linux-kernel - Re: [PATCHv5 0/8] 2c: Relax mandatory I2C ID table passing

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Date:	Fri, 10 Jun 2016 15:32:00 +0200
From:	Wolfram Sang <wsa@...-dreams.de>
To:	Kieran Bingham <kieran@...uared.org.uk>
Cc:	Javier Martinez Canillas <javier@....samsung.com>,
	Lee Jones <lee.jones@...aro.org>, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, grant.likely@...aro.org,
	sameo@...ux.intel.com
Subject: Re: [PATCHv5 0/8] 2c: Relax mandatory I2C ID table passing


> When I reported :
> 
> > * new_device (built-in, and external module)
> > echo ds1307 0x68 > /sys/bus/i2c/devices/i2c-2/new_device
> > cat /sys/class/rtc/rtc0/date
> > 
> > - Both of those worked fine.
> 
> That was *without* Javier's patch, but hopefully obviously *with* Lee's
> patchset.
> 
> Do you need this testing *with* Javiers patch as well?

Without Javiers patch. But with a modified rtc driver which will only
use proper compatibles, no i2c_device_ids, and probe_new. And this one
should be able to instantiate via userspace with the driver builtin.

We have documented ways of instantiating. All I ask for is to make sure
the old style and new style work with them. Check the attached sketch
for an example (only compile-tested and conversion to probe_new is
missing). Can you instantiate the "maxim,ds1307" (with the additional
printout) and "dallas,ds1307" via userspace?

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 821d9c089cdb48..10a4e5bc923e07 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -31,6 +31,7 @@
  */
 enum ds_type {
 	ds_1307,
+	maxim_1307,
 	ds_1337,
 	ds_1338,
 	ds_1339,
@@ -144,6 +145,10 @@ static struct chip_desc chips[last_ds_type] = {
 		.nvram_offset	= 8,
 		.nvram_size	= 56,
 	},
+	[maxim_1307] = {
+		.nvram_offset	= 8,
+		.nvram_size	= 56,
+	},
 	[ds_1337] = {
 		.alarm		= 1,
 	},
@@ -173,23 +178,6 @@ static struct chip_desc chips[last_ds_type] = {
 	},
 };
 
-static const struct i2c_device_id ds1307_id[] = {
-	{ "ds1307", ds_1307 },
-	{ "ds1337", ds_1337 },
-	{ "ds1338", ds_1338 },
-	{ "ds1339", ds_1339 },
-	{ "ds1388", ds_1388 },
-	{ "ds1340", ds_1340 },
-	{ "ds3231", ds_3231 },
-	{ "m41t00", m41t00 },
-	{ "mcp7940x", mcp794xx },
-	{ "mcp7941x", mcp794xx },
-	{ "pt7c4338", ds_1307 },
-	{ "rx8025", rx_8025 },
-	{ }
-};
-MODULE_DEVICE_TABLE(i2c, ds1307_id);
-
 /*----------------------------------------------------------------------*/
 
 #define BLOCK_DATA_MAX_TRIES 10
@@ -1435,6 +1423,9 @@ read_rtc:
 	 */
 	tmp = ds1307->regs[DS1307_REG_SECS];
 	switch (ds1307->type) {
+	case maxim_1307:
+		dev_info(&client->dev, "I'm a Maxim\n");
+		/* fallthrough */
 	case ds_1307:
 	case m41t00:
 		/* clock halted?  turn it on, so clock can tick. */
@@ -1610,13 +1601,22 @@ static int ds1307_remove(struct i2c_client *client)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id ds1307_dt_ids[] = {
+	{ .compatible = "dallas,ds1307", .data = (void *)ds_1307 },
+	{ .compatible = "maxim,ds1307", .data = (void *)maxim_1307 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ds1302_dt_ids);
+#endif
+
 static struct i2c_driver ds1307_driver = {
 	.driver = {
 		.name	= "rtc-ds1307",
+		.of_match_table = of_match_ptr(ds1307_dt_ids),
 	},
 	.probe		= ds1307_probe,
 	.remove		= ds1307_remove,
-	.id_table	= ds1307_id,
 };
 
 module_i2c_driver(ds1307_driver);



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