Re: [PATCH v2] platform/x86: intel_cht_int33fe: Work around BIOS bug on some devices

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Sat, 2017-09-02 at 18:20 +0200, Hans de Goede wrote:
> At least one BIOS enumerates the max17047 both through the INT33FE
> ACPI
> device (it is right there in the resources table) as well as through a
> separate MAX17047 device.
> 
> This commit checks for the max17047 already being enumerated through
> a separate MAX17047 ACPI device and if so it uses the i2c-client
> instantiated for this and attaches the device-props for the max17047
> to
> that i2c-client.

This one looks acceptable wrt buggy BIOS workaround, few comments below
(I can do it when applying)

> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> Changes in v2:
> -Check acpi_companion HID instead of dev_name
> ---
>  drivers/platform/x86/intel_cht_int33fe.c | 71
> +++++++++++++++++++++++++++-----
>  1 file changed, 61 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel_cht_int33fe.c
> b/drivers/platform/x86/intel_cht_int33fe.c
> index da706e2c4232..a9cbc4b8ca63 100644
> --- a/drivers/platform/x86/intel_cht_int33fe.c
> +++ b/drivers/platform/x86/intel_cht_int33fe.c
> @@ -34,6 +34,42 @@ struct cht_int33fe_data {
>  	struct i2c_client *pi3usb30532;
>  };
>  
> +/*
> + * Grrr I severly dislike buggy BIOS-es. At least one BIOS enumerates
> + * the max17047 both through the INT33FE ACPI device (it is right
> there
> + * in the resources table) as well as through a separate MAX17047
> device.
> + *
> + * These helpers are used to work around this by checking if an i2c-
> client
> + * for the max17047 has already been registered.
> + */
> +int cht_int33fe_check_for_max17047(struct device *dev, void *data)
> +{
> +	struct acpi_device *companion = ACPI_COMPANION(dev);
> +	struct i2c_client **max17047 = data;
> +	const char *hid;
> +

I would assign companion right here.
> +	if (!companion)
> +		return 0;
> +
> +	hid = acpi_device_hid(companion);
> +
> +	/* The MAX17047 ACPI node doesn't have an UID, so we don't
> check that */

> +	if (strcmp(hid, "MAX17047") == 0) {

if (strcmp())
 return 0;

?

> +		*max17047 = to_i2c_client(dev);
> +		return 1;
> +	}
> +
> +	return 0;
> +}
> +
> +struct i2c_client *cht_int33fe_find_max17047(void)
> +{
> +	struct i2c_client *max17047 = NULL;
> +
> +	i2c_for_each_dev(&max17047, cht_int33fe_check_for_max17047);
> +	return max17047;
> +}
> +
>  static const char * const max17047_suppliers[] = { "bq24190-charger"
> };
>  
>  static const struct property_entry max17047_props[] = {
> @@ -46,9 +82,10 @@ static int cht_int33fe_probe(struct i2c_client
> *client)
>  	struct device *dev = &client->dev;
>  	struct i2c_board_info board_info;
>  	struct cht_int33fe_data *data;
> +	struct i2c_client *max17047;
>  	unsigned long long ptyp;
>  	acpi_status status;
> -	int fusb302_irq;
> +	int ret, fusb302_irq;
>  
>  	status = acpi_evaluate_integer(ACPI_HANDLE(dev), "PTYP",
> NULL, &ptyp);
>  	if (ACPI_FAILURE(status)) {
> @@ -75,13 +112,25 @@ static int cht_int33fe_probe(struct i2c_client
> *client)
>  	if (!data)
>  		return -ENOMEM;
>  
> -	memset(&board_info, 0, sizeof(board_info));
> -	strlcpy(board_info.type, "max17047", I2C_NAME_SIZE);
> -	board_info.properties = max17047_props;
> -
> -	data->max17047 = i2c_acpi_new_device(dev, 1, &board_info);
> -	if (!data->max17047)
> -		return -EPROBE_DEFER; /* Wait for the i2c-adapter to
> load */
> +	/* Work around BIOS bug, see comment on
> cht_int33fe_find_max17047 */
> +	max17047 = cht_int33fe_find_max17047();
> +	if (max17047) {
> +		/* Pre-existing i2c-client for the max17047, add
> device-props */
> +		ret = device_add_properties(&max17047->dev,
> max17047_props);
> +		if (ret)
> +			return ret;
> +		/* And re-probe to get the new device-props applied.
> */
> +		ret = device_reprobe(&max17047->dev);
> +		if (ret)
> +			dev_warn(dev, "Reprobing max17047 error:
> %d\n", ret);
> +	} else {
> +		memset(&board_info, 0, sizeof(board_info));
> +		strlcpy(board_info.type, "max17047", I2C_NAME_SIZE);
> +		board_info.properties = max17047_props;
> +		data->max17047 = i2c_acpi_new_device(dev, 1,
> &board_info);
> +		if (!data->max17047)
> +			return -EPROBE_DEFER; /* Wait for i2c-adapter 
> to load */
> +	}
>  
>  	memset(&board_info, 0, sizeof(board_info));
>  	strlcpy(board_info.type, "fusb302", I2C_NAME_SIZE);
> @@ -106,7 +155,8 @@ static int cht_int33fe_probe(struct i2c_client
> *client)
>  	i2c_unregister_device(data->fusb302);
>  
>  out_unregister_max17047:
> -	i2c_unregister_device(data->max17047);
> +	if (data->max17047)
> +		i2c_unregister_device(data->max17047);
>  
>  	return -EPROBE_DEFER; /* Wait for the i2c-adapter to load */
>  }
> @@ -117,7 +167,8 @@ static int cht_int33fe_remove(struct i2c_client
> *i2c)
>  
>  	i2c_unregister_device(data->pi3usb30532);
>  	i2c_unregister_device(data->fusb302);
> -	i2c_unregister_device(data->max17047);
> +	if (data->max17047)
> +		i2c_unregister_device(data->max17047);
>  
>  	return 0;
>  }

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy