GPIO: gpio-dwapb: Enable platform driver binding to MFD driver

The Synopsys DesignWare APB GPIO driver only supports open firmware devices.
But, like Intel Quark X1000 SOC, which has a single PCI function exporting
a GPIO and an I2C controller, it is a Multifunction device. This patch is
to enable the current Synopsys DesignWare APB GPIO driver to support the
Multifunction device which exports the designware GPIO controller.

Reviewed-by: Hock Leong Kweh <hock.leong.kweh@intel.com>
Signed-off-by: Weike Chen <alvin.chen@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

2 files changed, 167 insertions, 58 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ec398bee7c60..d9ffb6dfa54b 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -136,7 +136,6 @@ config GPIO_DWAPB
         tristate "Synopsys DesignWare APB GPIO driver"
         select GPIO_GENERIC
         select GENERIC_IRQ_CHIP
-        depends on OF_GPIO
         help
           Say Y or M here to build support for the Synopsys DesignWare APB
           GPIO block.
diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index d6618a6e2399..27466b5af5e8 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -21,6 +21,8 @@
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
+#include <linux/platform_data/gpio-dwapb.h>
+#include <linux/slab.h>
 
 #define GPIO_SWPORTA_DR         0x00
 #define GPIO_SWPORTA_DDR        0x04
@@ -84,11 +86,10 @@ static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
         writel(v, gpio->regs + GPIO_INT_POLARITY);
 }
 
-static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
+static u32 dwapb_do_irq(struct dwapb_gpio *gpio)
 {
-        struct dwapb_gpio *gpio = irq_get_handler_data(irq);
-        struct irq_chip *chip = irq_desc_get_chip(desc);
         u32 irq_status = readl_relaxed(gpio->regs + GPIO_INTSTATUS);
+        u32 ret = irq_status;
 
         while (irq_status) {
                 int hwirq = fls(irq_status) - 1;
@@ -102,6 +103,16 @@ static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
                         dwapb_toggle_trigger(gpio, hwirq);
         }
 
+        return ret;
+}
+
+static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
+{
+        struct dwapb_gpio *gpio = irq_get_handler_data(irq);
+        struct irq_chip *chip = irq_desc_get_chip(desc);
+
+        dwapb_do_irq(gpio);
+
         if (chip->irq_eoi)
                 chip->irq_eoi(irq_desc_get_irq_data(desc));
 }
@@ -207,22 +218,26 @@ static int dwapb_irq_set_type(struct irq_data *d, u32 type)
         return 0;
 }
 
+static irqreturn_t dwapb_irq_handler_mfd(int irq, void *dev_id)
+{
+        u32 worked;
+        struct dwapb_gpio *gpio = dev_id;
+
+        worked = dwapb_do_irq(gpio);
+
+        return worked ? IRQ_HANDLED : IRQ_NONE;
+}
+
 static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
-                                 struct dwapb_gpio_port *port)
+                                 struct dwapb_gpio_port *port,
+                                 struct dwapb_port_property *pp)
 {
         struct gpio_chip *gc = &port->bgc.gc;
-        struct device_node *node =  gc->of_node;
-        struct irq_chip_generic *irq_gc;
+        struct device_node *node = pp->node;
+        struct irq_chip_generic *irq_gc = NULL;
         unsigned int hwirq, ngpio = gc->ngpio;
         struct irq_chip_type *ct;
-        int err, irq, i;
-
-        irq = irq_of_parse_and_map(node, 0);
-        if (!irq) {
-                dev_warn(gpio->dev, "no irq for bank %s\n",
-                        port->bgc.gc.of_node->full_name);
-                return;
-        }
+        int err, i;
 
         gpio->domain = irq_domain_add_linear(node, ngpio,
                                              &irq_generic_chip_ops, gpio);
@@ -269,8 +284,24 @@ static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
         irq_gc->chip_types[1].type = IRQ_TYPE_EDGE_BOTH;
         irq_gc->chip_types[1].handler = handle_edge_irq;
 
-        irq_set_chained_handler(irq, dwapb_irq_handler);
-        irq_set_handler_data(irq, gpio);
+        if (!pp->irq_shared) {
+                irq_set_chained_handler(pp->irq, dwapb_irq_handler);
+                irq_set_handler_data(pp->irq, gpio);
+        } else {
+                /*
+                 * Request a shared IRQ since where MFD would have devices
+                 * using the same irq pin
+                 */
+                err = devm_request_irq(gpio->dev, pp->irq,
+                                       dwapb_irq_handler_mfd,
+                                       IRQF_SHARED, "gpio-dwapb-mfd", gpio);
+                if (err) {
+                        dev_err(gpio->dev, "error requesting IRQ\n");
+                        irq_domain_remove(gpio->domain);
+                        gpio->domain = NULL;
+                        return;
+                }
+        }
 
         for (hwirq = 0 ; hwirq < ngpio ; hwirq++)
                 irq_create_mapping(gpio->domain, hwirq);
@@ -296,57 +327,42 @@ static void dwapb_irq_teardown(struct dwapb_gpio *gpio)
 }
 
 static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
-                               struct device_node *port_np,
+                               struct dwapb_port_property *pp,
                                unsigned int offs)
 {
         struct dwapb_gpio_port *port;
-        u32 port_idx, ngpio;
         void __iomem *dat, *set, *dirout;
         int err;
 
-        if (of_property_read_u32(port_np, "reg", &port_idx) ||
-                port_idx >= DWAPB_MAX_PORTS) {
-                dev_err(gpio->dev, "missing/invalid port index for %s\n",
-                        port_np->full_name);
-                return -EINVAL;
-        }
-
         port = &gpio->ports[offs];
         port->gpio = gpio;
 
-        if (of_property_read_u32(port_np, "snps,nr-gpios", &ngpio)) {
-                dev_info(gpio->dev, "failed to get number of gpios for %s\n",
-                         port_np->full_name);
-                ngpio = 32;
-        }
-
-        dat = gpio->regs + GPIO_EXT_PORTA + (port_idx * GPIO_EXT_PORT_SIZE);
-        set = gpio->regs + GPIO_SWPORTA_DR + (port_idx * GPIO_SWPORT_DR_SIZE);
+        dat = gpio->regs + GPIO_EXT_PORTA + (pp->idx * GPIO_EXT_PORT_SIZE);
+        set = gpio->regs + GPIO_SWPORTA_DR + (pp->idx * GPIO_SWPORT_DR_SIZE);
         dirout = gpio->regs + GPIO_SWPORTA_DDR +
-                (port_idx * GPIO_SWPORT_DDR_SIZE);
+                (pp->idx * GPIO_SWPORT_DDR_SIZE);
 
         err = bgpio_init(&port->bgc, gpio->dev, 4, dat, set, NULL, dirout,
                          NULL, false);
         if (err) {
                 dev_err(gpio->dev, "failed to init gpio chip for %s\n",
-                        port_np->full_name);
+                        pp->name);
                 return err;
         }
 
-        port->bgc.gc.ngpio = ngpio;
-        port->bgc.gc.of_node = port_np;
+#ifdef CONFIG_OF_GPIO
+        port->bgc.gc.of_node = pp->node;
+#endif
+        port->bgc.gc.ngpio = pp->ngpio;
+        port->bgc.gc.base = pp->gpio_base;
 
-        /*
-         * Only port A can provide interrupts in all configurations of the IP.
-         */
-        if (port_idx == 0 &&
-            of_property_read_bool(port_np, "interrupt-controller"))
-                dwapb_configure_irqs(gpio, port);
+        if (pp->irq)
+                dwapb_configure_irqs(gpio, port, pp);
 
         err = gpiochip_add(&port->bgc.gc);
         if (err)
                 dev_err(gpio->dev, "failed to register gpiochip for %s\n",
-                        port_np->full_name);
+                        pp->name);
         else
                 port->is_registered = true;
 
@@ -362,25 +378,116 @@ static void dwapb_gpio_unregister(struct dwapb_gpio *gpio)
                         gpiochip_remove(&gpio->ports[m].bgc.gc);
 }
 
+static struct dwapb_platform_data *
+dwapb_gpio_get_pdata_of(struct device *dev)
+{
+        struct device_node *node, *port_np;
+        struct dwapb_platform_data *pdata;
+        struct dwapb_port_property *pp;
+        int nports;
+        int i;
+
+        node = dev->of_node;
+        if (!IS_ENABLED(CONFIG_OF_GPIO) || !node)
+                return ERR_PTR(-ENODEV);
+
+        nports = of_get_child_count(node);
+        if (nports == 0)
+                return ERR_PTR(-ENODEV);
+
+        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+        if (!pdata)
+                return ERR_PTR(-ENOMEM);
+
+        pdata->properties = kcalloc(nports, sizeof(*pp), GFP_KERNEL);
+        if (!pdata->properties) {
+                kfree(pdata);
+                return ERR_PTR(-ENOMEM);
+        }
+
+        pdata->nports = nports;
+
+        i = 0;
+        for_each_child_of_node(node, port_np) {
+                pp = &pdata->properties[i++];
+                pp->node = port_np;
+
+                if (of_property_read_u32(port_np, "reg", &pp->idx) ||
+                    pp->idx >= DWAPB_MAX_PORTS) {
+                        dev_err(dev, "missing/invalid port index for %s\n",
+                                port_np->full_name);
+                        kfree(pdata->properties);
+                        kfree(pdata);
+                        return ERR_PTR(-EINVAL);
+                }
+
+                if (of_property_read_u32(port_np, "snps,nr-gpios",
+                                         &pp->ngpio)) {
+                        dev_info(dev, "failed to get number of gpios for %s\n",
+                                 port_np->full_name);
+                        pp->ngpio = 32;
+                }
+
+                /*
+                 * Only port A can provide interrupts in all configurations of
+                 * the IP.
+                 */
+                if (pp->idx == 0 &&
+                    of_property_read_bool(port_np, "interrupt-controller")) {
+                        pp->irq = irq_of_parse_and_map(port_np, 0);
+                        if (!pp->irq) {
+                                dev_warn(dev, "no irq for bank %s\n",
+                                         port_np->full_name);
+                        }
+                }
+
+                pp->irq_shared  = false;
+                pp->gpio_base   = -1;
+                pp->name        = port_np->full_name;
+        }
+
+        return pdata;
+}
+
+static inline void dwapb_free_pdata_of(struct dwapb_platform_data *pdata)
+{
+        if (!IS_ENABLED(CONFIG_OF_GPIO) || !pdata)
+                return;
+
+        kfree(pdata->properties);
+        kfree(pdata);
+}
+
 static int dwapb_gpio_probe(struct platform_device *pdev)
 {
+        unsigned int i;
         struct resource *res;
         struct dwapb_gpio *gpio;
-        struct device_node *np;
         int err;
-        unsigned int offs = 0;
+        struct device *dev = &pdev->dev;
+        struct dwapb_platform_data *pdata = dev_get_platdata(dev);
+        bool is_pdata_alloc = !pdata;
+
+        if (is_pdata_alloc) {
+                pdata = dwapb_gpio_get_pdata_of(dev);
+                if (IS_ERR(pdata))
+                        return PTR_ERR(pdata);
+        }
 
-        gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
-        if (!gpio)
-                return -ENOMEM;
-        gpio->dev = &pdev->dev;
+        if (!pdata->nports) {
+                err = -ENODEV;
+                goto out_err;
+        }
 
-        gpio->nr_ports = of_get_child_count(pdev->dev.of_node);
-        if (!gpio->nr_ports) {
-                err = -EINVAL;
+        gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+        if (!gpio) {
+                err = -ENOMEM;
                 goto out_err;
         }
-        gpio->ports = devm_kzalloc(&pdev->dev, gpio->nr_ports *
+        gpio->dev = &pdev->dev;
+        gpio->nr_ports = pdata->nports;
+
+        gpio->ports = devm_kcalloc(&pdev->dev, gpio->nr_ports,
                                    sizeof(*gpio->ports), GFP_KERNEL);
         if (!gpio->ports) {
                 err = -ENOMEM;
@@ -394,20 +501,23 @@ static int dwapb_gpio_probe(struct platform_device *pdev)
                 goto out_err;
         }
 
-        for_each_child_of_node(pdev->dev.of_node, np) {
-                err = dwapb_gpio_add_port(gpio, np, offs++);
+        for (i = 0; i < gpio->nr_ports; i++) {
+                err = dwapb_gpio_add_port(gpio, &pdata->properties[i], i);
                 if (err)
                         goto out_unregister;
         }
         platform_set_drvdata(pdev, gpio);
 
-        return 0;
+        goto out_err;
 
 out_unregister:
         dwapb_gpio_unregister(gpio);
         dwapb_irq_teardown(gpio);
 
 out_err:
+        if (is_pdata_alloc)
+                dwapb_free_pdata_of(pdata);
+
         return err;
 }