Thread (22 messages) 22 messages, 5 authors, 2014-09-09

Re: [PATCH] rtc: ds1307: add trickle charger device tree binding

From: Mark Rutland <hidden>
Date: 2014-08-28 13:00:26
Also in: lkml

On Thu, Aug 28, 2014 at 01:42:44PM +0100, Matti Vaittinen wrote:
quoted hunk ↗ jump to hunk
Patch adding support for specifying trickle charger setup from device
tree. Patch is based on linux-next tree.


Some DS13XX devices have "trickle chargers". Introduce a device tree binding
for specifying the setup and register values.

Signed-off-by: Matti Vaittinen <redacted>
---
 .../devicetree/bindings/i2c/trivial-devices.txt    |  1 -
 .../devicetree/bindings/rtc/dallas,ds1339.txt      | 19 ++++++++++
 drivers/rtc/rtc-ds1307.c                           | 44 ++++++++++++++++++++--
 3 files changed, 59 insertions(+), 5 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/rtc/dallas,ds1339.txt
diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
index 6af570e..e9206a4 100644
--- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
+++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
@@ -35,7 +35,6 @@ catalyst,24c32		i2c serial eeprom
 cirrus,cs42l51		Cirrus Logic CS42L51 audio codec
 dallas,ds1307		64 x 8, Serial, I2C Real-Time Clock
 dallas,ds1338		I2C RTC with 56-Byte NV RAM
-dallas,ds1339		I2C Serial Real-Time Clock
 dallas,ds1340		I2C RTC with Trickle Charger
 dallas,ds1374		I2C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output
 dallas,ds1631		High-Precision Digital Thermometer
diff --git a/Documentation/devicetree/bindings/rtc/dallas,ds1339.txt b/Documentation/devicetree/bindings/rtc/dallas,ds1339.txt
new file mode 100644
index 0000000..9faf40e
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/dallas,ds1339.txt
@@ -0,0 +1,19 @@
+* Dallas DS1339		I2C Serial Real-Time Clock
+
+Required properties:
+- compatible: Should contain "dallas,ds1339".
+- reg: I2C address for chip
+
+Optional properties:
+- trickle_setup : Used Trickle Charger configuration,
+        corresponding to 5 lowest bits in trickle charger register.
s/_/-/ in property names please.

What do these bits do? is there any documentation available?

Why do they need to be in the DT?

Why do we not have a higher-level description?
+- trickle_reg   : Trickle charger register address. Defaults to 0x10 for ds1339.
Is this expected to change? Why does this need to be in the DT?
quoted hunk ↗ jump to hunk
+
+Example:
+	ds1339: rtc@68 {
+		compatible = "dallas,ds1339";
+        trickle_setup= <0x5>;
+		reg = <0x68>;
+	};
+
+
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index f03d5ba..f9b1244 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -126,9 +126,10 @@ struct chip_desc {
 	u16			nvram_offset;
 	u16			nvram_size;
 	u16			trickle_charger_reg;
+	u8		  trickle_charger_setup;
 };
 
-static const struct chip_desc chips[last_ds_type] = {
+static struct chip_desc chips[last_ds_type] = {
 	[ds_1307] = {
 		.nvram_offset	= 8,
 		.nvram_size	= 56,
@@ -835,13 +836,37 @@ ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 
 /*----------------------------------------------------------------------*/
 
+static void trickle_charger_of_init(struct chip_desc *chip,
+			struct device_node *node)
+{
+	int plen = 0;
+	const uint32_t *setup;
+	const uint32_t *reg;
+
+	setup = of_get_property(node, "trickle_setup" , &plen);
+	if (plen != 4)
+		goto out;
+	chip->trickle_charger_setup = (u8)*setup;
This isn't endian-clean, and the casting is unnecessary.

Use the of_property_read_u32 accessor, with a u32 temporary variable.
+	plen = 0;
+	reg = of_get_property(node, "trickle_reg" , &plen);
+	if (plen == 4)
+		chip->trickle_charger_reg = (u16)*reg;
Likewise.

Mark.
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