target/linux/brcm2708/patches-4.4/0137-rtc-ds1307-add-support-for-the-DT-property-wakeup-so.patch

   1 From e4bd962eeb728b924ebdaca077c2136280a190f2 Mon Sep 17 00:00:00 2001
   2 From: Michael Lange <linuxstuff@milaw.biz>
   3 Date: Thu, 21 Jan 2016 18:10:16 +0100
   4 Subject: [PATCH] rtc: ds1307: add support for the DT property 'wakeup-source'
   5
   6 For RTC chips with no IRQ directly connected to the SoC, the RTC chip
   7 can be forced as a wakeup source by stating that explicitly in
   8 the device's .dts file using the "wakeup-source" boolean property.
   9 This will guarantee the 'wakealarm' sysfs entry is available on the
  10 device, if supported by the RTC.
  11
  12 With these changes to the driver rtc-ds1307 and the necessary entries
  13 in the .dts file, I get an working ds1337 RTC on the Witty Pi extension
  14 board by UUGear for the Raspberry Pi.
  15
  16 An example for the entry in the .dts file:
  17
  18         rtc: ds1337@68 {
  19                 compatible = "dallas,ds1337";
  20                 reg = <0x68>;
  21                 wakeup-source;
  22
  23 If the "wakeup-source" property is set, do not request an IRQ.
  24 Set also UIE mode to unsupported, to get a working 'hwclock' binary.
  25
  26 Signed-off-by: Michael Lange <linuxstuff@milaw.biz>
  27 Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
  28 ---
  29  drivers/rtc/rtc-ds1307.c | 29 +++++++++++++++++++++++++++--
  30  1 file changed, 27 insertions(+), 2 deletions(-)
  31
  32 --- a/drivers/rtc/rtc-ds1307.c
  33 +++ b/drivers/rtc/rtc-ds1307.c
  34 @@ -860,6 +860,7 @@ static int ds1307_probe(struct i2c_clien
  35         struct chip_desc        *chip = &chips[id->driver_data];
  36         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
  37         bool                    want_irq = false;
  38 +       bool                    ds1307_can_wakeup_device = false;
  39         unsigned char           *buf;
  40         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
  41         irq_handler_t   irq_handler = ds1307_irq;
  42 @@ -907,6 +908,20 @@ static int ds1307_probe(struct i2c_clien
  43                 ds1307->write_block_data = ds1307_write_block_data;
  44         }
  45
  46 +#ifdef CONFIG_OF
  47 +/*
  48 + * For devices with no IRQ directly connected to the SoC, the RTC chip
  49 + * can be forced as a wakeup source by stating that explicitly in
  50 + * the device's .dts file using the "wakeup-source" boolean property.
  51 + * If the "wakeup-source" property is set, don't request an IRQ.
  52 + * This will guarantee the 'wakealarm' sysfs entry is available on the device,
  53 + * if supported by the RTC.
  54 + */
  55 +       if (of_property_read_bool(client->dev.of_node, "wakeup-source")) {
  56 +               ds1307_can_wakeup_device = true;
  57 +       }
  58 +#endif
  59 +
  60         switch (ds1307->type) {
  61         case ds_1337:
  62         case ds_1339:
  63 @@ -925,11 +940,13 @@ static int ds1307_probe(struct i2c_clien
  64                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
  65
  66                 /*
  67 -                * Using IRQ?  Disable the square wave and both alarms.
  68 +                * Using IRQ or defined as wakeup-source?
  69 +                * Disable the square wave and both alarms.
  70                  * For some variants, be sure alarms can trigger when we're
  71                  * running on Vbackup (BBSQI/BBSQW)
  72                  */
  73 -               if (ds1307->client->irq > 0 && chip->alarm) {
  74 +               if (chip->alarm && (ds1307->client->irq > 0 ||
  75 +                                               ds1307_can_wakeup_device)) {
  76                         ds1307->regs[0] |= DS1337_BIT_INTCN
  77                                         | bbsqi_bitpos[ds1307->type];
  78                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
  79 @@ -1144,6 +1161,14 @@ read_rtc:
  80                 return PTR_ERR(ds1307->rtc);
  81         }
  82
  83 +       if (ds1307_can_wakeup_device) {
  84 +               /* Disable request for an IRQ */
  85 +               want_irq = false;
  86 +               dev_info(&client->dev, "'wakeup-source' is set, request for an IRQ is disabled!\n");
  87 +               /* We cannot support UIE mode if we do not have an IRQ line */
  88 +               ds1307->rtc->uie_unsupported = 1;
  89 +       }
  90 +
  91         if (want_irq) {
  92                 err = devm_request_threaded_irq(&client->dev,
  93                                                 client->irq, NULL, irq_handler,