diff mbox

[v2] input: touchscreen: add OF match table for ads7846

Message ID 1308015955-8286-1-git-send-email-Baohua.Song@csr.com (mailing list archive)
State New, archived
Headers show

Commit Message

Barry Song June 14, 2011, 1:45 a.m. UTC
The current ads7846 has no OF match table. The method used is by applying a heuristic (of_modalias_node) which tries to name the device in a way that will match an existing device driver.
This patch adds explicit OF match table for ads7846, then the normal device tree match behaviour will always work.
It has been tested on PRIMA2 EVB board of CSR with a SPI's child node like the below:
ts@0 {
        compatible = "ti,ads7845";
        reg = <0x0>;
        spi-max-frequency = <31250>;
        interrupts = <90>;
};

Signed-off-by: Barry Song <Baohua.Song@csr.com>
Cc: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
---
 .../devicetree/bindings/input/ads7846.txt          |   20 ++++++++++++++++++++
 drivers/input/touchscreen/ads7846.c                |   14 ++++++++++++++
 2 files changed, 34 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/input/ads7846.txt

Comments

Thomas Chou June 14, 2011, 6:15 a.m. UTC | #1
On 06/14/2011 09:45 AM, Barry Song wrote:
> The current ads7846 has no OF match table. The method used is by applying a heuristic (of_modalias_node) which tries to name the device in a way that will match an existing device driver.
> This patch adds explicit OF match table for ads7846, then the normal device tree match behaviour will always work.
> It has been tested on PRIMA2 EVB board of CSR with a SPI's child node like the below:
> ts@0 {
>          compatible = "ti,ads7845";
>          reg =<0x0>;
>          spi-max-frequency =<31250>;
>          interrupts =<90>;
> };
>

Hi Barry,

Thank you very much for your help. Could we add an option for gpio 
pendown, like this?

- gpios : should specify GPIO used for pendown.

If interrupt node is not present in this node, gpio_to_irq of the pen
down GPIO will be used.

Best regards,
Thomas
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Thomas Chou June 15, 2011, 4:01 a.m. UTC | #2
On 06/14/2011 02:38 PM, Baohua Song wrote:
>> Could we add an option for gpio
>> pendown, like this?
>>
>> - gpios : should specify GPIO used for pendown.
>>
>> If interrupt node is not present in this node, gpio_to_irq of the pen
>> down GPIO will be used.
> 
> I disagree... An optional gpio node doesn't make sense here. The result of gpio_to_irq is still an interrupt, then we can place the result in interrupt node.
> And the ads7846 driver required an interrupt node but not a gpio node since we don't find any of_get_gpio() in this driver.
> BTW, it even doesn’t make sense to call function gpio_to_irq in a driver like ads7846. on the contrary, drivers/input/keyboard/gpio_keys.c is really an good user of gpio_to_irq.

Hi Barry,

The classical platform data is seldom used when device tree is passed.
So it would be better to disable platform data passing to verify device
tree support.

Without platform data passing, we don't have pdata and
pdata->get_pendown_state func for ads7846_setup_pendown(). The
ads7846_probe() will need updates on this.

Passing gpio for pendown might be a possible solution, as device tree
supports "gpios" node. We could use of_get_gpio_flags() to retrieve it.

I sent an earlier work of mine on this back in Feb. to you.

Best regards,
Thomas

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diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/input/ads7846.txt b/Documentation/devicetree/bindings/input/ads7846.txt
new file mode 100644
index 0000000..36c1fd0
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/ads7846.txt
@@ -0,0 +1,20 @@ 
+ADS7846/ADS7845/ADS7843 touchscreen connected to a SPI bus
+
+Required properties:
+- compatible : should be "ti,ads7846", "ti,ads7845" or "ti,ads7843"
+- reg : should specify SPI address (chip-select number).
+- spi-max-frequency : maximum frequency for this device (Hz).
+- interrupts : the interrupt of pendown.
+
+Optional properties:
+- interrupt-parent : the phandle for the interrupt controller that
+  services interrupts for this device.
+
+Example:
+
+	ts@0 {
+		compatible = "ti,ads7845",
+		reg = <0>;
+		spi-max-frequency = <31250>;
+		interrupts = <90>;
+	};
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 5196861..fa9345c 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -28,6 +28,7 @@ 
 #include <linux/slab.h>
 #include <linux/pm.h>
 #include <linux/gpio.h>
+#include <linux/of.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/ads7846.h>
 #include <linux/regulator/consumer.h>
@@ -1425,12 +1426,25 @@  static int __devexit ads7846_remove(struct spi_device *spi)
 	return 0;
 }
 
+#if defined(CONFIG_OF)
+static struct of_device_id ads7846_spi_of_match_table[] __devinitdata = {
+	{ .compatible = "ti,ads7846", },
+	{ .compatible = "ti,ads7845", },
+	{ .compatible = "ti,ads7843", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ads7846_spi_of_match_table);
+#else
+#define ads7846_spi_of_match_table NULL
+#endif
+
 static struct spi_driver ads7846_driver = {
 	.driver = {
 		.name	= "ads7846",
 		.bus	= &spi_bus_type,
 		.owner	= THIS_MODULE,
 		.pm	= &ads7846_pm,
+		.of_match_table = ads7846_spi_of_match_table,
 	},
 	.probe		= ads7846_probe,
 	.remove		= __devexit_p(ads7846_remove),