Re: [PATCH v12 2/7] mfd: Add driver for ASUS Transformer embedded controller

[Lee Jones]

--- checkpatch.pl (4 issues) ---
Line 607: WARNING: DT compatible string "asus,sl101-ec-dock" appears un-documented -- check ./Documentation/devicetree/bindings/
Line 610: WARNING: DT compatible string "asus,tf101-ec-dock" appears un-documented -- check ./Documentation/devicetree/bindings/
Line 613: WARNING: DT compatible string "asus,tf201-ec-pad" appears un-documented -- check ./Documentation/devicetree/bindings/
Line 616: WARNING: DT compatible string "asus,tf600t-ec-pad" appears un-documented -- check ./Documentation/devicetree/bindings/
----------------------------------

On Mon, 19 Oct 2026, Svyatoslav Ryhel wrote:
> From: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
>
> Support Nuvoton NPCE795-based ECs as used in Asus Transformer TF201,
> TF300T, TF300TG, TF300TL and TF700T pad and dock, as well as TF101 dock
> and TF600T, P1801-T and TF701T pad. This is a glue driver handling
> detection and common operations for EC's functions.
>
> Co-developed-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
> Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> ---
>  drivers/mfd/Kconfig                     |  16 +
>  drivers/mfd/Makefile                    |   1 +
>  drivers/mfd/asus-transformer-ec.c       | 569 ++++++++++++++++++++++++
>  include/linux/mfd/asus-transformer-ec.h | 100 +++++
>  4 files changed, 686 insertions(+)
>  create mode 100644 drivers/mfd/asus-transformer-ec.c
>  create mode 100644 include/linux/mfd/asus-transformer-ec.h

[...]

> +static int asus_ec_reset(struct asus_ec_data *ddata)
> +{
> +	int retry, ret;
> +
> +	guard(mutex)(&ddata->ecreq_lock);
> +
> +	for (retry = 0; retry < ASUSEC_RETRY_MAX; retry++) {

As mentioned on v8, 'for (int retry = 0; ...)' is generally preferred for
throw-away loop variables.

> +		ret = i2c_smbus_write_word_data(ddata->client, ASUSEC_WRITE_BUF,
> +						ASUSEC_RESET);
> +		if (!ret)
> +			return 0;
> +
> +		msleep(ASUSEC_ACCESS_TIMEOUT);
> +	}
> +
> +	return ret;
> +}

[...]

> +static int asus_ec_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct asus_ec_data *ddata;
> +	const struct mfd_cell *cells;
> +	unsigned int num_cells;
> +	unsigned long irqflags;
> +	int ret;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
> +		return dev_err_probe(dev, -ENXIO,
> +			"I2C bus is missing required SMBus block mode support\n");
> +
> +	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
> +	if (!ddata)
> +		return -ENOMEM;
> +
> +	ddata->info = device_get_match_data(dev);
> +	if (!ddata->info)
> +		return -ENODEV;
> +
> +	switch (ddata->info->variant) {
> +	case ASUSEC_SL101_DOCK:
> +		cells = asus_ec_sl101_dock_mfd_devices;
> +		num_cells = ARRAY_SIZE(asus_ec_sl101_dock_mfd_devices);
> +		break;
> +	case ASUSEC_TF101_DOCK:
> +		cells = asus_ec_tf101_dock_mfd_devices;
> +		num_cells = ARRAY_SIZE(asus_ec_tf101_dock_mfd_devices);
> +		break;
> +	case ASUSEC_TF201_PAD:
> +		cells = asus_ec_tf201_pad_mfd_devices;
> +		num_cells = ARRAY_SIZE(asus_ec_tf201_pad_mfd_devices);
> +		break;
> +	case ASUSEC_TF600T_PAD:
> +		cells = asus_ec_tf600t_pad_mfd_devices;
> +		num_cells = ARRAY_SIZE(asus_ec_tf600t_pad_mfd_devices);
> +		break;
> +	default:
> +		return dev_err_probe(dev, -EINVAL,
> +				     "unknown device variant %d\n",
> +				     ddata->info->variant);
> +	}
> +
> +	i2c_set_clientdata(client, ddata);
> +	ddata->client = client;
> +
> +	ddata->ec.dockram = devm_asus_dockram_get(dev);
> +	if (IS_ERR(ddata->ec.dockram))
> +		return dev_err_probe(dev, PTR_ERR(ddata->ec.dockram),
> +				     "failed to get dockram\n");
> +
> +	ddata->ecreq_gpio = devm_gpiod_get(dev, "request", GPIOD_OUT_LOW);
> +	if (IS_ERR(ddata->ecreq_gpio))
> +		return dev_err_probe(dev, PTR_ERR(ddata->ecreq_gpio),
> +				     "failed to get EC request GPIO\n");
> +
> +	BLOCKING_INIT_NOTIFIER_HEAD(&ddata->ec.notify_list);
> +	mutex_init(&ddata->ecreq_lock);
> +
> +	asus_ec_signal_request(ddata);
> +
> +	ret = asus_ec_detect(ddata);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to detect EC version\n");
> +
> +	ret = asus_ec_init(ddata);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to init EC\n");
> +
> +	/*
> +	 * Systems using device tree should set up interrupt via DTS,
> +	 * the rest will use the default low interrupt.
> +	 */
> +	irqflags = dev->of_node ? 0 : IRQF_TRIGGER_LOW;
> +
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
> +					&asus_ec_interrupt,
> +					IRQF_ONESHOT | irqflags,
> +					client->name, ddata);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to register IRQ\n");
> +
> +	/* Parent I2C controller uses DMA, ASUS EC and child devices do not */
> +	client->dev.coherent_dma_mask = 0;
> +	client->dev.dma_mask = &client->dev.coherent_dma_mask;
> +
> +	return devm_mfd_add_devices(dev, 0, cells, num_cells, NULL, 0, NULL);

Why not use 'PLATFORM_DEVID_NONE' or 'PLATFORM_DEVID_AUTO' here instead of a raw
'0' and hard-coded cell IDs in 'asus_ec_tf101_dock_mfd_devices'?

> +}

-- 
Lee Jones