Date:   Mon, 21 May 2018 11:01:37 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Enric Balletbo Serra <eballetbo@...il.com>
Cc:     David Airlie <airlied@...ux.ie>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Lee Jones <lee.jones@...aro.org>,
        Olof Johansson <olof@...om.net>,
        Sean Paul <seanpaul@...gle.com>, sadolfsson@...gle.com,
        intel-gfx@...ts.freedesktop.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Fabien Parent <fparent@...libre.com>,
        Felix Ekblom <felixe@...gle.com>,
        Stéphane Marchesin <marcheu@...omium.org>,
        Benson Leung <bleung@...gle.com>, darekm@...gle.com,
        linux-media@...r.kernel.org
Subject: Re: [PATCH v2 5/5] media: platform: Add Chrome OS EC CEC driver

Hi Enric,

On 18/05/2018 17:02, Enric Balletbo Serra wrote:
> Hi Neil,
> 
> 2018-05-18 15:05 GMT+02:00 Neil Armstrong <narmstrong@...libre.com>:
>> The Chrome OS Embedded Controller can expose a CEC bus, this patch add the
> 
> A minor nit, there is a "consensus" on tell cros-ec as "ChromeOS
> Embedded Controller" or "ChromeOS EC". Yes, I know that you can see in
> the kernel many other ways to refer to the ChromeOS EC, but to
> standardize a little bit, could you replace all occurrences s/Chrome
> OS/ChromeOS/. Thanks.

Ok, I'll do a cleanup.

> 
>> driver for such feature of the Embedded Controller.
>>
>> This driver is part of the cros-ec MFD and will be add as a sub-device when
>> the feature bit is exposed by the EC.
>>
>> The controller will only handle a single logical address and handles
>> all the messages retries and will only expose Success or Error.
>>
>> The controller will be tied to the HDMI CEC notifier by using the platform
>> DMI Data and the i915 device name and connector name.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
>> ---
>>  drivers/media/platform/Kconfig                   |  11 +
>>  drivers/media/platform/Makefile                  |   2 +
>>  drivers/media/platform/cros-ec-cec/Makefile      |   1 +
>>  drivers/media/platform/cros-ec-cec/cros-ec-cec.c | 347 +++++++++++++++++++++++
>>  4 files changed, 361 insertions(+)
>>  create mode 100644 drivers/media/platform/cros-ec-cec/Makefile
>>  create mode 100644 drivers/media/platform/cros-ec-cec/cros-ec-cec.c
>>
>> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
>> index c7a1cf8..e55a8ed2 100644
>> --- a/drivers/media/platform/Kconfig
>> +++ b/drivers/media/platform/Kconfig
>> @@ -546,6 +546,17 @@ menuconfig CEC_PLATFORM_DRIVERS
>>
>>  if CEC_PLATFORM_DRIVERS
>>
>> +config VIDEO_CROS_EC_CEC
>> +       tristate "Chrome OS EC CEC driver"
> 
> here
> 
>> +       depends on MFD_CROS_EC || COMPILE_TEST
>> +       select CEC_CORE
>> +       select CEC_NOTIFIER
>> +       ---help---
>> +         If you say yes here you will get support for the
>> +         Chrome OS Embedded Controller's CEC.
> 
> here
> 
>> +         The CEC bus is present in the HDMI connector and enables communication
>> +         between compatible devices.
>> +
>>  config VIDEO_MESON_AO_CEC
>>         tristate "Amlogic Meson AO CEC driver"
>>         depends on ARCH_MESON || COMPILE_TEST
>> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
>> index 932515d..830696f 100644
>> --- a/drivers/media/platform/Makefile
>> +++ b/drivers/media/platform/Makefile
>> @@ -92,3 +92,5 @@ obj-$(CONFIG_VIDEO_QCOM_CAMSS)                += qcom/camss-8x16/
>>  obj-$(CONFIG_VIDEO_QCOM_VENUS)         += qcom/venus/
>>
>>  obj-y                                  += meson/
>> +
>> +obj-y                                  += cros-ec-cec/
>> diff --git a/drivers/media/platform/cros-ec-cec/Makefile b/drivers/media/platform/cros-ec-cec/Makefile
>> new file mode 100644
>> index 0000000..9ce97f9
>> --- /dev/null
>> +++ b/drivers/media/platform/cros-ec-cec/Makefile
>> @@ -0,0 +1 @@
>> +obj-$(CONFIG_VIDEO_CROS_EC_CEC) += cros-ec-cec.o
>> diff --git a/drivers/media/platform/cros-ec-cec/cros-ec-cec.c b/drivers/media/platform/cros-ec-cec/cros-ec-cec.c
>> new file mode 100644
>> index 0000000..7e1e275
>> --- /dev/null
>> +++ b/drivers/media/platform/cros-ec-cec/cros-ec-cec.c
>> @@ -0,0 +1,347 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * CEC driver for Chrome OS Embedded Controller
> 
> and here
> 
>> + *
>> + * Copyright (c) 2018 BayLibre, SAS
>> + * Author: Neil Armstrong <narmstrong@...libre.com>
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/dmi.h>
>> +#include <linux/pci.h>
>> +#include <linux/cec.h>
>> +#include <linux/slab.h>
>> +#include <linux/interrupt.h>
>> +#include <media/cec.h>
>> +#include <media/cec-notifier.h>
>> +#include <linux/mfd/cros_ec.h>
>> +#include <linux/mfd/cros_ec_commands.h>
>> +
>> +#define DRV_NAME       "cros-ec-cec"
>> +
>> +/**
>> + * struct cros_ec_cec - Driver data for EC CEC
>> + *
>> + * @cros_ec: Pointer to EC device
>> + * @notifier: Notifier info for responding to EC events
>> + * @adap: CEC adapter
>> + * @notify: CEC notifier pointer
>> + * @rx_msg: storage for a received message
>> + */
>> +struct cros_ec_cec {
>> +       struct cros_ec_device *cros_ec;
>> +       struct notifier_block notifier;
>> +       struct cec_adapter *adap;
>> +       struct cec_notifier *notify;
>> +       struct cec_msg rx_msg;
>> +};
>> +
>> +static void handle_cec_message(struct cros_ec_cec *cros_ec_cec)
>> +{
>> +       struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
>> +       uint8_t *cec_message = cros_ec->event_data.data.cec_message;
>> +       unsigned int len = cros_ec->event_size;
>> +
>> +       cros_ec_cec->rx_msg.len = len;
>> +       memcpy(cros_ec_cec->rx_msg.msg, cec_message, len);
>> +
>> +       cec_received_msg(cros_ec_cec->adap, &cros_ec_cec->rx_msg);
>> +}
>> +
>> +static void handle_cec_event(struct cros_ec_cec *cros_ec_cec)
>> +{
>> +       struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
>> +       uint32_t events = cros_ec->event_data.data.cec_events;
>> +
>> +       if (events & EC_MKBP_CEC_SEND_OK)
>> +               cec_transmit_attempt_done(cros_ec_cec->adap,
>> +                                         CEC_TX_STATUS_OK);
>> +
>> +       /* FW takes care of all retries, tell core to avoid more retries */
>> +       if (events & EC_MKBP_CEC_SEND_FAILED)
>> +               cec_transmit_attempt_done(cros_ec_cec->adap,
>> +                                         CEC_TX_STATUS_MAX_RETRIES |
>> +                                         CEC_TX_STATUS_NACK);
>> +}
>> +
>> +static int cros_ec_cec_event(struct notifier_block *nb,
>> +                            unsigned long queued_during_suspend,
>> +                            void *_notify)
>> +{
>> +       struct cros_ec_cec *cros_ec_cec;
>> +       struct cros_ec_device *cros_ec;
>> +
>> +       cros_ec_cec = container_of(nb, struct cros_ec_cec, notifier);
>> +       cros_ec = cros_ec_cec->cros_ec;
>> +
>> +       if (cros_ec->event_data.event_type == EC_MKBP_CEC_EVENT) {
>> +               handle_cec_event(cros_ec_cec);
>> +               return NOTIFY_OK;
>> +       }
>> +
>> +       if (cros_ec->event_data.event_type == EC_MKBP_EVENT_CEC_MESSAGE) {
>> +               handle_cec_message(cros_ec_cec);
>> +               return NOTIFY_OK;
>> +       }
>> +
>> +       return NOTIFY_DONE;
>> +}
>> +
>> +static int cros_ec_cec_set_log_addr(struct cec_adapter *adap, u8 logical_addr)
>> +{
>> +       struct cros_ec_cec *cros_ec_cec = adap->priv;
>> +       struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
>> +       struct {
>> +               struct cros_ec_command msg;
>> +               struct ec_params_cec_set data;
>> +       } __packed msg = {};
>> +       int ret;
>> +
>> +       msg.msg.command = EC_CMD_CEC_SET;
>> +       msg.msg.outsize = sizeof(msg.data);
>> +       msg.data.cmd = CEC_CMD_LOGICAL_ADDRESS;
>> +       msg.data.address = logical_addr;
>> +
>> +       ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
>> +       if (ret < 0) {
>> +               dev_err(cros_ec->dev,
>> +                       "error setting CEC logical address on EC: %d\n", ret);
>> +               return ret;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int cros_ec_cec_transmit(struct cec_adapter *adap, u8 attempts,
>> +                               u32 signal_free_time, struct cec_msg *cec_msg)
>> +{
>> +       struct cros_ec_cec *cros_ec_cec = adap->priv;
>> +       struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
>> +       struct {
>> +               struct cros_ec_command msg;
>> +               struct ec_params_cec_write data;
>> +       } __packed msg = {};
>> +       int ret;
>> +
>> +       msg.msg.command = EC_CMD_CEC_WRITE_MSG;
>> +       msg.msg.outsize = cec_msg->len;
>> +       memcpy(msg.data.msg, cec_msg->msg, cec_msg->len);
>> +
>> +       ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
>> +       if (ret < 0) {
>> +               dev_err(cros_ec->dev,
>> +                       "error writing CEC msg on EC: %d\n", ret);
>> +               return ret;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int cros_ec_cec_adap_enable(struct cec_adapter *adap, bool enable)
>> +{
>> +       struct cros_ec_cec *cros_ec_cec = adap->priv;
>> +       struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
>> +       struct {
>> +               struct cros_ec_command msg;
>> +               struct ec_params_cec_set data;
>> +       } __packed msg = {};
>> +       int ret;
>> +
>> +       msg.msg.command = EC_CMD_CEC_SET;
>> +       msg.msg.outsize = sizeof(msg.data);
>> +       msg.data.cmd = CEC_CMD_ENABLE;
>> +       msg.data.enable = enable;
>> +
>> +       ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
>> +       if (ret < 0) {
>> +               dev_err(cros_ec->dev,
>> +                       "error %sabling CEC on EC: %d\n",
>> +                       (enable ? "en" : "dis"), ret);
>> +               return ret;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct cec_adap_ops cros_ec_cec_ops = {
>> +       .adap_enable = cros_ec_cec_adap_enable,
>> +       .adap_log_addr = cros_ec_cec_set_log_addr,
>> +       .adap_transmit = cros_ec_cec_transmit,
>> +};
>> +
>> +#ifdef CONFIG_PM_SLEEP
>> +static int cros_ec_cec_suspend(struct device *dev)
>> +{
>> +       struct platform_device *pdev = to_platform_device(dev);
>> +       struct cros_ec_cec *cros_ec_cec = dev_get_drvdata(&pdev->dev);
>> +
>> +       if (device_may_wakeup(dev))
>> +               enable_irq_wake(cros_ec_cec->cros_ec->irq);
>> +
>> +       return 0;
>> +}
>> +
>> +static int cros_ec_cec_resume(struct device *dev)
>> +{
>> +       struct platform_device *pdev = to_platform_device(dev);
>> +       struct cros_ec_cec *cros_ec_cec = dev_get_drvdata(&pdev->dev);
>> +
>> +       if (device_may_wakeup(dev))
>> +               disable_irq_wake(cros_ec_cec->cros_ec->irq);
>> +
>> +       return 0;
>> +}
>> +#endif
>> +
>> +static SIMPLE_DEV_PM_OPS(cros_ec_cec_pm_ops,
>> +       cros_ec_cec_suspend, cros_ec_cec_resume);
>> +
>> +#if IS_ENABLED(CONFIG_PCI) && IS_ENABLED(CONFIG_DMI)
>> +
>> +/*
>> + * The Firmware only handles a single CEC interface tied to a single HDMI
>> + * connector we specify along with the DRM device name handling the HDMI output
>> + */
>> +
>> +struct cec_dmi_match {
>> +       char *sys_vendor;
>> +       char *product_name;
>> +       char *devname;
>> +       char *conn;
>> +};
>> +
>> +static const struct cec_dmi_match cec_dmi_match_table[] = {
>> +       /* Google Fizz */
>> +       { "Google", "Fizz", "0000:00:02.0", "Port B" },
>> +};
>> +
>> +static int cros_ec_cec_get_notifier(struct device *dev,
>> +                                   struct cec_notifier **notify)
>> +{
>> +       int i;
>> +
>> +       for (i = 0 ; i < ARRAY_SIZE(cec_dmi_match_table) ; ++i) {
>> +               const struct cec_dmi_match *m = &cec_dmi_match_table[i];
>> +
>> +               if (dmi_match(DMI_SYS_VENDOR, m->sys_vendor) &&
>> +                   dmi_match(DMI_PRODUCT_NAME, m->product_name)) {
>> +                       struct device *d;
>> +
>> +                       /* Find the device, bail out if not yet registered */
>> +                       d = bus_find_device_by_name(&pci_bus_type, NULL,
>> +                                                   m->devname);
>> +                       if (!d)
>> +                               return -EPROBE_DEFER;
>> +
>> +                       *notify = cec_notifier_get_conn(d, m->conn);
>> +                       return 0;
>> +               }
>> +       }
>> +
>> +       /* Hardware support must be added in the cec_dmi_match_table */
>> +       dev_warn(dev, "CEC notifier not configured for this hardware\n");
>> +
>> +       return -ENODEV;
>> +}
>> +
>> +#else
>> +
>> +static int cros_ec_cec_get_notifier(struct device *dev,
>> +                                   struct cec_notifier **notify)
>> +{
>> +       return -ENODEV;
>> +}
>> +
>> +#endif
>> +
>> +static int cros_ec_cec_probe(struct platform_device *pdev)
>> +{
>> +       struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
>> +       struct cros_ec_device *cros_ec = ec_dev->ec_dev;
>> +       struct cros_ec_cec *cros_ec_cec;
>> +       int ret;
>> +
>> +       cros_ec_cec = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_cec),
>> +                                  GFP_KERNEL);
>> +       if (!cros_ec_cec)
>> +               return -ENOMEM;
>> +
>> +       platform_set_drvdata(pdev, cros_ec_cec);
>> +       cros_ec_cec->cros_ec = cros_ec;
>> +
>> +       ret = cros_ec_cec_get_notifier(&pdev->dev, &cros_ec_cec->notify);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = device_init_wakeup(&pdev->dev, 1);
>> +       if (ret) {
>> +               dev_err(&pdev->dev, "failed to initialize wakeup\n");
>> +               return ret;
>> +       }
>> +
>> +       cros_ec_cec->adap = cec_allocate_adapter(&cros_ec_cec_ops, cros_ec_cec,
>> +                                                DRV_NAME, CEC_CAP_DEFAULTS, 1);
>> +       if (IS_ERR(cros_ec_cec->adap))
>> +               return PTR_ERR(cros_ec_cec->adap);
>> +
>> +       /* Get CEC events from the EC. */
>> +       cros_ec_cec->notifier.notifier_call = cros_ec_cec_event;
>> +       ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
>> +                                              &cros_ec_cec->notifier);
>> +       if (ret) {
>> +               dev_err(&pdev->dev, "failed to register notifier\n");
>> +               cec_delete_adapter(cros_ec_cec->adap);
>> +               return ret;
>> +       }
>> +
>> +       ret = cec_register_adapter(cros_ec_cec->adap, &pdev->dev);
>> +       if (ret < 0) {
>> +               cec_delete_adapter(cros_ec_cec->adap);
>> +               return ret;
>> +       }
>> +
>> +       cec_register_cec_notifier(cros_ec_cec->adap, cros_ec_cec->notify);
>> +
>> +       return 0;
>> +}
>> +
>> +static int cros_ec_cec_remove(struct platform_device *pdev)
>> +{
>> +       struct cros_ec_cec *cros_ec_cec = platform_get_drvdata(pdev);
>> +       struct device *dev = &pdev->dev;
>> +       int ret;
>> +
>> +       ret = blocking_notifier_chain_unregister(
>> +                       &cros_ec_cec->cros_ec->event_notifier,
>> +                       &cros_ec_cec->notifier);
>> +
>> +       if (ret) {
>> +               dev_err(dev, "failed to unregister notifier\n");
>> +               return ret;
>> +       }
>> +
>> +       cec_unregister_adapter(cros_ec_cec->adap);
>> +
>> +       if (cros_ec_cec->notify)
>> +               cec_notifier_put(cros_ec_cec->notify);
>> +
>> +       return 0;
>> +}
>> +
>> +static struct platform_driver cros_ec_cec_driver = {
>> +       .probe = cros_ec_cec_probe,
>> +       .remove  = cros_ec_cec_remove,
>> +       .driver = {
>> +               .name = DRV_NAME,
>> +               .pm = &cros_ec_cec_pm_ops,
>> +       },
>> +};
>> +
>> +module_platform_driver(cros_ec_cec_driver);
>> +
>> +MODULE_DESCRIPTION("CEC driver for Chrome OS ECs");
>> +MODULE_AUTHOR("Neil Armstrong <narmstrong@...libre.com>");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:" DRV_NAME);
>> --
>> 2.7.4
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@...ts.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> The patch looks good to me, so
> 
> Reviewed-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> 

Thanks,
Neil

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