mfd / platform: cros_ec: Handle chained ECs as platform devices

An MFD is a device that contains several sub-devices (cells). For instance,
the ChromeOS EC fits in this description as usually contains a charger and
can have other devices with different functions like a Real-Time Clock,
an Audio codec, a Real-Time Clock, ...

If you look at the driver, though, we're doing something odd. We have
two MFD cros-ec drivers where one of them (cros-ec-core) instantiates
another MFD driver as sub-driver (cros-ec-dev), and the latest
instantiates the different sub-devices (Real-Time Clock, Audio codec,
etc).

                  MFD
------------------------------------------
   cros-ec-core
       |___ mfd-cellA (cros-ec-dev)
       |       |__ mfd-cell0
       |       |__ mfd-cell1
       |       |__ ...
       |
       |___ mfd-cellB (cros-ec-dev)
               |__ mfd-cell0
               |__ mfd-cell1
               |__ ...

The problem that was trying to solve is to describe some kind of topology for
the case where we have an EC (cros-ec) chained with another EC
(cros-pd). Apart from that this extends the bounds of what MFD was
designed to do we might be interested on have other kinds of topology that
can't be implemented in that way.

Let's prepare the code to move the cros-ec-core part from MFD to
platform/chrome as this is clearly a platform specific thing non-related
to a MFD device.

  platform/chrome  |         MFD
------------------------------------------
                   |
   cros-ec ________|___ cros-ec-dev
                   |       |__ mfd-cell0
                   |       |__ mfd-cell1
                   |       |__ ...
                   |
   cros-pd ________|___ cros-ec-dev
                   |        |__ mfd-cell0
                   |        |__ mfd-cell1
                   |        |__ ...

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index 2a9ac5213893ad435c2a5b1cb6ed6e0de85a614a..a54ad47c7b02ccc47125579cf010973df18db0a8 100644 (file)
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -13,7 +13,6 @@
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/mfd/core.h>
 #include <linux/mfd/cros_ec.h>
 #include <linux/suspend.h>
 #include <asm/unaligned.h>
@@ -31,18 +30,6 @@ static struct cros_ec_platform pd_p = {
        .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
 };
 
-static const struct mfd_cell ec_cell = {
-       .name = "cros-ec-dev",
-       .platform_data = &ec_p,
-       .pdata_size = sizeof(ec_p),
-};
-
-static const struct mfd_cell ec_pd_cell = {
-       .name = "cros-ec-dev",
-       .platform_data = &pd_p,
-       .pdata_size = sizeof(pd_p),
-};
-
 static irqreturn_t ec_irq_thread(int irq, void *data)
 {
        struct cros_ec_device *ec_dev = data;
@@ -154,38 +141,42 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
                }
        }
 
-       err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO, &ec_cell,
-                                  1, NULL, ec_dev->irq, NULL);
-       if (err) {
-               dev_err(dev,
-                       "Failed to register Embedded Controller subdevice %d\n",
-                       err);
-               return err;
+       /* Register a platform device for the main EC instance */
+       ec_dev->ec = platform_device_register_data(ec_dev->dev, "cros-ec-dev",
+                                       PLATFORM_DEVID_AUTO, &ec_p,
+                                       sizeof(struct cros_ec_platform));
+       if (IS_ERR(ec_dev->ec)) {
+               dev_err(ec_dev->dev,
+                       "Failed to create CrOS EC platform device\n");
+               return PTR_ERR(ec_dev->ec);
        }
 
        if (ec_dev->max_passthru) {
                /*
-                * Register a PD device as well on top of this device.
+                * Register a platform device for the PD behind the main EC.
                 * We make the following assumptions:
                 * - behind an EC, we have a pd
                 * - only one device added.
                 * - the EC is responsive at init time (it is not true for a
-                *   sensor hub.
+                *   sensor hub).
                 */
-               err = devm_mfd_add_devices(ec_dev->dev, PLATFORM_DEVID_AUTO,
-                                     &ec_pd_cell, 1, NULL, ec_dev->irq, NULL);
-               if (err) {
-                       dev_err(dev,
-                               "Failed to register Power Delivery subdevice %d\n",
-                               err);
-                       return err;
+               ec_dev->pd = platform_device_register_data(ec_dev->dev,
+                                       "cros-ec-dev",
+                                       PLATFORM_DEVID_AUTO, &pd_p,
+                                       sizeof(struct cros_ec_platform));
+               if (IS_ERR(ec_dev->pd)) {
+                       dev_err(ec_dev->dev,
+                               "Failed to create CrOS PD platform device\n");
+                       platform_device_unregister(ec_dev->ec);
+                       return PTR_ERR(ec_dev->pd);
                }
        }
 
        if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
                err = devm_of_platform_populate(dev);
                if (err) {
-                       mfd_remove_devices(dev);
+                       platform_device_unregister(ec_dev->pd);
+                       platform_device_unregister(ec_dev->ec);
                        dev_err(dev, "Failed to register sub-devices\n");
                        return err;
                }
@@ -206,6 +197,16 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 }
 EXPORT_SYMBOL(cros_ec_register);
 
+int cros_ec_unregister(struct cros_ec_device *ec_dev)
+{
+       if (ec_dev->pd)
+               platform_device_unregister(ec_dev->pd);
+       platform_device_unregister(ec_dev->ec);
+
+       return 0;
+}
+EXPORT_SYMBOL(cros_ec_unregister);
+
 #ifdef CONFIG_PM_SLEEP
 int cros_ec_suspend(struct cros_ec_device *ec_dev)
 {

diff --git a/drivers/platform/chrome/cros_ec_i2c.c b/drivers/platform/chrome/cros_ec_i2c.c
index 61d75395f86d802c3ad9638e2520bcee863b2440..6bb82dfa7dae8aa1e98288ecd66331027fcc381b 100644 (file)
--- a/drivers/platform/chrome/cros_ec_i2c.c
+++ b/drivers/platform/chrome/cros_ec_i2c.c
@@ -307,6 +307,13 @@ static int cros_ec_i2c_probe(struct i2c_client *client,
        return 0;
 }
 
+static int cros_ec_i2c_remove(struct i2c_client *client)
+{
+       struct cros_ec_device *ec_dev = i2c_get_clientdata(client);
+
+       return cros_ec_unregister(ec_dev);
+}
+
 #ifdef CONFIG_PM_SLEEP
 static int cros_ec_i2c_suspend(struct device *dev)
 {
@@ -357,6 +364,7 @@ static struct i2c_driver cros_ec_driver = {
                .pm     = &cros_ec_i2c_pm_ops,
        },
        .probe          = cros_ec_i2c_probe,
+       .remove         = cros_ec_i2c_remove,
        .id_table       = cros_ec_i2c_id,
 };
 

diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 2c44c7f3322a395f3dc9ecd4c116402059c39937..5939c4a5869cb28874dcc326e8746b17fee0bf99 100644 (file)
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -421,6 +421,7 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 
 static int cros_ec_lpc_remove(struct platform_device *pdev)
 {
+       struct cros_ec_device *ec_dev = platform_get_drvdata(pdev);
        struct acpi_device *adev;
 
        adev = ACPI_COMPANION(&pdev->dev);
@@ -428,7 +429,7 @@ static int cros_ec_lpc_remove(struct platform_device *pdev)
                acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
                                           cros_ec_lpc_acpi_notify);
 
-       return 0;
+       return cros_ec_unregister(ec_dev);
 }
 
 static const struct acpi_device_id cros_ec_lpc_acpi_device_ids[] = {

diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c
index 5d3fb2abad1d6116247465e460fa8bbab47bd4ec..520e507bfa54e16f7824233d3ebf55e73085a1e2 100644 (file)
--- a/drivers/platform/chrome/cros_ec_rpmsg.c
+++ b/drivers/platform/chrome/cros_ec_rpmsg.c
@@ -233,6 +233,8 @@ static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
        struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
        struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
 
+       cros_ec_unregister(ec_dev);
+
        cancel_work_sync(&ec_rpmsg->host_event_work);
 }
 

diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
index 006a8ff640573fa56e42a9c421cfd8f6664f5cd4..2e21f2776063717e8ded26e22bbfeebb14977dc4 100644 (file)
--- a/drivers/platform/chrome/cros_ec_spi.c
+++ b/drivers/platform/chrome/cros_ec_spi.c
@@ -785,6 +785,13 @@ static int cros_ec_spi_probe(struct spi_device *spi)
        return 0;
 }
 
+static int cros_ec_spi_remove(struct spi_device *spi)
+{
+       struct cros_ec_device *ec_dev = spi_get_drvdata(spi);
+
+       return cros_ec_unregister(ec_dev);
+}
+
 #ifdef CONFIG_PM_SLEEP
 static int cros_ec_spi_suspend(struct device *dev)
 {
@@ -823,6 +830,7 @@ static struct spi_driver cros_ec_driver_spi = {
                .pm     = &cros_ec_spi_pm_ops,
        },
        .probe          = cros_ec_spi_probe,
+       .remove         = cros_ec_spi_remove,
        .id_table       = cros_ec_spi_id,
 };
 

diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 77805c3f2de713b7ce6f02748e0161efa93a4664..bcccda0257ff2f0c33b2e54da5e7c78145ef7c0d 100644 (file)
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -121,6 +121,10 @@ struct cros_ec_command {
  * @event_data: Raw payload transferred with the MKBP event.
  * @event_size: Size in bytes of the event data.
  * @host_event_wake_mask: Mask of host events that cause wake from suspend.
+ * @ec: The platform_device used by the mfd driver to interface with the
+ *      main EC.
+ * @pd: The platform_device used by the mfd driver to interface with the
+ *      PD behind an EC.
  */
 struct cros_ec_device {
        /* These are used by other drivers that want to talk to the EC */
@@ -157,6 +161,10 @@ struct cros_ec_device {
        int event_size;
        u32 host_event_wake_mask;
        u32 last_resume_result;
+
+       /* The platform devices used by the mfd driver */
+       struct platform_device *ec;
+       struct platform_device *pd;
 };
 
 /**
@@ -291,6 +299,16 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
  */
 int cros_ec_register(struct cros_ec_device *ec_dev);
 
+/**
+ * cros_ec_unregister() - Remove a ChromeOS EC.
+ * @ec_dev: Device to unregister.
+ *
+ * Call this to deregister a ChromeOS EC, then clean up any private data.
+ *
+ * Return: 0 on success or negative error code.
+ */
+int cros_ec_unregister(struct cros_ec_device *ec_dev);
+
 /**
  * cros_ec_query_all() -  Query the protocol version supported by the
  *         ChromeOS EC.