[PATCH v2 1/2] gpio/aspeed-sgpio: enable access to all 80 input & output sgpios
Joel Stanley
joel at jms.id.au
Fri Sep 11 12:20:44 AEST 2020
On Fri, 11 Sep 2020 at 02:11, Jeremy Kerr <jk at codeconstruct.com.au> wrote:
>
> Currently, the aspeed-sgpio driver exposes up to 80 GPIO lines,
> corresponding to the 80 status bits available in hardware. Each of these
> lines can be configured as either an input or an output.
>
> However, each of these GPIOs is actually an input *and* an output; we
> actually have 80 inputs plus 80 outputs.
>
> This change expands the maximum number of GPIOs to 160; the lower half
> of this range are the input-only GPIOs, the upper half are the outputs.
> We fix the GPIO directions to correspond to this mapping.
>
> This also fixes a bug when setting GPIOs - we were reading from the
> input register, making it impossible to set more than one output GPIO.
>
> Signed-off-by: Jeremy Kerr <jk at codeconstruct.com.au>
> Fixes: 7db47faae79b ("gpio: aspeed: Add SGPIO driver")
Reviewed-by: Joel Stanley <joel at jms.id.au>
>
> ---
> v2:
> - Fix warnings from kbuild test robot
> - Add comment for input/output GPIO numbering
> ---
> .../devicetree/bindings/gpio/sgpio-aspeed.txt | 5 +-
> drivers/gpio/gpio-aspeed-sgpio.c | 126 ++++++++++++------
> 2 files changed, 87 insertions(+), 44 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt b/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
> index d4d83916c09d..be329ea4794f 100644
> --- a/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
> +++ b/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
> @@ -20,8 +20,9 @@ Required properties:
> - gpio-controller : Marks the device node as a GPIO controller
> - interrupts : Interrupt specifier, see interrupt-controller/interrupts.txt
> - interrupt-controller : Mark the GPIO controller as an interrupt-controller
> -- ngpios : number of GPIO lines, see gpio.txt
> - (should be multiple of 8, up to 80 pins)
> +- ngpios : number of *hardware* GPIO lines, see gpio.txt. This will expose
> + 2 software GPIOs per hardware GPIO: one for hardware input, one for hardware
> + output. Up to 80 pins, must be a multiple of 8.
> - clocks : A phandle to the APB clock for SGPM clock division
> - bus-frequency : SGPM CLK frequency
>
> diff --git a/drivers/gpio/gpio-aspeed-sgpio.c b/drivers/gpio/gpio-aspeed-sgpio.c
> index 3aa45934d60c..a18ca52432e0 100644
> --- a/drivers/gpio/gpio-aspeed-sgpio.c
> +++ b/drivers/gpio/gpio-aspeed-sgpio.c
> @@ -17,7 +17,17 @@
> #include <linux/spinlock.h>
> #include <linux/string.h>
>
> -#define MAX_NR_SGPIO 80
> +/*
> + * MAX_NR_HW_GPIO represents the number of actual hardware-supported GPIOs (ie,
> + * slots within the clocked serial GPIO data). Since each HW GPIO is both an
> + * input and an output, we provide MAX_NR_HW_GPIO * 2 lines on our gpiochip
> + * device.
> + *
> + * We use SGPIO_OUTPUT_OFFSET to define the split between the inputs and
> + * outputs; the inputs start at line 0, the outputs start at OUTPUT_OFFSET.
> + */
> +#define MAX_NR_HW_SGPIO 80
> +#define SGPIO_OUTPUT_OFFSET MAX_NR_HW_SGPIO
>
> #define ASPEED_SGPIO_CTRL 0x54
>
> @@ -30,8 +40,8 @@ struct aspeed_sgpio {
> struct clk *pclk;
> spinlock_t lock;
> void __iomem *base;
> - uint32_t dir_in[3];
> int irq;
> + int n_sgpio;
> };
>
> struct aspeed_sgpio_bank {
> @@ -111,31 +121,69 @@ static void __iomem *bank_reg(struct aspeed_sgpio *gpio,
> }
> }
>
> -#define GPIO_BANK(x) ((x) >> 5)
> -#define GPIO_OFFSET(x) ((x) & 0x1f)
> +#define GPIO_BANK(x) ((x % SGPIO_OUTPUT_OFFSET) >> 5)
> +#define GPIO_OFFSET(x) ((x % SGPIO_OUTPUT_OFFSET) & 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);
> + unsigned int bank;
> +
> + bank = GPIO_BANK(offset);
>
> WARN_ON(bank >= ARRAY_SIZE(aspeed_sgpio_banks));
> return &aspeed_sgpio_banks[bank];
> }
>
> +static int aspeed_sgpio_init_valid_mask(struct gpio_chip *gc,
> + unsigned long *valid_mask, unsigned int ngpios)
> +{
> + struct aspeed_sgpio *sgpio = gpiochip_get_data(gc);
> + int n = sgpio->n_sgpio;
> + int c = SGPIO_OUTPUT_OFFSET - n;
> +
> + WARN_ON(ngpios < MAX_NR_HW_SGPIO * 2);
> +
> + /* input GPIOs in the lower range */
> + bitmap_set(valid_mask, 0, n);
> + bitmap_clear(valid_mask, n, c);
> +
> + /* output GPIOS above SGPIO_OUTPUT_OFFSET */
> + bitmap_set(valid_mask, SGPIO_OUTPUT_OFFSET, n);
> + bitmap_clear(valid_mask, SGPIO_OUTPUT_OFFSET + n, c);
> +
> + return 0;
> +}
> +
> +static void aspeed_sgpio_irq_init_valid_mask(struct gpio_chip *gc,
> + unsigned long *valid_mask, unsigned int ngpios)
> +{
> + struct aspeed_sgpio *sgpio = gpiochip_get_data(gc);
> + int n = sgpio->n_sgpio;
> +
> + WARN_ON(ngpios < MAX_NR_HW_SGPIO * 2);
> +
> + /* input GPIOs in the lower range */
> + bitmap_set(valid_mask, 0, n);
> + bitmap_clear(valid_mask, n, ngpios - n);
> +}
> +
> +static bool aspeed_sgpio_is_input(unsigned int offset)
> +{
> + return offset < SGPIO_OUTPUT_OFFSET;
> +}
> +
> 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;
> + reg = aspeed_sgpio_is_input(offset) ? reg_val : reg_rdata;
> rc = !!(ioread32(bank_reg(gpio, bank, reg)) & GPIO_BIT(offset));
>
> spin_unlock_irqrestore(&gpio->lock, flags);
> @@ -143,22 +191,31 @@ static int aspeed_sgpio_get(struct gpio_chip *gc, unsigned int offset)
> return rc;
> }
>
> -static void sgpio_set_value(struct gpio_chip *gc, unsigned int offset, int val)
> +static int sgpio_set_value(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);
> - void __iomem *addr;
> + void __iomem *addr_r, *addr_w;
> u32 reg = 0;
>
> - addr = bank_reg(gpio, bank, reg_val);
> - reg = ioread32(addr);
> + if (aspeed_sgpio_is_input(offset))
> + return -EINVAL;
> +
> + /* Since this is an output, read the cached value from rdata, then
> + * update val. */
> + addr_r = bank_reg(gpio, bank, reg_rdata);
> + addr_w = bank_reg(gpio, bank, reg_val);
> +
> + reg = ioread32(addr_r);
>
> if (val)
> reg |= GPIO_BIT(offset);
> else
> reg &= ~GPIO_BIT(offset);
>
> - iowrite32(reg, addr);
> + iowrite32(reg, addr_w);
> +
> + return 0;
> }
>
> static void aspeed_sgpio_set(struct gpio_chip *gc, unsigned int offset, int val)
> @@ -175,43 +232,28 @@ static void aspeed_sgpio_set(struct gpio_chip *gc, unsigned int offset, int val)
>
> 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;
> + return aspeed_sgpio_is_input(offset) ? 0 : -EINVAL;
> }
>
> 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;
> + int rc;
>
> - spin_lock_irqsave(&gpio->lock, flags);
> -
> - gpio->dir_in[GPIO_BANK(offset)] &= ~GPIO_BIT(offset);
> - sgpio_set_value(gc, offset, val);
> + /* No special action is required for setting the direction; we'll
> + * error-out in sgpio_set_value if this isn't an output GPIO */
>
> + spin_lock_irqsave(&gpio->lock, flags);
> + rc = sgpio_set_value(gc, offset, val);
> spin_unlock_irqrestore(&gpio->lock, flags);
>
> - return 0;
> + return rc;
> }
>
> 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;
> -
> + return !!aspeed_sgpio_is_input(offset);
> }
>
> static void irqd_to_aspeed_sgpio_data(struct irq_data *d,
> @@ -402,6 +444,7 @@ static int aspeed_sgpio_setup_irqs(struct aspeed_sgpio *gpio,
>
> irq = &gpio->chip.irq;
> irq->chip = &aspeed_sgpio_irqchip;
> + irq->init_valid_mask = aspeed_sgpio_irq_init_valid_mask;
> irq->handler = handle_bad_irq;
> irq->default_type = IRQ_TYPE_NONE;
> irq->parent_handler = aspeed_sgpio_irq_handler;
> @@ -452,11 +495,12 @@ static int __init aspeed_sgpio_probe(struct platform_device *pdev)
> if (rc < 0) {
> dev_err(&pdev->dev, "Could not read ngpios property\n");
> return -EINVAL;
> - } else if (nr_gpios > MAX_NR_SGPIO) {
> + } else if (nr_gpios > MAX_NR_HW_SGPIO) {
> dev_err(&pdev->dev, "Number of GPIOs exceeds the maximum of %d: %d\n",
> - MAX_NR_SGPIO, nr_gpios);
> + MAX_NR_HW_SGPIO, nr_gpios);
> return -EINVAL;
> }
> + gpio->n_sgpio = nr_gpios;
>
> rc = of_property_read_u32(pdev->dev.of_node, "bus-frequency", &sgpio_freq);
> if (rc < 0) {
> @@ -497,7 +541,8 @@ static int __init aspeed_sgpio_probe(struct platform_device *pdev)
> spin_lock_init(&gpio->lock);
>
> gpio->chip.parent = &pdev->dev;
> - gpio->chip.ngpio = nr_gpios;
> + gpio->chip.ngpio = MAX_NR_HW_SGPIO * 2;
> + gpio->chip.init_valid_mask = aspeed_sgpio_init_valid_mask;
> gpio->chip.direction_input = aspeed_sgpio_dir_in;
> gpio->chip.direction_output = aspeed_sgpio_dir_out;
> gpio->chip.get_direction = aspeed_sgpio_get_direction;
> @@ -509,9 +554,6 @@ static int __init aspeed_sgpio_probe(struct platform_device *pdev)
> 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));
> -
> aspeed_sgpio_setup_irqs(gpio, pdev);
>
> rc = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
> --
> 2.28.0
>
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