank,
> + u32 *bit, int *offset)
> +{
> + struct aspeed_sgpio *internal;
> +
> + *offset = irqd_to_hwirq(d);
> + internal = irq_data_get_irq_chip_data(d);
> + WARN_ON(!internal);
> +
> + *gpio = internal;
> + *bank = to_bank(*offset);
> + *bit = GPIO_BIT(*offset);
> +}
> +
> +static void aspeed_sgpio_irq_ack(struct irq_data *d)
> +{
> + const struct aspeed_sgpio_bank *bank;
> + struct aspeed_sgpio *gpio;
> + unsigned long flags;
> + void __iomem *status_addr;
> + int offset;
> + u32 bit;
> +
> + irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
> +
> + status_addr = bank_reg(gpio, bank, reg_irq_status);
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> +
> + iowrite32(bit, status_addr);
> +
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +}
> +
> +static void aspeed_sgpio_irq_set_mask(struct irq_data *d, bool set)
> +{
> + const struct aspeed_sgpio_bank *bank;
> + struct aspeed_sgpio *gpio;
> + unsigned long flags;
> + u32 reg, bit;
> + void __iomem *addr;
> + int offset;
> +
> + irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
> + addr = bank_reg(gpio, bank, reg_irq_enable);
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> +
> + reg = ioread32(addr);
> + if (set)
> + reg |= bit;
> + else
> + reg &= ~bit;
> +
> + iowrite32(reg, addr);
> +
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +}
> +
> +static void aspeed_sgpio_irq_mask(struct irq_data *d)
> +{
> + aspeed_sgpio_irq_set_mask(d, false);
> +}
> +
> +static void aspeed_sgpio_irq_unmask(struct irq_data *d)
> +{
> + aspeed_sgpio_irq_set_mask(d, true);
> +}
> +
> +static int aspeed_sgpio_set_type(struct irq_data *d, unsigned int type)
> +{
> + u32 type0 = 0;
> + u32 type1 = 0;
> + u32 type2 = 0;
> + u32 bit, reg;
> + const struct aspeed_sgpio_bank *bank;
> + irq_flow_handler_t handler;
> + struct aspeed_sgpio *gpio;
> + unsigned long flags;
> + void __iomem *addr;
> + int offset;
> +
> + irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
> +
> + switch (type & IRQ_TYPE_SENSE_MASK) {
> + case IRQ_TYPE_EDGE_BOTH:
> + type2 |= bit;
> + /* fall through */
> + case IRQ_TYPE_EDGE_RISING:
> + type0 |= bit;
> + /* fall through */
> + case IRQ_TYPE_EDGE_FALLING:
> + handler = handle_edge_irq;
> + break;
> + case IRQ_TYPE_LEVEL_HIGH:
> + type0 |= bit;
> + /* fall through */
> + case IRQ_TYPE_LEVEL_LOW:
> + type1 |= bit;
> + handler = handle_level_irq;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + spin_lock_irqsave(&gpio->lock, flags);
> +
> + addr = bank_reg(gpio, bank, reg_irq_type0);
> + reg = ioread32(addr);
> + reg = (reg & ~bit) | type0;
> + iowrite32(reg, addr);
> +
> + addr = bank_reg(gpio, bank, reg_irq_type1);
> + reg = ioread32(addr);
> + reg = (reg & ~bit) | type1;
> + iowrite32(reg, addr);
> +
> + addr = bank_reg(gpio, bank, reg_irq_type2);
> + reg = ioread32(addr);
> + reg = (reg & ~bit) | type2;
> + iowrite32(reg, addr);
> +
> + spin_unlock_irqrestore(&gpio->lock, flags);
> +
> + irq_set_handler_locked(d, handler);
> +
> + return 0;
> +}
> +
> +static void aspeed_sgpio_irq_handler(struct irq_desc *desc)
> +{
> + struct gpio_chip *gc = irq_desc_get_handler_data(desc);
> + struct irq_chip *ic = irq_desc_get_chip(desc);
> + struct aspeed_sgpio *data = gpiochip_get_data(gc);
> + unsigned int i, p, girq;
> + unsigned long reg;
> +
> + chained_irq_enter(ic, desc);
> +
> + for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
> + const struct aspeed_sgpio_bank *bank = &aspeed_sgpio_banks[i];
> +
> + reg = ioread32(bank_reg(data, bank, reg_irq_status));
> +
> + for_each_set_bit(p, ®, 32) {
> + girq = irq_find_mapping(gc->irq.domain, i * 32 + p);
> + generic_handle_irq(girq);
> + }
> +
> + }
> +
> + chained_irq_exit(ic, desc);
> +}
> +
> +static struct irq_chip aspeed_sgpio_irqchip = {
> + .name = "aspeed-sgpio",
> + .irq_ack = aspeed_sgpio_irq_ack,
> + .irq_mask = aspeed_sgpio_irq_mask,
> + .irq_unmask = aspeed_sgpio_irq_unmask,
> + .irq_set_type = aspeed_sgpio_set_type,
> +};
> +
> +static int aspeed_sgpio_setup_irqs(struct aspeed_sgpio *gpio,
> + struct platform_device *pdev)
> +{
> + int rc, i;
> + const struct aspeed_sgpio_bank *bank;
> +
> + rc = platform_get_irq(pdev, 0);
> + if (rc < 0)
> + return rc;
> +
> + gpio->irq = rc;
> +
> + /* Disable IRQ and clear Interrupt status registers for all SPGIO
> Pins. */
> + for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
> + bank = &aspeed_sgpio_banks[i];
> + /* disable irq enable bits */
> + iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_enable));
> + /* clear status bits */
> + iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_status));
> + }
> +
> + rc = gpiochip_irqchip_add(&gpio->chip, &aspeed_sgpio_irqchip,
> + 0, handle_bad_irq, IRQ_TYPE_NONE);
> + if (rc) {
> + dev_info(&pdev->dev, "Could not add irqchip\n");
> + return rc;
> + }
> +
> + gpiochip_set_chained_irqchip(&gpio->chip, &aspeed_sgpio_irqchip,
> + gpio->irq, aspeed_sgpio_irq_handler);
> +
> + /* set IRQ settings and Enable Interrupt */
> + for (i = 0; i < ARRAY_SIZE(aspeed_sgpio_banks); i++) {
> + bank = &aspeed_sgpio_banks[i];
> + /* set falling or level-low irq */
> + iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_type0));
> + /* trigger type is edge */
> + iowrite32(0x00000000, bank_reg(gpio, bank, reg_irq_type1));
> + /* dual edge trigger mode. */
> + iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_type2));
> + /* enable irq */
> + iowrite32(0xffffffff, bank_reg(gpio, bank, reg_irq_enable));
> + }
> +
> + return 0;
> +}
> +
> +static const struct of_device_id aspeed_sgpio_of_table[] = {
> + { .compatible = "aspeed,ast2400-sgpio" },
> + { .compatible = "aspeed,ast2500-sgpio" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, aspeed_sgpio_of_table);
> +
> +static int __init aspeed_sgpio_probe(struct platform_device *pdev)
> +{
> + struct aspeed_sgpio *gpio;
> + u32 nr_gpios, sgpio_freq, sgpio_clk_div;
> + int rc;
> + unsigned long apb_freq;
> +
> + gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
> + if (!gpio)
> + return -ENOMEM;
> +
> + gpio->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(gpio->base))
> + return PTR_ERR(gpio->base);
> +
> + rc = of_property_read_u32(pdev->dev.of_node, "ngpios", &nr_gpios);
> + if (rc < 0) {
> + dev_err(&pdev->dev, "Could not read ngpios property\n");
> + return -EINVAL;
> + } else if (nr_gpios > MAX_NR_SGPIO) {
> + dev_err(&pdev->dev, "Number of GPIOs exceeds the maximum of %d:
> %d\n",
> + MAX_NR_SGPIO, nr_gpios);
> + return -EINVAL;
> + }
> +
> + rc = of_property_read_u32(pdev->dev.of_node, "bus-frequency",
> &sgpio_freq);
> + if (rc < 0) {
> + dev_err(&pdev->dev, "Could not read bus-frequency property\n");
> + return -EINVAL;
> + }
> +
> + gpio->pclk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(gpio->pclk)) {
> + dev_err(&pdev->dev, "devm_clk_get failed\n");
> + return PTR_ERR(gpio->pclk);
> + }
> +
> + apb_freq = clk_get_rate(gpio->pclk);
> +
> + /*
> + * From the datasheet,
> + * SGPIO period = 1/PCLK * 2 * (GPIO254[31:16] + 1)
> + * period = 2 * (GPIO254[31:16] + 1) / PCLK
> + * frequency = 1 / (2 * (GPIO254[31:16] + 1) / PCLK)
> + * frequency = PCLK / (2 * (GPIO254[31:16] + 1))
> + * frequency * 2 * (GPIO254[31:16] + 1) = PCLK
> + * GPIO254[31:16] = PCLK / (frequency * 2) - 1
> + */
> + if (sgpio_freq == 0)
> + return -EINVAL;
> +
> + sgpio_clk_div = (apb_freq / (sgpio_freq * 2)) - 1;
> +
> + if (sgpio_clk_div > (1 << 16) - 1)
> + return -EINVAL;
> +
> + iowrite32(FIELD_PREP(ASPEED_SGPIO_CLK_DIV_MASK, sgpio_clk_div) |
> + FIELD_PREP(ASPEED_SGPIO_PINS_MASK, (nr_gpios / 8)) |
> + ASPEED_SGPIO_ENABLE,
> + gpio->base + ASPEED_SGPIO_CTRL);
> +
> + spin_lock_init(&gpio->lock);
> +
> + gpio->chip.parent = &pdev->dev;
> + gpio->chip.ngpio = nr_gpios;
> + gpio->chip.direction_input = aspeed_sgpio_dir_in;
> + gpio->chip.direction_output = aspeed_sgpio_dir_out;
> + gpio->chip.get_direction = aspeed_sgpio_get_direction;
> + gpio->chip.request = NULL;
> + gpio->chip.free = NULL;
> + gpio->chip.get = aspeed_sgpio_get;
> + gpio->chip.set = aspeed_sgpio_set;
> + gpio->chip.set_config = NULL;
> + gpio->chip.label = dev_name(&pdev->dev);
> + gpio->chip.base = -1;
> +
> + /* set all SGPIO pins as input (1). */
> + memset(gpio->dir_in, 0xff, sizeof(gpio->dir_in));
> +
> + rc = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
> + if (rc < 0)
> + return rc;
> +
> + return aspeed_sgpio_setup_irqs(gpio, pdev);
> +}
> +
> +static struct platform_driver aspeed_sgpio_driver = {
> + .driver = {
> + .name = KBUILD_MODNAME,
> + .of_match_table = aspeed_sgpio_of_table,
> + },
> +};
> +
> +module_platform_driver_probe(aspeed_sgpio_driver, aspeed_sgpio_probe);
> +MODULE_DESCRIPTION("Aspeed Serial GPIO Driver");
> +MODULE_LICENSE("GPL");
> --
> 2.7.4
>
>
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