Add SGPIO driver support for Aspeed AST2500 SoC.

Signed-off-by: Hongwei Zhang <hongw...@ami.com>
---
 drivers/gpio/sgpio-aspeed.c | 487 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 487 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..ade2cb7
--- /dev/null
+++ b/drivers/gpio/sgpio-aspeed.c
@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2019 American Megatrends International LLC.
+ *
+ * Author: Karthikeyan Mani <karthikey...@amiindia.co.in>
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/gpio/aspeed.h>
+#include <linux/hashtable.h>
+#include <linux/bitfield.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/gpio.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)
+
+// default sgpio direction is input.
+static uint32_t sgpio_dir_val[3] = {0xffffffff, 0xffffffff, 0xffffffff };
+
+struct aspeed_sgpio {
+       struct gpio_chip chip;
+       struct clk *pclk;
+       spinlock_t lock;
+       void __iomem *base;
+       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 sampled on the
+ *       line even when the GPIO is configured as an output. Since
+ *       that input goes through synchronizers, writing, then reading
+ *       back may not return the written value right away.
+ *
+ *       The "rdata" register returns the content of the write latch
+ *       and thus can be used to read back what was last written
+ *       reliably.
+ */
+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_VAL_DIR        0x04
+#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
+
+/* This will be resolved at compile time */
+static inline 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);
+
+       if (sgpio_dir_val[GPIO_BANK(offset)] & GPIO_BIT(offset))
+               return !!(ioread32(bank_reg(gpio, bank, reg_val)) & 
GPIO_BIT(offset));
+       else
+               return !!(ioread32(bank_reg(gpio, bank, reg_rdata)) & 
GPIO_BIT(offset));
+
+}
+
+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);
+
+       iowrite32(reg, addr);
+       spin_unlock_irqrestore(&gpio->lock, flags);
+}
+
+static int aspeed_sgpio_dir_in(struct gpio_chip *gc, unsigned int offset)
+{
+       sgpio_dir_val[GPIO_BANK(offset)] |= GPIO_BIT(offset);
+       return 0;
+}
+
+static int aspeed_sgpio_dir_out(struct gpio_chip *gc, unsigned int offset, int 
val)
+{
+       sgpio_dir_val[GPIO_BANK(offset)] &= ~GPIO_BIT(offset);
+       return 0;
+}
+
+static int aspeed_sgpio_get_direction(struct gpio_chip *gc, unsigned int 
offset)
+{
+       return sgpio_dir_val[GPIO_BANK(offset)] & GPIO_BIT(offset);
+
+}
+
+static inline int 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);
+
+       *gpio = internal;
+       *bank = to_bank(*offset);
+       *bit = GPIO_BIT(*offset);
+
+       return 0;
+}
+
+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 rc, offset;
+       u32 bit;
+
+       rc = irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
+       if (rc)
+               return;
+
+       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 rc, offset;
+
+       rc = irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
+       if (rc)
+               return;
+
+       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 rc, offset;
+
+       rc = irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
+       if (rc)
+               return -EINVAL;
+
+       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, &reg, 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;
+       struct resource *res;
+       u32 nr_gpios, sgpio_freq;
+       int rc;
+       u16 sgpio_clk_div;
+       unsigned long apb_freq;
+
+       gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+       if (!gpio)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       gpio->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(gpio->base))
+               return PTR_ERR(gpio->base);
+
+       rc = of_property_read_u32(pdev->dev.of_node, "nr-gpios", &nr_gpios);
+       if ((rc < 0) || (nr_gpios > MAX_NR_SGPIO))
+               nr_gpios = MAX_NR_SGPIO;
+
+       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");
+               sgpio_freq = 12000000;
+       }
+
+       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);
+       sgpio_clk_div = 2 * ((apb_freq % sgpio_freq == 0) ?
+                            (apb_freq / sgpio_freq) - 1 : (apb_freq / 
sgpio_freq));
+       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 =  ARCH_NR_GPIOS - MAX_NR_SGPIO;
+
+       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

>

thanks Anrew, please review v3 at above and also inline comments at below.

>
> From: Andrew Jeffery <and...@aj.id.au>
> Sent: Wednesday, July 10, 2019 9:46 PM
> To:   Hongwei Zhang; Bartosz Golaszewski; Joel Stanley; Linus Walleij
> Cc:   linux-g...@vger.kernel.org; linux-arm-ker...@lists.infradead.org; 
> linux-asp...@lists.ozlabs.org; 
> linux-kernel@vger.kernel.org
> Subject:      Re: [PATCH 2/3 v2] ARM: dts: aspeed: Add SGPIO driver
> 
> 
> 
> On Thu, 11 Jul 2019, at 00:56, Hongwei Zhang wrote:
> > Add SGPIO driver support for Aspeed AST2500 SoC.
> > 
> > Signed-off-by: Hongwei Zhang <hongw...@ami.com>
> > ---
> >  drivers/gpio/sgpio-aspeed.c | 450 
> > ++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 450 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..0743d22
> > --- /dev/null
> > +++ b/drivers/gpio/sgpio-aspeed.c
> > @@ -0,0 +1,450 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright 2019 American Megatrends International LLC.
> > + *
> > + * Author: Karthikeyan Mani <karthikey...@amiindia.co.in>  */
> > +
> > +#include <linux/gpio/driver.h>
> > +#include <linux/gpio/aspeed.h>
> > +#include <linux/hashtable.h>
> > +#include <linux/init.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/pinctrl/consumer.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/string.h>
> > +
> > +#define NR_SGPIO        80
> > +
> > +struct aspeed_sgpio {
> > +   struct gpio_chip chip;
> > +   spinlock_t lock;
> > +   void __iomem *base;
> > +   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 sampled on the
> > + *       line even when the GPIO is configured as an output. Since
> > + *       that input goes through synchronizers, writing, then reading
> > + *       back may not return the written value right away.
> > + *
> > + *       The "rdata" register returns the content of the write latch
> > + *       and thus can be used to read back what was last written
> > + *       reliably.
> > + */
> > +
> > +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_VAL_DIR        0x04
> > +#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
> > +
> > +/* This will be resolved at compile time */ static inline 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 */
> > +           WARN_ON(reg);
> > +           return gpio->base;
> > +   }
> > +}
> > +

updated to use BUG_ON(1), please see v3.

> > +#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);
> > +
> > +   return !!(ioread32(bank_reg(gpio, bank, reg_val)) & 
> > +GPIO_BIT(offset)); }
> > +
> > +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);
> > +
> > +   iowrite32(reg, addr);
> > +   spin_unlock_irqrestore(&gpio->lock, flags); }
> > +
> > +static int aspeed_sgpio_dir_in(struct gpio_chip *gc, unsigned int
> > offset)
> > +{
> > +   /* By default all SGPIO Pins are input */
> > +   return 0;
> > +}
> > +
> > +static int aspeed_sgpio_dir_out(struct gpio_chip *gc, unsigned int
> > offset, int val)
> > +{
> > +   return 0;
> > +}
> > +
> > +static int aspeed_sgpio_get_direction(struct gpio_chip *gc, unsigned
> > int offset)
> > +{
> > +   /* By default all SGPIO Pins are input */
> > +   return 1;
> > +
> > +}
> 
> Please see my follow-up reply on v1 that helps clarify what we should do with 
> the 
> dir_in()/dir_out()/get_direction() implementations. The implementation here 
> will confuse everything in 
> the stack above it.
> 

updated, please see v3.

> > +
> > +static inline int 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);
> > +
> > +   *gpio = internal;
> > +   *bank = to_bank(*offset);
> > +   *bit = GPIO_BIT(*offset);
> > +
> > +   return 0;
> > +}
> > +
> > +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 rc, offset;
> > +   u32 bit;
> > +
> > +   rc = irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
> > +   if (rc)
> > +           return;
> > +
> > +   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 rc, offset;
> > +
> > +   rc = irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
> > +   if (rc)
> > +           return;
> > +
> > +   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 rc, offset;
> > +
> > +   rc = irqd_to_aspeed_sgpio_data(d, &gpio, &bank, &bit, &offset);
> > +   if (rc)
> > +           return -EINVAL;
> > +
> > +   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, &reg, 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 int aspeed_sgpio_request(struct gpio_chip *chip, unsigned int
> > offset)
> > +{
> > +   return (offset < NR_SGPIO);
> > +}
> 
> I don't think this request() implementation is helpful, especially as it 
> stands in the face of needing to pull 
> the number of GPIOs to serialise from the devicetree.
> 
> request() is an optional callback, lets just drop it.
> 

updated, please see v3.

> > +
> > +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;
> > +   struct resource *res;
> > +   int rc;
> > +
> > +   gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
> > +   if (!gpio)
> > +           return -ENOMEM;
> > +
> > +   res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +   gpio->base = devm_ioremap_resource(&pdev->dev, res);
> > +   if (IS_ERR(gpio->base))
> > +           return PTR_ERR(gpio->base);
> > +
> > +   spin_lock_init(&gpio->lock);
> > +
> > +   gpio->chip.parent = &pdev->dev;
> > +   gpio->chip.ngpio = NR_SGPIO;
> > +   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 = aspeed_sgpio_request;
> > +   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;
> > +
> > +   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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