Patchwork rtc: add initial support for mcp7941x parts

login
register
mail settings
Submitter David Anders
Date Sept. 23, 2011, 10:57 p.m.
Message ID <1316818643.55745.YahooMailNeo@web120018.mail.ne1.yahoo.com>
Download mbox | patch
Permalink /patch/116194/
State New
Headers show

Comments

David Anders - Sept. 23, 2011, 10:57 p.m.
From 691dc915a8de8cb52c5d3e5a4e27c724d393f2d4 Mon Sep 17 00:00:00 2001
From: David Anders <danders@tincantools.com>
Date: Fri, 23 Sep 2011 17:32:47 -0500
Subject: [PATCH] rtc: add initial support for mcp7941x parts

this patch adds initial support for the microchip mcp7941x series
of real time clocks. the mcp7941x series is generally compatible
with the ds1307 and ds1337 rtc devices from dallas semiconductor.
minor differences include a backup battery enable bit, and the
polarity of the oscillator enable bit.

Signed-off-by: David Anders <danders@tincantools.com>
---
 drivers/rtc/rtc-ds1307.c |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)

Patch

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index b2005b4..52a8c8c 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -35,6 +35,7 @@  enum ds_type {
     ds_3231,
     m41t00,
     rx_8025,
+    mcp7941x,
     // rs5c372 too?  different address...
 };
 
@@ -42,6 +43,7 @@  enum ds_type {
 /* RTC registers don't differ much, except for the century flag */
 #define DS1307_REG_SECS        0x00    /* 00-59 */
 #    define DS1307_BIT_CH        0x80
+#    define MCP7941X_BIT_ST        0x80
 #    define DS1340_BIT_nEOSC        0x80
 #define DS1307_REG_MIN        0x01    /* 00-59 */
 #define DS1307_REG_HOUR        0x02    /* 00-23, or 1-12{am,pm} */
@@ -50,6 +52,7 @@  enum ds_type {
 #    define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
 #    define DS1340_BIT_CENTURY    0x40    /* in REG_HOUR */
 #define DS1307_REG_WDAY        0x03    /* 01-07 */
+#    define MCP7941X_BIT_VBATEN    0x08
 #define DS1307_REG_MDAY        0x04    /* 01-31 */
 #define DS1307_REG_MONTH    0x05    /* 01-12 */
 #    define DS1337_BIT_CENTURY    0x80    /* in REG_MONTH */
@@ -138,6 +141,8 @@  static const struct chip_desc chips[] = {
 [m41t00] = {
 },
 [rx_8025] = {
+},
+[mcp7941x] = {
 }, };
 
 static const struct i2c_device_id ds1307_id[] = {
@@ -151,6 +156,7 @@  static const struct i2c_device_id ds1307_id[] = {
     { "m41t00", m41t00 },
     { "pt7c4338", ds_1307 },
     { "rx8025", rx_8025 },
+    { "mcp7941x", mcp7941x },
     { }
 };
 MODULE_DEVICE_TABLE(i2c, ds1307_id);
@@ -365,6 +371,10 @@  static int ds1307_set_time(struct device *dev, struct rtc_time *t)
         buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
                 | DS1340_BIT_CENTURY;
         break;
+    case mcp7941x:
+        buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
+        buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
+        break;
     default:
         break;
     }
@@ -809,6 +819,23 @@  read_rtc:
             dev_warn(&client->dev, "SET TIME!\n");
         }
         break;
+    case mcp7941x:
+        /* make sure that the backup battery is enabled */
+        if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
+            i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
+                    ds1307->regs[DS1307_REG_WDAY]
+                    | MCP7941X_BIT_VBATEN);
+        }
+
+        /* clock halted?  turn it on, so clock can tick. */
+        if (!(tmp & MCP7941X_BIT_ST)) {
+            i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
+                    MCP7941X_BIT_ST);
+            dev_warn(&client->dev, "SET TIME!\n");
+            goto read_rtc;
+        }
+
+        break;
     case rx_8025:
     case ds_1337:
     case ds_1339: