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SubjectRe: [PATCH] HID: i2c-hid: Use device properties (instead of device tree)
On Fri, Sep 29, 2017 at 5:08 PM, Brian Norris <briannorris@chromium.org> wrote:
> Hi Rajat,
>
> On Fri, Sep 29, 2017 at 03:44:41PM -0700, Rajat Jain wrote:
>> Use the device properties (that can be provided by ACPI systems
>> as well as non ACPI systems) instead of device tree properties
>> (that are not provided ACPI systems). This required some minor
>> code restructuring.
>>
>> Signed-off-by: Rajat Jain <rajatja@google.com>
>> ---
>> I don't think its a big deal, but just FYI, this changes the order in which we
>> look for HID register address from
>> (device tree -> platform_data -> ACPI) to
>> (platform data -> device tree -> ACPI)
>>
>> drivers/hid/i2c-hid/i2c-hid.c | 44 ++++++++++++++-----------------------------
>> 1 file changed, 14 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
>> index 77396145d2d0..718afceb2395 100644
>> --- a/drivers/hid/i2c-hid/i2c-hid.c
>> +++ b/drivers/hid/i2c-hid/i2c-hid.c
>> @@ -908,45 +908,36 @@ static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
>> static inline void i2c_hid_acpi_fix_up_power(struct device *dev) {}
>> #endif
>>
>> -#ifdef CONFIG_OF
>> -static int i2c_hid_of_probe(struct i2c_client *client,
>> +static int i2c_hid_fwnode_probe(struct i2c_client *client,
>> struct i2c_hid_platform_data *pdata)
>> {
>> struct device *dev = &client->dev;
>> u32 val;
>> int ret;
>>
>> - ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
>> - if (ret) {
>> - dev_err(&client->dev, "HID register address not provided\n");
>> - return -ENODEV;
>> - }
>> - if (val >> 16) {
>> - dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
>> - val);
>> - return -EINVAL;
>> + ret = device_property_read_u32(dev, "hid-descr-addr", &val);
>> + if (ret || val >> 16) {
>
> We used to reject a bad addr with -EINVAL. Now we retry with ACPI. Is
> that reasonable? I'd think you should just reject a bad value.
>
>> + /* Couldn't read using fwnode, try ACPI next */
>> + if (!i2c_hid_acpi_pdata(client, pdata)) {
>
> I think the '!' negation is wrong. Returning 0 is success.
>
>> + dev_err(dev, "Bad/Not provided HID register address\n");
>> + return -ENODEV;
>
> This should propagate the error code from i2c_hid_acpi_pdata().
>
>> + }
>> }
>> pdata->hid_descriptor_address = val;
>
> This will break ACPI (with no device property) now; i2c_hid_acpi_pdata()
> can parse one value, but then you'll clobber it here with some junk
> ('val' is potentially uninitialized in the ACPI case).
>
>>
>> - ret = of_property_read_u32(dev->of_node, "post-power-on-delay-ms",
>> - &val);
>> + ret = device_property_read_u32(dev, "post-power-on-delay-ms", &val);
>> if (!ret)
>> pdata->post_power_delay_ms = val;
>>
>> return 0;
>> }
>>
>> +#ifdef CONFIG_OF
>> static const struct of_device_id i2c_hid_of_match[] = {
>> { .compatible = "hid-over-i2c" },
>> {},
>> };
>> MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
>> -#else
>> -static inline int i2c_hid_of_probe(struct i2c_client *client,
>> - struct i2c_hid_platform_data *pdata)
>> -{
>> - return -ENODEV;
>> -}
>> #endif
>>
>> static int i2c_hid_probe(struct i2c_client *client,
>> @@ -977,19 +968,12 @@ static int i2c_hid_probe(struct i2c_client *client,
>> if (!ihid)
>> return -ENOMEM;
>>
>> - if (client->dev.of_node) {
>> - ret = i2c_hid_of_probe(client, &ihid->pdata);
>> + if (platform_data) {
>> + ihid->pdata = *platform_data;
>> + } else if (dev_fwnode(&client->dev)) {
>> + ret = i2c_hid_fwnode_probe(client, &ihid->pdata);
>> if (ret)
>> goto err;
>> - } else if (!platform_data) {
>> - ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
>> - if (ret) {
>> - dev_err(&client->dev,
>> - "HID register address not provided\n");
>> - goto err;
>> - }
>> - } else {
>> - ihid->pdata = *platform_data;
>> }
>
> Where's the 'else' case now? Presumably there's some case where you have
> neither platform_data nor dev_fwnode() (I actually don't know much
> about non-device tree fwnodes -- do all ACPI systems have them now?)
>
> Anyway, I'd think you should have at least an error in the 'else' case
> now.


Thanks Brian for the review. Based on Andy's review, I think it might
be more acceptable to just read the property post-power-on-delay
property in the i2c_hid_acpi_pdata(), and thus not change anything
else. So please allow me to send another patch, that should hopefully
not raise the concerns that you raised.

Thanks,
Rajat

>
> Brian
>
>>
>> ihid->pdata.supply = devm_regulator_get(&client->dev, "vdd");
>> --
>> 2.14.2.822.g60be5d43e6-goog
>>

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