[PATCH 09/13] mfd: omap-usb-host: Add device tree support and binding information

Hi,

On Tuesday 05 February 2013 04:28 PM, Roger Quadros wrote:

On 02/05/2013 08:16 AM, kishon wrote:

quoted

On Monday 04 February 2013 09:28 PM, Roger Quadros wrote:

quoted

Allows the OMAP HS USB host controller to be specified
via device tree.

CC: Samuel Ortiz <redacted>
Signed-off-by: Roger Quadros <redacted>
---
   .../devicetree/bindings/mfd/omap-usb-host.txt      |   68 ++++++++++++++++
   drivers/mfd/omap-usb-host.c                        |   83 ++++++++++++++++++--
   2 files changed, 145 insertions(+), 6 deletions(-)
   create mode 100644 Documentation/devicetree/bindings/mfd/omap-usb-host.txt

diff --git a/Documentation/devicetree/bindings/mfd/omap-usb-host.txt b/Documentation/devicetree/bindings/mfd/omap-usb-host.txt
new file mode 100644
index 0000000..2196893
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/omap-usb-host.txt

@@ -0,0 +1,68 @@
+OMAP HS USB Host
+
+Required properties:
+
+- compatible: should be "ti,usbhs-host"
+- reg: should contain one register range i.e. start and length
+- ti,hwmods: must contain "usb_host_hs"
+
+Optional properties:
+
+- nports: number of USB ports. Usually this is automatically detected
+  from the IP's revision register but can be overridden by specifying
+  this property.
+
+- portN_mode: Integer specifying the port mode for port N, where N can be
+  from 1 to nports. The port mode must be as per enum usbhs_omap_port_mode
+  in include/linux/platform_data/usb-omap.h
+  If the port mode is not specified, that port is treated as unused.
+
+- single_ulpi_bypass: Must be present if the controller contains a single
+  ULPI bypass control bit. e.g. OMAP3 silicon <= ES2.1
+
+Required properties if child node exists:
+
+- #address-cells: Must be 1
+- #size-cells: Must be 1
+- ranges: must be present
+
+Properties for children:
+
+The OMAP HS USB Host subsystem contains EHCI and OHCI controllers.
+See Documentation/devicetree/bindings/usb/omap-ehci.txt and
+omap3-ohci.txt
+
+Example for OMAP4:
+
+usbhshost: usbhshost at 0x4a064000 {
+    compatible = "ti,usbhs-host";
+    reg = <0x4a064000 0x800>;
+    ti,hwmods = "usb_host_hs";
+    #address-cells = <1>;
+    #size-cells = <1>;
+    ranges;
+
+    usbhsohci: ohci at 0x4a064800 {
+        compatible = "ti,omap3-ohci", "usb-ohci";
+        reg = <0x4a064800 0x400>;
+        interrupt-parent = <&gic>;
+        interrupts = <0 76 0x4>;
+    };
+
+    usbhsehci: ehci at 0x4a064c00 {
+        compatible = "ti,omap-ehci", "usb-ehci";
+        reg = <0x4a064c00 0x400>;
+        interrupt-parent = <&gic>;
+        interrupts = <0 77 0x4>;
+    };
+};
+
+&usbhshost {
+    port1_mode = <1>; /* OMAP_EHCI_PORT_MODE_PHY */
+    port2_mode = <2>; /* OMAP_EHCI_PORT_MODE_TLL */
+    port3_mode = <1>; /* OMAP_EHCI_PORT_MODE_PHY */
+};
+
+&usbhsehci {
+    phy = <&hsusb1_phy 0 &hsusb3_phy>;
+};

diff --git a/drivers/mfd/omap-usb-host.c b/drivers/mfd/omap-usb-host.c
index f8ed08e..0f67856 100644
--- a/drivers/mfd/omap-usb-host.c
+++ b/drivers/mfd/omap-usb-host.c

@@ -1,8 +1,9 @@
   /**
    * omap-usb-host.c - The USBHS core driver for OMAP EHCI & OHCI
    *
- * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com
+ * Copyright (C) 2011-2013 Texas Instruments Incorporated - http://www.ti.com
    * Author: Keshava Munegowda <keshava_mgowda@ti.com>
+ * Author: Roger Quadros <rogerq@ti.com>
    *
    * This program is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License version 2  of

@@ -27,6 +28,8 @@
   #include <linux/platform_device.h>
   #include <linux/platform_data/usb-omap.h>
   #include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>

   #include "omap-usb.h"

@@ -464,6 +467,37 @@ static void omap_usbhs_init(struct device *dev)
       pm_runtime_put_sync(dev);
   }

+static int usbhs_omap_get_dt_pdata(struct device_node *node,
+                    struct usbhs_omap_platform_data *pdata)
+{
+    int ret, i;
+
+    ret = of_property_read_u32(node, "nports", &pdata->nports);
+    if (ret)
+        pdata->nports = 0;
+
+    /* get port modes */
+    for (i = 0; i < OMAP3_HS_USB_PORTS; i++) {
+        char prop[11];
+
+        snprintf(prop, sizeof(prop), "port%d_mode", i + 1);
+        ret = of_property_read_u32(node, prop, &pdata->port_mode[i]);
+        if (ret)
+            pdata->port_mode[i] = OMAP_USBHS_PORT_MODE_UNUSED;
+    }
+
+    /* get flags */
+    pdata->single_ulpi_bypass = of_property_read_bool(node,
+                        "single_ulpi_bypass");
+    return 0;
+}
+
+static struct of_device_id usbhs_child_match_table[] __initdata = {
+    { .compatible = "ti,omap-ehci", },
+    { .compatible = "ti,omap-ohci", },
+    { }
+};
+
   /**
    * usbhs_omap_probe - initialize TI-based HCDs
    *

@@ -479,6 +513,21 @@ static int usbhs_omap_probe(struct platform_device *pdev)
       int                i;
       bool                need_logic_fck;

+    if (dev->of_node) {
+        /* For DT boot we populate platform data from OF node */
+        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+        if (!pdata)
+            return -ENOMEM;
+
+        if (usbhs_omap_get_dt_pdata(dev->of_node, pdata)) {
+            dev_err(dev,
+                "Error getting platform data from DT node\n");
+            return -ENODEV;
+        }
+
+        dev->platform_data = pdata;
+    }
+
       if (!pdata) {
           dev_err(dev, "Missing platform data\n");
           return -ENODEV;

@@ -490,7 +539,7 @@ static int usbhs_omap_probe(struct platform_device *pdev)
           return -ENOMEM;
       }

-    res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "uhh");
+    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
       omap->uhh_base = devm_request_and_ioremap(dev, res);
       if (!omap->uhh_base) {
           dev_err(dev, "Resource request/ioremap failed\n");

@@ -661,10 +710,23 @@ static int usbhs_omap_probe(struct platform_device *pdev)
       }

       omap_usbhs_init(dev);
-    ret = omap_usbhs_alloc_children(pdev);
-    if (ret) {
-        dev_err(dev, "omap_usbhs_alloc_children failed\n");
-        goto err_alloc;
+
+    if (dev->of_node) {
+        ret = of_platform_populate(dev->of_node,
+                usbhs_child_match_table, NULL, dev);
+
+        if (ret) {
+            dev_err(dev, "Failed to create DT children: %d\n", ret);
+            goto err_alloc;
+        }
+
+    } else {
+        ret = omap_usbhs_alloc_children(pdev);
+        if (ret) {
+            dev_err(dev, "omap_usbhs_alloc_children failed: %d\n",
+                        ret);
+            goto err_alloc;
+        }

These child devices should be destroyed on driver remove..no?

I could not find a function that does the opposite of of_platform_populate() or
of_platform_device_create_pdata(). It seems that platform devices created via
device tree are never meant to be destroyed.

No. I've done it for dwc3 in usb/dwc3/dwc3-omap.c. (you can check usb-next)

It kind of makes sense for EHCI/OHCI, cause the devices are always present
on the SoC.

Not true for devices created in drivers/ IMHO. It makes sense only if 
you create the device in some platform specific initialization file.

Also, this driver can't be built as a module so it can never be removed.

Why is this restriction btw?

Thanks
Kishon