rtc: pm8xxx: add support for devicetree

Add support for describing the PM8921/PM8058 RTC in device tree.

Additionally:
   - drop support for describing the RTC using platform data,
     as there are no current in tree users who do so.
   - make allow_set_time a device-specific flag, instead of mucking
     with the rtc_ops

Signed-off-by: Josh Cartwright <joshc@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 29 insertions, 23 deletions

diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c
index 91ac2e346aea..6e3cd345379d 100644
--- a/drivers/rtc/rtc-pm8xxx.c
+++ b/drivers/rtc/rtc-pm8xxx.c
@@ -9,7 +9,7 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */
-
+#include <linux/of.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/rtc.h>
@@ -19,9 +19,6 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
-#include <linux/mfd/pm8xxx/rtc.h>
-
-
 /* RTC Register offsets from RTC CTRL REG */
 #define PM8XXX_ALARM_CTRL_OFFSET        0x01
 #define PM8XXX_RTC_WRITE_OFFSET         0x02
@@ -39,6 +36,7 @@
  * struct pm8xxx_rtc -  rtc driver internal structure
  * @rtc:                rtc device for this driver.
  * @regmap:             regmap used to access RTC registers
+ * @allow_set_time:     indicates whether writing to the RTC is allowed
  * @rtc_alarm_irq:      rtc alarm irq number.
  * @rtc_base:           address of rtc control register.
  * @rtc_read_base:      base address of read registers.
@@ -51,6 +49,7 @@
 struct pm8xxx_rtc {
         struct rtc_device *rtc;
         struct regmap *regmap;
+        bool allow_set_time;
         int rtc_alarm_irq;
         int rtc_base;
         int rtc_read_base;
@@ -75,6 +74,9 @@ static int pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
         u8 value[NUM_8_BIT_RTC_REGS], alarm_enabled = 0, ctrl_reg;
         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 
+        if (!rtc_dd->allow_set_time)
+                return -EACCES;
+
         rtc_tm_to_time(tm, &secs);
 
         for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) {
@@ -298,8 +300,9 @@ rtc_rw_fail:
         return rc;
 }
 
-static struct rtc_class_ops pm8xxx_rtc_ops = {
+static const struct rtc_class_ops pm8xxx_rtc_ops = {
         .read_time      = pm8xxx_rtc_read_time,
+        .set_time       = pm8xxx_rtc_set_time,
         .set_alarm      = pm8xxx_rtc_set_alarm,
         .read_alarm     = pm8xxx_rtc_read_alarm,
         .alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable,
@@ -353,18 +356,26 @@ rtc_alarm_handled:
         return IRQ_HANDLED;
 }
 
+/*
+ * Hardcoded RTC bases until IORESOURCE_REG mapping is figured out
+ */
+static const struct of_device_id pm8xxx_id_table[] = {
+        { .compatible = "qcom,pm8921-rtc", .data = (void *) 0x11D },
+        { .compatible = "qcom,pm8058-rtc", .data = (void *) 0x1E8 },
+        { },
+};
+MODULE_DEVICE_TABLE(of, pm8xxx_id_table);
+
 static int pm8xxx_rtc_probe(struct platform_device *pdev)
 {
         int rc;
         unsigned int ctrl_reg;
-        bool rtc_write_enable = false;
         struct pm8xxx_rtc *rtc_dd;
-        struct resource *rtc_resource;
-        const struct pm8xxx_rtc_platform_data *pdata =
-                                                dev_get_platdata(&pdev->dev);
+        const struct of_device_id *match;
 
-        if (pdata != NULL)
-                rtc_write_enable = pdata->rtc_write_enable;
+        match = of_match_node(pm8xxx_id_table, pdev->dev.of_node);
+        if (!match)
+                return -ENXIO;
 
         rtc_dd = devm_kzalloc(&pdev->dev, sizeof(*rtc_dd), GFP_KERNEL);
         if (rtc_dd == NULL)
@@ -385,14 +396,10 @@ static int pm8xxx_rtc_probe(struct platform_device *pdev)
                 return -ENXIO;
         }
 
-        rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO,
-                                                    "pmic_rtc_base");
-        if (!(rtc_resource && rtc_resource->start)) {
-                dev_err(&pdev->dev, "RTC IO resource absent!\n");
-                return -ENXIO;
-        }
+        rtc_dd->allow_set_time = of_property_read_bool(pdev->dev.of_node,
+                                                      "allow-set-time");
 
-        rtc_dd->rtc_base = rtc_resource->start;
+        rtc_dd->rtc_base = (long) match->data;
 
         /* Setup RTC register addresses */
         rtc_dd->rtc_write_base = rtc_dd->rtc_base + PM8XXX_RTC_WRITE_OFFSET;
@@ -419,8 +426,6 @@ static int pm8xxx_rtc_probe(struct platform_device *pdev)
         }
 
         rtc_dd->ctrl_reg = ctrl_reg;
-        if (rtc_write_enable)
-                pm8xxx_rtc_ops.set_time = pm8xxx_rtc_set_time;
 
         platform_set_drvdata(pdev, rtc_dd);
 
@@ -479,9 +484,10 @@ static SIMPLE_DEV_PM_OPS(pm8xxx_rtc_pm_ops,
 static struct platform_driver pm8xxx_rtc_driver = {
         .probe          = pm8xxx_rtc_probe,
         .driver = {
-                .name   = PM8XXX_RTC_DEV_NAME,
-                .owner  = THIS_MODULE,
-                .pm     = &pm8xxx_rtc_pm_ops,
+                .name           = "rtc-pm8xxx",
+                .owner          = THIS_MODULE,
+                .pm             = &pm8xxx_rtc_pm_ops,
+                .of_match_table = pm8xxx_id_table,
         },
 };