Hello Alexandre-
Few comments below.
On Sat, Sep 26, 2015 at 03:54:39PM +0200, Alexandre Belloni wrote:
> This driver supports the following functions:
> - reading and settings time
> - alarms when connected to an IRQ
> - reading and clearing the voltage low flags
> - nvram
>
> Signed-off-by: Alexandre Belloni <alexandre.bell...@free-electrons.com>
> ---
[..]
> +static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
> +{
> + struct i2c_client *client = dev_id;
> + struct rv8803_data *rv8803 = i2c_get_clientdata(client);
> + unsigned long events = 0;
> + u8 flags;
> +
> + flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
> + if (flags <= 0)
> + return IRQ_HANDLED;
Returning IRQ_HANDLED when no interrupt condition is met. That seems
like a bad idea.
> + if (flags & RV8803_FLAG_V1F)
> + dev_warn(&client->dev, "Voltage low, temperature compensation
> stopped.\n");
> +
> + if (flags & RV8803_FLAG_V2F)
> + dev_warn(&client->dev, "Voltage low, data loss detected.\n");
> +
> + if (flags & RV8803_FLAG_TF) {
> + flags &= ~RV8803_FLAG_TF;
> + rv8803->ctrl &= ~RV8803_CTRL_TIE;
> + events |= RTC_PF;
> + }
> +
> + if (flags & RV8803_FLAG_AF) {
> + flags &= ~RV8803_FLAG_AF;
> + rv8803->ctrl &= ~RV8803_CTRL_AIE;
> + events |= RTC_AF;
> + }
> +
> + if (flags & RV8803_FLAG_UF) {
> + flags &= ~RV8803_FLAG_UF;
> + rv8803->ctrl &= ~RV8803_CTRL_UIE;
> + events |= RTC_UF;
> + }
> +
> + if (events) {
> + rtc_update_irq(rv8803->rtc, 1, events);
> + i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
How are the many read-modify-write cycles for flags safe without any
form of synchronization? (Especially given the interrupt handler isn't
under ops_lock).
> + i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
> + rv8803->ctrl);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
[..]
> +static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> + struct rv8803_data *rv8803 = dev_get_drvdata(dev);
> + struct i2c_client *client = rv8803->client;
> + u8 alarmvals[3];
> + int flags, ret;
> +
> + if (client->irq <= 0)
> + return -EINVAL;
It'd be cleaner just to have a second set of rtc_class_ops that can be
switched between based on whether a valid interrupt is specified.
Josh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
