Hi,
On 07/12/2015 at 14:49:33 +0100, Juergen Borleis wrote :
> Use the function to read the whole time/date register in one turn and now
> check if the RTC signals an invalid time/date (due to a battery power loss
> for example). In this case ignore the time/date until it is really set
> again.
>
> Signed-off-by: Juergen Borleis <j...@pengutronix.de>
> ---
> drivers/rtc/rtc-pcf85063.c | 45 +++++++++++++++++++--------------------------
> 1 file changed, 19 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
> index 75f2866..abed934 100644
> --- a/drivers/rtc/rtc-pcf85063.c
> +++ b/drivers/rtc/rtc-pcf85063.c
> @@ -22,6 +22,7 @@
> #define PCF85063_REG_CTRL2 0x01
>
> #define PCF85063_REG_SC 0x04 /* datetime */
> +#define PCF85063_REG_SC_OS 0x80
> #define PCF85063_REG_MN 0x05
> #define PCF85063_REG_HR 0x06
> #define PCF85063_REG_DM 0x07
> @@ -77,39 +78,31 @@ static int pcf85063_read_time(struct i2c_client *client,
> u8 *buf, u16 size)
> */
> static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time
> *tm)
> {
> + int rc;
> struct pcf85063 *pcf85063 = i2c_get_clientdata(client);
> - unsigned char buf[13] = { PCF85063_REG_CTRL1 };
> - struct i2c_msg msgs[] = {
> - {/* setup read ptr */
> - .addr = client->addr,
> - .len = 1,
> - .buf = buf
> - },
> - {/* read status + date */
> - .addr = client->addr,
> - .flags = I2C_M_RD,
> - .len = 13,
> - .buf = buf
> - },
> - };
> + u8 regs[7];
>
> - /* read registers */
> - if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
> - dev_err(&client->dev, "%s: read error\n", __func__);
> - return -EIO;
Isn't that already reading the time and date register in one block? I'd
say you are simply reading less registers. Also, maybe you could use
i2c_smbus_read_block_data?
> + rc = pcf85063_read_time(client, regs, sizeof(regs));
> + if (rc < 0)
> + return rc;
> +
> + /* if the clock has lost its power it makes no sense to use its time */
> + if (regs[0] & PCF85063_REG_SC_OS) {
> + dev_warn(&client->dev, "Power loss detected, invalid time\n");
> + return -EINVAL;
> }
That part is more useful and as I understand it is what you are trying
to fix.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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