This patch enumerates parallel modules in expansion slots and exposes
model numbers via sysfs.

Signed-off-by: Sergei Ianovich <ynv...@gmail.com>
---
   v3..v4
   * move DTS binding to a different patch (8/21)

   v2..v3
   * no changes (except number 13/16 -> 18/21)

   v0..v2
   * use device tree
   * use devm helpers where possible

 .../devicetree/bindings/misc/lp8x4x-bus.txt        |   9 ++
 Documentation/misc-devices/lp8x4x_bus.txt          |   8 ++
 drivers/misc/lp8x4x_bus.c                          | 119 +++++++++++++++++++++
 3 files changed, 136 insertions(+)

diff --git a/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt 
b/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt
index 24a8c62..75ac3b2 100644
--- a/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt
+++ b/Documentation/devicetree/bindings/misc/lp8x4x-bus.txt
@@ -7,6 +7,7 @@ Required properties:
 
 - reg: physical base addresses and region lengths of
        * the rotary switch
+       * 8 plugable industrial IO slots
        * the 8bit DIP switch
        * the serial slot select register
        * the slot count register
@@ -18,6 +19,14 @@ Example:
        backplane {
                compatible = "icpdas,backplane-lp8x4x";
                reg = <0x0 0x2
+                      0x1000 0x10
+                      0x2000 0x10
+                      0x3000 0x10
+                      0x4000 0x10
+                      0x5000 0x10
+                      0x6000 0x10
+                      0x7000 0x10
+                      0x8000 0x10
                       0x9002 0x2
                       0x9004 0x2
                       0x9046 0x2>;
diff --git a/Documentation/misc-devices/lp8x4x_bus.txt 
b/Documentation/misc-devices/lp8x4x_bus.txt
index 7b86797..09380fd 100644
--- a/Documentation/misc-devices/lp8x4x_bus.txt
+++ b/Documentation/misc-devices/lp8x4x_bus.txt
@@ -28,6 +28,9 @@ into the device, they could be accessed using the 2nd PXA 
built-in UART port
 (/dev/ttyS1). However, it seems that addresses are not processed by
 the modules. So the parallel bus needs to select which slot is connected.
 
+Parallel modules allow much faster communication. There are accessed using
+IO memory through the FPGA. Their ports are exposed via sysfs.
+
 SYSFS
 -----
 
@@ -50,3 +53,8 @@ rotary
 
 slot_count
        RO - shows total number of expansion slots on the device
+
+/sys/bus/icpdas/devices/slot%02i:
+
+model
+       RO - shows expansion module model number
diff --git a/drivers/misc/lp8x4x_bus.c b/drivers/misc/lp8x4x_bus.c
index e805640..59dc767 100644
--- a/drivers/misc/lp8x4x_bus.c
+++ b/drivers/misc/lp8x4x_bus.c
@@ -23,6 +23,13 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sergei Ianovich <ynv...@gmail.com>");
 MODULE_DESCRIPTION("ICP DAS LP-8x4x parallel bus driver");
 
+struct lp8x4x_slot {
+       void                    *data_addr;
+       unsigned int            model;
+       struct device           dev;
+};
+
+#define LP8X4X_MAX_SLOT_COUNT  8
 struct lp8x4x_master {
        unsigned int            slot_count;
        void                    *count_addr;
@@ -31,9 +38,45 @@ struct lp8x4x_master {
        struct gpio_desc        *eeprom_nWE;
        unsigned int            active_slot;
        void                    *switch_addr;
+       struct lp8x4x_slot      slot[LP8X4X_MAX_SLOT_COUNT];
        struct device           dev;
 };
 
+static unsigned char lp8x4x_model[256] = {
+          0,    0,    0, 0x11,    0, 0x18, 0x13, 0x11,
+       0x0e, 0x11,    0,    0,    0, 0x5a, 0x5b, 0x5c,
+       0x3c, 0x44, 0x34, 0x3a, 0x39, 0x36, 0x37, 0x33,
+       0x35, 0x40, 0x41, 0x42, 0x38, 0x3f, 0x32, 0x45,
+       0xac, 0x70, 0x8e, 0x8e, 0x1e, 0x72, 0x90, 0x29,
+       0x4a, 0x22, 0xd3, 0xd2, 0x28, 0x25, 0x2a, 0x29,
+       0x48, 0x49, 0x5d, 0x1f, 0x20, 0x23, 0x24, 0x4d,
+       0x3d, 0x3e,    0,    0,    0,    0,    0,    0,
+          0, 0x78, 0x72, 0x2b, 0x5e, 0x5e, 0x36, 0xae,
+       0x30,    0,    0,    0,    0,    0,    0,    0,
+          0,    0, 0x5c, 0x5e,    0, 0x5e,    0,    0,
+          0, 0x3b,    0,    0,    0,    0,    0,    0,
+          0, 0x50, 0x2e,    0, 0x58,    0,    0, 0x43,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0, 0x54,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0,
+          0,    0,    0,    0,    0,    0,    0,    0
+};
+
 static int lp8x4x_match(struct device *dev, struct device_driver *drv)
 {
        return 1;
@@ -44,6 +87,26 @@ static struct bus_type lp8x4x_bus_type = {
        .match          = lp8x4x_match,
 };
 
+static void lp8x4x_slot_release(struct device *dev)
+{
+}
+
+static ssize_t model_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct lp8x4x_slot *s = container_of(dev, struct lp8x4x_slot, dev);
+
+       return sprintf(buf, "%u\n", s->model + 8000);
+}
+
+static DEVICE_ATTR_RO(model);
+
+static struct attribute *slot_dev_attrs[] = {
+       &dev_attr_model.attr,
+       NULL,
+};
+ATTRIBUTE_GROUPS(slot_dev);
+
 static void lp8x4x_master_release(struct device *dev)
 {
        struct lp8x4x_master *m = container_of(dev, struct lp8x4x_master, dev);
@@ -173,18 +236,50 @@ ATTRIBUTE_GROUPS(master_dev);
 static void devm_lp8x4x_bus_release(struct device *dev, void *res)
 {
        struct lp8x4x_master *m = *(struct lp8x4x_master **)res;
+       struct lp8x4x_slot *s;
+       int i;
 
        dev_dbg(dev, "releasing devices\n");
+       for (i = 0; i < LP8X4X_MAX_SLOT_COUNT; i++) {
+               s = &m->slot[i];
+               if (s->model)
+                       device_unregister(&s->dev);
+       }
        device_unregister(&m->dev);
        bus_unregister(&lp8x4x_bus_type);
 }
 
+static void __init lp8x4x_bus_probe_slot(struct lp8x4x_master *m, int i,
+               unsigned char model)
+{
+       struct lp8x4x_slot *s = &m->slot[i];
+       int err;
+
+       dev_info(&m->dev, "found %u in slot %i\n", 8000 + model, i + 1);
+
+       s->dev.bus = &lp8x4x_bus_type;
+       dev_set_name(&s->dev, "slot%02i", i + 1);
+       s->dev.parent = &m->dev;
+       s->dev.release = lp8x4x_slot_release;
+       s->dev.groups = slot_dev_groups;
+       s->model = model;
+
+       err = device_register(&s->dev);
+       if (err < 0) {
+               dev_err(&s->dev, "failed to register device\n");
+               s->model = 0;
+               return;
+       }
+}
+
 static int __init lp8x4x_bus_probe(struct platform_device *pdev)
 {
        struct lp8x4x_master *m, **p;
        struct resource *res;
        int r = 0;
+       int i;
        int err = 0;
+       unsigned int model;
 
        m = kzalloc(sizeof(*m), GFP_KERNEL);
        if (!m)
@@ -211,6 +306,23 @@ static int __init lp8x4x_bus_probe(struct platform_device 
*pdev)
                goto err_free;
        }
 
+       for (i = 0; i < LP8X4X_MAX_SLOT_COUNT; i++) {
+               res = platform_get_resource(pdev, IORESOURCE_MEM, r++);
+               if (!res) {
+                       dev_err(&pdev->dev, "Failed to get slot %i address\n",
+                                       i);
+                       err = -ENODEV;
+                       goto err_free;
+               }
+
+               m->slot[i].data_addr = devm_ioremap_resource(&pdev->dev, res);
+               if (IS_ERR(m->slot[i].data_addr)) {
+                       dev_err(&pdev->dev, "Failed to ioremap slot %i\n", i);
+                       err = PTR_ERR(m->slot[i].data_addr);
+                       goto err_free;
+               }
+       }
+
        res = platform_get_resource(pdev, IORESOURCE_MEM, r++);
        if (!res) {
                dev_err(&pdev->dev, "Failed to get DIP switch address\n");
@@ -305,6 +417,13 @@ static int __init lp8x4x_bus_probe(struct platform_device 
*pdev)
        }
 
        devres_add(&pdev->dev, p);
+       for (i = 0; i < LP8X4X_MAX_SLOT_COUNT; i++) {
+               model = lp8x4x_model[ioread8(m->slot[i].data_addr)];
+               if (!model)
+                       continue;
+
+               lp8x4x_bus_probe_slot(m, i, model);
+       }
        return 0;
 
 err_bus:
-- 
1.8.4.2

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