Re: [PATCH] i2c: new driver for ds1337 RTC

Ladislav Michl
2005-04-07T11:27:35Z

On Thu, Apr 07, 2005 at 11:59:05AM +0200, Jean Delvare wrote:
> Please slice this into separarte patches. Adding support for the DS1339
> is one thing, bug fixes are another. I can't review patches which do
> that many different things at once.

I have objection ;-) Nothing in kernel seems to use that driver and
driver wasn't reviewed well enough before including. Therefore I'm still
considering it as a new driver which can be easily reviewed as whole.

> As a side note, please avoid noise in your patch. Converting constants
> from decimal to hexadecimal or renaming variables makes my review job
> way harder, as it distracts me from the real point of your patch.

Hexadecimal constant are there to match datasheet, local variables
should be short and with new_client is was reaching 80 column limit,
that's coding style and that's why I made that change.

Please consider that I would suggest these changes to driver author
before his patch went in tree in case I would read all that mailing
lists around. I'm lazy, my bad... Driver's author should have probably
last word anyway.

> Once you realize that the time I need to review a patch increases in a
> quadratic way (if not worse) relatively to the length of the patch, I am
> sure you will see why it is important to send small patches doing just
> one thing without noise.

Ok, sending cleanup fixes only. Support for ds1339 will be in separate
patch. Sorry I won't do more, because my time is also limited.

Here is patch which does cleanup/fixes only. It is still hard to review,
but that's living. I won't split it to smaller parts just because I had
to touch each single line in get/set date functions. Sorry if it sounds
impolite, but now I can't spend more time on it. Perhaps later, if
anyone don't buy it as is meanwhile... Please let me know when/if you will
accept support for DS1339.

Best regards,
ladis

===== drivers/i2c/chips/ds1337.c 1.1 vs edited =====
--- 1.1/drivers/i2c/chips/ds1337.c 2005-03-31 22:58:08 +02:00
+++ edited/drivers/i2c/chips/ds1337.c 2005-04-07 13:02:18 +02:00
@@ -2,8 +2,9 @@
* linux/drivers/i2c/chips/ds1337.c
*
* Copyright (C) 2005 James Chapman <jchapman@katalix.com>
+ * Copyright (C) 2005 Ladislav Michl <ladis@linux-mips.org>
*
- * based on linux/drivers/acron/char/pcf8583.c
+ * based on linux/drivers/acorn/char/pcf8583.c
* Copyright (C) 2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
@@ -25,12 +26,13 @@
#include <linux/list.h>

/* Device registers */
-#define DS1337_REG_HOUR 2
-#define DS1337_REG_DAY 3
-#define DS1337_REG_DATE 4
-#define DS1337_REG_MONTH 5
-#define DS1337_REG_CONTROL 14
-#define DS1337_REG_STATUS 15
+#define DS1337_REG_HOUR 0x02
+#define DS1337_REG_DAY 0x03
+#define DS1337_REG_DATE 0x04
+#define DS1337_REG_MONTH 0x05
+#define DS1337_REG_CONTROL 0x0e
+#define DS1337_REG_STATUS 0x0f
+#define DS1339_REG_CHARGE 0x10

/* FIXME - how do we export these interface constants? */
#define DS1337_GET_DATE 0
@@ -93,116 +95,74 @@
/*
* Chip access functions
*/
-static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt)
+static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
- struct ds1337_data *data = i2c_get_clientdata(client);
- int result;
- u8 buf[7];
- u8 val;
- struct i2c_msg msg[2];
- u8 offs = 0;
-
- if (!dt) {
- dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n",
- __FUNCTION__);
-
- return -EINVAL;
- }
-
- msg[0].addr = client->addr;
- msg[0].flags = 0;
- msg[0].len = 1;
- msg[0].buf = &offs;
-
- msg[1].addr = client->addr;
- msg[1].flags = I2C_M_RD;
- msg[1].len = sizeof(buf);
- msg[1].buf = &buf[0];
-
- result = client->adapter->algo->master_xfer(client->adapter,
- &msg[0], 2);
+ unsigned char buf[7] = { 0, }, addr[1] = { 0 };
+ struct i2c_msg msgs[2] = {
+ { client->addr, 0, 1, addr },
+ { client->addr, I2C_M_RD, 7, buf }
+ };
+ int result = i2c_transfer(client->adapter, msgs, 2);

- dev_dbg(&client->adapter->dev,
+ dev_dbg(&client->dev,
"%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
__FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6]);

- if (result >= 0) {
- dt->tm_sec = BCD_TO_BIN(buf[0]);
- dt->tm_min = BCD_TO_BIN(buf[1]);
- val = buf[2] & 0x3f;
- dt->tm_hour = BCD_TO_BIN(val);
- dt->tm_wday = BCD_TO_BIN(buf[3]) - 1;
- dt->tm_mday = BCD_TO_BIN(buf[4]);
- val = buf[5] & 0x7f;
- dt->tm_mon = BCD_TO_BIN(val);
- dt->tm_year = 1900 + BCD_TO_BIN(buf[6]);
+ if (result < 0) {
+ dev_err(&client->dev, "error reading data! %d\n", result);
+ result = -EIO;
+ } else {
+ tm->tm_sec = BCD2BIN(buf[0]);
+ tm->tm_min = BCD2BIN(buf[1]);
+ tm->tm_hour = BCD2BIN(buf[2] & 0x3f);
+ tm->tm_wday = BCD2BIN(buf[3]);
+ tm->tm_mday = BCD2BIN(buf[4]);
+ tm->tm_mon = BCD2BIN(buf[5] & 0x7f) - 1;
+ tm->tm_year = BCD2BIN(buf[6]);
if (buf[5] & 0x80)
- dt->tm_year += 100;
+ tm->tm_year += 100;

- dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, "
- "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
- __FUNCTION__, dt->tm_sec, dt->tm_min,
- dt->tm_hour, dt->tm_mday,
- dt->tm_mon, dt->tm_year, dt->tm_wday);
- } else {
- dev_err(&client->adapter->dev, "ds1337[%d]: error reading "
- "data! %d\n", data->id, result);
- result = -EIO;
+ dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
+ "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
+ tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ result = 0;
}

return result;
}

-static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
+static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
- struct ds1337_data *data = i2c_get_clientdata(client);
+ unsigned char buf[8];
int result;
- u8 buf[8];
- u8 val;
- struct i2c_msg msg[1];
-
- if (!dt) {
- dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n",
- __FUNCTION__);

- return -EINVAL;
- }
-
- dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, hours=%d, "
+ dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
- dt->tm_sec, dt->tm_min, dt->tm_hour,
- dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
+ tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

buf[0] = 0; /* reg offset */
- buf[1] = BIN_TO_BCD(dt->tm_sec);
- buf[2] = BIN_TO_BCD(dt->tm_min);
- buf[3] = BIN_TO_BCD(dt->tm_hour) | (1 << 6);
- buf[4] = BIN_TO_BCD(dt->tm_wday) + 1;
- buf[5] = BIN_TO_BCD(dt->tm_mday);
- buf[6] = BIN_TO_BCD(dt->tm_mon);
- if (dt->tm_year >= 2000) {
- val = dt->tm_year - 2000;
+ buf[1] = BIN2BCD(tm->tm_sec);
+ buf[2] = BIN2BCD(tm->tm_min);
+ buf[3] = BIN2BCD(tm->tm_hour) | (1 << 6);
+ buf[4] = BIN2BCD(tm->tm_wday);
+ buf[5] = BIN2BCD(tm->tm_mday);
+ buf[6] = BIN2BCD(tm->tm_mon + 1);
+ if (tm->tm_year >= 100) {
+ tm->tm_year -= 100;
buf[6] |= (1 << 7);
- } else {
- val = dt->tm_year - 1900;
}
- buf[7] = BIN_TO_BCD(val);
+ buf[7] = BIN2BCD(tm->tm_year);

- msg[0].addr = client->addr;
- msg[0].flags = 0;
- msg[0].len = sizeof(buf);
- msg[0].buf = &buf[0];
-
- result = client->adapter->algo->master_xfer(client->adapter,
- &msg[0], 1);
+ result = i2c_master_send(client, (char *)buf, sizeof(buf));
if (result < 0) {
- dev_err(&client->adapter->dev, "ds1337[%d]: error "
- "writing data! %d\n", data->id, result);
+ dev_err(&client->dev, "error writing data! %d\n", result);
result = -EIO;
- } else {
+ } else
result = 0;
- }

return result;
}
@@ -210,7 +170,7 @@
static int ds1337_command(struct i2c_client *client, unsigned int cmd,
void *arg)
{
- dev_dbg(&client->adapter->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
+ dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);

switch (cmd) {
case DS1337_GET_DATE:
@@ -254,10 +214,10 @@
*/
static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
{
- struct i2c_client *new_client;
+ struct i2c_client *client;
struct ds1337_data *data;
+ char *name;
int err = 0;
- const char *name = "";

if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_I2C))
@@ -273,12 +233,12 @@
/* The common I2C client data is placed right before the
* DS1337-specific data.
*/
- new_client = &data->client;
- i2c_set_clientdata(new_client, data);
- new_client->addr = address;
- new_client->adapter = adapter;
- new_client->driver = &ds1337_driver;
- new_client->flags = 0;
+ client = &data->client;
+ i2c_set_clientdata(client, data);
+ client->addr = address;
+ client->adapter = adapter;
+ client->driver = &ds1337_driver;
+ client->flags = 0;

/*
* Now we do the remaining detection. A negative kind means that
@@ -303,47 +263,52 @@
u8 data;

/* Check that status register bits 6-2 are zero */
- if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
+ if ((ds1337_read(client, DS1337_REG_STATUS, &data) < 0) ||
(data & 0x7c))
goto exit_free;

/* Check for a valid day register value */
- if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
+ if ((ds1337_read(client, DS1337_REG_DAY, &data) < 0) ||
(data == 0) || (data & 0xf8))
goto exit_free;

/* Check for a valid date register value */
- if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
+ if ((ds1337_read(client, DS1337_REG_DATE, &data) < 0) ||
(data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
(data >= 0x32))
goto exit_free;

/* Check for a valid month register value */
- if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
+ if ((ds1337_read(client, DS1337_REG_MONTH, &data) < 0) ||
(data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
((data >= 0x13) && (data <= 0x19)))
goto exit_free;

/* Check that control register bits 6-5 are zero */
- if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
+ if ((ds1337_read(client, DS1337_REG_CONTROL, &data) < 0) ||
(data & 0x60))
goto exit_free;

kind = ds1337;
}

- if (kind == ds1337)
+ switch (kind) {
+ case ds1337:
name = "ds1337";
+ break;
+ default:
+ name = "";
+ }

/* We can fill in the remaining client fields */
- strlcpy(new_client->name, name, I2C_NAME_SIZE);
+ strlcpy(client->name, name, I2C_NAME_SIZE);

/* Tell the I2C layer a new client has arrived */
- if ((err = i2c_attach_client(new_client)))
+ if ((err = i2c_attach_client(client)))
goto exit_free;

/* Initialize the DS1337 chip */
- ds1337_init_client(new_client);
+ ds1337_init_client(client);

/* Add client to local list */
data->id = ds1337_id++;