Bluetooth: hci_bcm: Add PM for BCM devices

Retrieve "shutdown" and "device_wakeup" GPIOs from ACPI.
Set device off during platform device enumeration.
Set device on only when attached.
As driver can be unbound we need to check if the bcm_device still exists
before calling GPIO's functions, this is protected using device_list_lock.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 23523e140a9a11ef29e08541782e3d8627dca221..6ac66364684d07744bf99d149896b539f9df913f 100644 (file)
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -25,6 +25,12 @@
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/gpio/consumer.h>
+#include <linux/tty.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -32,11 +38,30 @@
 #include "btbcm.h"
 #include "hci_uart.h"
 
+struct bcm_device {
+       struct list_head        list;
+
+       struct platform_device  *pdev;
+
+       const char              *name;
+       struct gpio_desc        *device_wakeup;
+       struct gpio_desc        *shutdown;
+
+       struct clk              *clk;
+       bool                    clk_enabled;
+};
+
 struct bcm_data {
-       struct sk_buff *rx_skb;
-       struct sk_buff_head txq;
+       struct sk_buff          *rx_skb;
+       struct sk_buff_head     txq;
+
+       struct bcm_device       *dev;
 };
 
+/* List of BCM BT UART devices */
+static DEFINE_SPINLOCK(bcm_device_list_lock);
+static LIST_HEAD(bcm_device_list);
+
 static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
 {
        struct hci_dev *hdev = hu->hdev;
@@ -86,9 +111,41 @@ static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
        return 0;
 }
 
+/* bcm_device_exists should be protected by bcm_device_list_lock */
+static bool bcm_device_exists(struct bcm_device *device)
+{
+       struct list_head *p;
+
+       list_for_each(p, &bcm_device_list) {
+               struct bcm_device *dev = list_entry(p, struct bcm_device, list);
+
+               if (device == dev)
+                       return true;
+       }
+
+       return false;
+}
+
+static int bcm_gpio_set_power(struct bcm_device *dev, bool powered)
+{
+       if (powered && !IS_ERR(dev->clk) && !dev->clk_enabled)
+               clk_enable(dev->clk);
+
+       gpiod_set_value_cansleep(dev->shutdown, powered);
+       gpiod_set_value_cansleep(dev->device_wakeup, powered);
+
+       if (!powered && !IS_ERR(dev->clk) && dev->clk_enabled)
+               clk_disable(dev->clk);
+
+       dev->clk_enabled = powered;
+
+       return 0;
+}
+
 static int bcm_open(struct hci_uart *hu)
 {
        struct bcm_data *bcm;
+       struct list_head *p;
 
        BT_DBG("hu %p", hu);
 
@@ -99,6 +156,26 @@ static int bcm_open(struct hci_uart *hu)
        skb_queue_head_init(&bcm->txq);
 
        hu->priv = bcm;
+
+       spin_lock(&bcm_device_list_lock);
+       list_for_each(p, &bcm_device_list) {
+               struct bcm_device *dev = list_entry(p, struct bcm_device, list);
+
+               /* Retrieve saved bcm_device based on parent of the
+                * platform device (saved during device probe) and
+                * parent of tty device used by hci_uart
+                */
+               if (hu->tty->dev->parent == dev->pdev->dev.parent) {
+                       bcm->dev = dev;
+                       break;
+               }
+       }
+
+       if (bcm->dev)
+               bcm_gpio_set_power(bcm->dev, true);
+
+       spin_unlock(&bcm_device_list_lock);
+
        return 0;
 }
 
@@ -108,6 +185,12 @@ static int bcm_close(struct hci_uart *hu)
 
        BT_DBG("hu %p", hu);
 
+       /* Protect bcm->dev against removal of the device or driver */
+       spin_lock(&bcm_device_list_lock);
+       if (bcm_device_exists(bcm->dev))
+               bcm_gpio_set_power(bcm->dev, false);
+       spin_unlock(&bcm_device_list_lock);
+
        skb_queue_purge(&bcm->txq);
        kfree_skb(bcm->rx_skb);
        kfree(bcm);
@@ -232,6 +315,113 @@ static struct sk_buff *bcm_dequeue(struct hci_uart *hu)
        return skb_dequeue(&bcm->txq);
 }
 
+static const struct acpi_gpio_params device_wakeup_gpios = { 0, 0, false };
+static const struct acpi_gpio_params shutdown_gpios = { 1, 0, false };
+
+static const struct acpi_gpio_mapping acpi_bcm_default_gpios[] = {
+       { "device-wakeup-gpios", &device_wakeup_gpios, 1 },
+       { "shutdown-gpios", &shutdown_gpios, 1 },
+       { },
+};
+
+static int bcm_acpi_probe(struct bcm_device *dev)
+{
+       struct platform_device *pdev = dev->pdev;
+       const struct acpi_device_id *id;
+       struct gpio_desc *gpio;
+       int ret;
+
+       id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
+       if (!id)
+               return -ENODEV;
+
+       /* Retrieve GPIO data */
+       dev->name = dev_name(&pdev->dev);
+       ret = acpi_dev_add_driver_gpios(ACPI_COMPANION(&pdev->dev),
+                                       acpi_bcm_default_gpios);
+       if (ret)
+               return ret;
+
+       dev->clk = devm_clk_get(&pdev->dev, NULL);
+
+       gpio = devm_gpiod_get(&pdev->dev, "device-wakeup");
+       if (!IS_ERR(gpio)) {
+               ret = gpiod_direction_output(gpio, 0);
+               if (ret)
+                       return ret;
+               dev->device_wakeup = gpio;
+       }
+
+       gpio = devm_gpiod_get(&pdev->dev, "shutdown");
+       if (!IS_ERR(gpio)) {
+               ret = gpiod_direction_output(gpio, 0);
+               if (ret)
+                       return ret;
+               dev->shutdown = gpio;
+       }
+
+       /* Make sure at-least one of the GPIO is defined and that
+        * a name is specified for this instance
+        */
+       if ((!dev->device_wakeup && !dev->shutdown) || !dev->name) {
+               dev_err(&pdev->dev, "invalid platform data\n");
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int bcm_probe(struct platform_device *pdev)
+{
+       struct bcm_device *dev;
+       struct acpi_device_id *pdata = pdev->dev.platform_data;
+       int ret;
+
+       dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+       if (!dev)
+               return -ENOMEM;
+
+       dev->pdev = pdev;
+
+       if (ACPI_HANDLE(&pdev->dev)) {
+               ret = bcm_acpi_probe(dev);
+               if (ret)
+                       return ret;
+       } else if (pdata) {
+               dev->name = pdata->id;
+       } else {
+               return -ENODEV;
+       }
+
+       platform_set_drvdata(pdev, dev);
+
+       dev_info(&pdev->dev, "%s device registered.\n", dev->name);
+
+       /* Place this instance on the device list */
+       spin_lock(&bcm_device_list_lock);
+       list_add_tail(&dev->list, &bcm_device_list);
+       spin_unlock(&bcm_device_list_lock);
+
+       bcm_gpio_set_power(dev, false);
+
+       return 0;
+}
+
+static int bcm_remove(struct platform_device *pdev)
+{
+       struct bcm_device *dev = platform_get_drvdata(pdev);
+
+       spin_lock(&bcm_device_list_lock);
+       list_del(&dev->list);
+       spin_unlock(&bcm_device_list_lock);
+
+       acpi_dev_remove_driver_gpios(ACPI_COMPANION(&pdev->dev));
+
+       dev_info(&pdev->dev, "%s device unregistered.\n", dev->name);
+
+       return 0;
+}
+
 static const struct hci_uart_proto bcm_proto = {
        .id             = HCI_UART_BCM,
        .name           = "BCM",
@@ -247,12 +437,34 @@ static const struct hci_uart_proto bcm_proto = {
        .dequeue        = bcm_dequeue,
 };
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id bcm_acpi_match[] = {
+       { "BCM2E39", 0 },
+       { "BCM2E67", 0 },
+       { },
+};
+MODULE_DEVICE_TABLE(acpi, bcm_acpi_match);
+#endif
+
+static struct platform_driver bcm_driver = {
+       .probe = bcm_probe,
+       .remove = bcm_remove,
+       .driver = {
+               .name = "hci_bcm",
+               .acpi_match_table = ACPI_PTR(bcm_acpi_match),
+       },
+};
+
 int __init bcm_init(void)
 {
+       platform_driver_register(&bcm_driver);
+
        return hci_uart_register_proto(&bcm_proto);
 }
 
 int __exit bcm_deinit(void)
 {
+       platform_driver_unregister(&bcm_driver);
+
        return hci_uart_unregister_proto(&bcm_proto);
 }