Re: [PATCH] input: joystick: Adding Austria Microsystem AS5011 joystick driver (second version)

Fabien Marteau
2010-12-31T11:38:17Z

Hi Trilok,

>
>> + int ret;
>> +
>> + mutex_lock(&plat_dat->button_lock);
>> + ret = gpio_get_value(plat_dat->button_gpio);
>> + if (ret)
>> + input_report_key(plat_dat->input_dev, BTN_JOYSTICK, 0);
>> + else
>> + input_report_key(plat_dat->input_dev, BTN_JOYSTICK, 1);
>> + input_sync(plat_dat->input_dev);
>> + mutex_unlock(&plat_dat->button_lock);
>
> Do you need this lock? Please explain.

If gpio_get_value() sleep, I need it to avoid race condition.

>> +static int as5011_i2c_write(struct i2c_client *client,
>> + uint8_t aRegAddr,
>> + uint8_t aValue)
>> +{
>> + int ret;
>> + uint8_t data[2] = { aRegAddr, aValue };
>
> No CamelCases please. Please run scripts/checkpatch.pl on your patch before submission.

I had no warning for CamelCases name.

>> +static int __devinit as5011_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct as5011_platform_data *plat_dat = client->dev.platform_data;
>> + int retval = 0;
>> +
>> + plat_dat->num = g_num;
>> + g_num++;
>
> What is g_num++ and why it has to be global?

It's for interruptions name, if several as5011 joystick I set a number different for each joystick :

scnprintf(plat_dat->button_irq_name,
SIZE_NAME,
"as5011_%d_button",
plat_dat->num);
>
>> +
>> + if (!i2c_check_functionality(client->adapter,
>> + I2C_FUNC_PROTOCOL_MANGLING)) {
>
> Please explain why MANGLING required.

It's required for i2c register reading. To read register as5011 chip use this i2c frames :
S Addr Rd [A] Register_addr [A] [Data] NA P
Wich is not conform to i2c protocol, i2c protocol require a repeated start to do that :
S Addr Wr [A] Register_addr [A] S Addr Rd [Data] NA P

Then protocol mangling capability is required to avoid repeated start.

>> + int (*init_gpio)(void); /* init interrupts gpios */
>> + void (*exit_gpio)(void);/* exit gpios */
>
> You should better do gpio_request/free etc, in the driver itself,
> and anyother thing can be left out in these hooks.

Yes, but on my platform, requesting gpio are specific. And I have to configure irq edge on initialization :
static int as5011_init_gpio(void)
{
int ret;

ret = mxc_gpio_setup_multiple_pins(as5011_pins0,
ARRAY_SIZE(as5011_pins0),
"AS5011_0");
if (ret < 0) {
goto as5011_gpio_setup_error;
}
set_irq_type(AS5011_INT_IRQ, IRQ_TYPE_EDGE_FALLING);
set_irq_type(AS5011_BUTTON_IRQ, IRQ_TYPE_EDGE_BOTH);
return ret;

mxc_gpio_release_multiple_pins(as5011_pins0, ARRAY_SIZE(as5011_pins0));
as5011_gpio_setup_error:
return ret;
}

> ---Trilok Soni
Thanks for the review.

--- Fabien Marteau