On 09/05/2018 21:33:55+0200, Giulio Benetti wrote:
> On m41txx you can enable open-drain OUT pin to check if offset is ok.
> Enabling OUT pin with freq_test attribute, OUT pin will tick 512 times
> faster than 1s tick base.
>
> Enable or Disable FT bit on CONTROL register if freq_test is 1 or 0.
>
> Signed-off-by: Giulio Benetti <giulio.benetti@xxxxxxxxxxxxxxxx>
> ---
> V2 => V3: export freq_test on sysfs only if supported(m41txx series)
>
> drivers/rtc/rtc-ds1307.c | 107 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 107 insertions(+)
>
> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index 33895668b363..79206bf21018 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -1042,6 +1042,109 @@ static int m41txx_rtc_set_offset(struct device *dev, long offset)
> return regmap_write(ds1307->regmap, M41TXX_REG_CONTROL, ctrl_reg);
> }
>
> +static ssize_t freq_test_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct ds1307 *ds1307 = dev_get_drvdata(dev);
> + unsigned long freq_test = 0;
> + unsigned int ctrl_reg;
> + int retval;
> +
> + retval = kstrtoul(buf, 10, &freq_test);
> + if ((retval < 0) || (retval > 1)) {
> + dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
> + return -EINVAL;
> + }
> +
> + regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
> +
> + if (freq_test)
> + ctrl_reg |= M41TXX_BIT_FT;
> + else
> + ctrl_reg &= ~M41TXX_BIT_FT;
> +
> + retval = regmap_write(ds1307->regmap, M41TXX_REG_CONTROL, ctrl_reg);
> +
Pleas use regmap_update_bits
> + return retval ? retval : count;
> +}
> +
> +static ssize_t freq_test_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct ds1307 *ds1307 = dev_get_drvdata(dev);
> + int freq_test = 0;
> + unsigned int ctrl_reg;
> +
> + regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
> +
> + if (ctrl_reg & M41TXX_BIT_FT)
> + freq_test = true;
> + else
> + freq_test = false;
> +
> + if ((freq_test < 0) || (freq_test > 1)) {
This will never happen
> + dev_err(dev, "Failed to read RTC Frequency Test\n");
> + sprintf(buf, "0\n");
> + return freq_test;
> + }
> +
> + return sprintf(buf, "%d\n", freq_test);
> +}
> +
> +static DEVICE_ATTR_RW(freq_test);
I'd prefer the file to be named frequency_test_enable
> +
> +static struct attribute *rtc_freq_test_attrs[] = {
> + &dev_attr_freq_test.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group rtc_freq_test_attr_group = {
> + .attrs = rtc_freq_test_attrs,
> +};
> +
> +static void rtc_calib_remove_sysfs_group(void *_dev)
> +{
> + struct device *dev = _dev;
> +
> + sysfs_remove_group(&dev->kobj, &rtc_freq_test_attr_group);
> +}
> +
> +static int ds1307_add_frequency_test(struct ds1307 *ds1307)
> +{
> + int err = 0;
> +
> + switch (ds1307->type) {
> + case m41t0:
> + case m41t00:
> + case m41t11:
> + /* Export sysfs entries */
> + err = sysfs_create_group(&(ds1307->dev)->kobj,
> + &rtc_freq_test_attr_group);
> + if (err) {
> + dev_err(ds1307->dev,
> + "Failed to create sysfs group: %d\n",
> + err);
> + return err;
> + }
> +
> + err = devm_add_action_or_reset(ds1307->dev,
> + rtc_calib_remove_sysfs_group,
> + ds1307->dev);
> + if (err) {
> + dev_err(ds1307->dev,
> + "Failed to add sysfs cleanup action: %d\n",
> + err);
You need to sysfs_remove_group here
> + return err;
> + }
> + break;
> + default:
> + break;
> + }
> +
> + return err;
> +}
> +
> /*----------------------------------------------------------------------*/
>
> static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
> @@ -1783,6 +1886,10 @@ static int ds1307_probe(struct i2c_client *client,
> if (err)
> return err;
>
> + err = ds1307_add_frequency_test(ds1307);
> + if (err)
> + return err;
> +
> if (chip->nvram_size) {
> struct nvmem_config nvmem_cfg = {
> .name = "ds1307_nvram",
> --
> 2.17.0
>
--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
