Input: rotary-encoder - add DT bindings

This adds devicetree bindings to the rotary encoder driver and some documentation about how to use them. Tested on a PXA3xx platform. Signed-off-by: Daniel Mack <zonque@gmail.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: rotary-encoder - add DT bindings
This adds devicetree bindings to the rotary encoder driver and some documentation about how to use them. Tested on a PXA3xx platform. Signed-off-by: Daniel Mack <zonque@gmail.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Daniel Mack · Dmitry Torokhov
1 parent ce91953782
Showing 2 changed files with 116 additions and 16 deletions Side-by-side Diff
Documentation/devicetree/bindings/input/rotary-encoder.txt
drivers/input/misc/rotary_encoder.c
+Rotary encoder DT bindings
+
+Required properties:
+- gpios: a spec for two GPIOs to be used
+
+Optional properties:
+- linux,axis: the input subsystem axis to map to this rotary encoder.
+  Defaults to 0 (ABS_X / REL_X)
+- rotary-encoder,steps: Number of steps in a full turnaround of the
+  encoder. Only relevant for absolute axis. Defaults to 24 which is a
+  typical value for such devices.
+- rotary-encoder,relative-axis: register a relative axis rather than an
+  absolute one. Relative axis will only generate +1/-1 events on the input
+  device, hence no steps need to be passed.
+- rotary-encoder,rollover: Automatic rollove when the rotary value becomes
+  greater than the specified steps or smaller than 0. For absolute axis only.
+- rotary-encoder,half-period: Makes the driver work on half-period mode.
+
+See Documentation/input/rotary-encoder.txt for more information.
+
+Example:
+
+		rotary@0 {
+			compatible = "rotary-encoder";
+			gpios = <&gpio 19 1>, <&gpio 20 0>; /* GPIO19 is inverted */
+			linux,axis = <0>; /* REL_X */
+			rotary-encoder,relative-axis;
+		};
+
+		rotary@1 {
+			compatible = "rotary-encoder";
+			gpios = <&gpio 21 0>, <&gpio 22 0>;
+			linux,axis = <1>; /* ABS_Y */
+			rotary-encoder,steps = <24>;
+			rotary-encoder,rollover;
+		};
@@ -24,6 +24,8 @@
 #include <linux/gpio.h>
 #include <linux/rotary_encoder.h>
 #include <linux/slab.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
  
 #define DRV_NAME "rotary-encoder"
  
@@ -140,6 +142,56 @@
 	return IRQ_HANDLED;
 }
  
+#ifdef CONFIG_OF
+static struct of_device_id rotary_encoder_of_match[] = {
+	{ .compatible = "rotary-encoder", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);
+
+static struct rotary_encoder_platform_data * __devinit
+rotary_encoder_parse_dt(struct device *dev)
+{
+	const struct of_device_id *of_id =
+				of_match_device(rotary_encoder_of_match, dev);
+	struct device_node *np = dev->of_node;
+	struct rotary_encoder_platform_data *pdata;
+	enum of_gpio_flags flags;
+
+	if (!of_id || !np)
+		return NULL;
+
+	pdata = kzalloc(sizeof(struct rotary_encoder_platform_data),
+			GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps);
+	of_property_read_u32(np, "linux,axis", &pdata->axis);
+
+	pdata->gpio_a = of_get_gpio_flags(np, 0, &flags);
+	pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;
+
+	pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
+	pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
+
+	pdata->relative_axis = !!of_get_property(np,
+					"rotary-encoder,relative-axis", NULL);
+	pdata->rollover = !!of_get_property(np,
+					"rotary-encoder,rollover", NULL);
+	pdata->half_period = !!of_get_property(np,
+					"rotary-encoder,half-period", NULL);
+
+	return pdata;
+}
+#else
+static inline struct rotary_encoder_platform_data *
+rotary_encoder_parse_dt(struct device *dev)
+{
+	return NULL;
+}
+#endif
+
 static int __devinit rotary_encoder_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
  
@@ -150,14 +202,19 @@
 	int err;
  
 	if (!pdata) {
-		dev_err(&pdev->dev, "missing platform data\n");
-		return -ENOENT;
+		pdata = rotary_encoder_parse_dt(dev);
+		if (IS_ERR(pdata))
+			return PTR_ERR(pdata);
+
+		if (!pdata) {
+			dev_err(dev, "missing platform data\n");
+			return -EINVAL;
+		}
 	}
  
 	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
 	input = input_allocate_device();
 	if (!encoder || !input) {
-		dev_err(&pdev->dev, "failed to allocate memory for device\n");
 		err = -ENOMEM;
 		goto exit_free_mem;
 	}
  
@@ -165,10 +222,9 @@
 	encoder->input = input;
 	encoder->pdata = pdata;
  
-	/* create and register the input driver */
 	input->name = pdev->name;
 	input->id.bustype = BUS_HOST;
-	input->dev.parent = &pdev->dev;
+	input->dev.parent = dev;
  
 	if (pdata->relative_axis) {
 		input->evbit[0] = BIT_MASK(EV_REL);
  
@@ -179,17 +235,11 @@
 				     pdata->axis, 0, pdata->steps, 0, 1);
 	}
  
-	err = input_register_device(input);
-	if (err) {
-		dev_err(dev, "failed to register input device\n");
-		goto exit_free_mem;
-	}
-
 	/* request the GPIOs */
 	err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev));
 	if (err) {
 		dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a);
-		goto exit_unregister_input;
+		goto exit_free_mem;
 	}
  
 	err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev));
  
  
  
@@ -225,22 +275,30 @@
 		goto exit_free_irq_a;
 	}
  
+	err = input_register_device(input);
+	if (err) {
+		dev_err(dev, "failed to register input device\n");
+		goto exit_free_irq_b;
+	}
+
 	platform_set_drvdata(pdev, encoder);
  
 	return 0;
  
+exit_free_irq_b:
+	free_irq(encoder->irq_b, encoder);
 exit_free_irq_a:
 	free_irq(encoder->irq_a, encoder);
 exit_free_gpio_b:
 	gpio_free(pdata->gpio_b);
 exit_free_gpio_a:
 	gpio_free(pdata->gpio_a);
-exit_unregister_input:
-	input_unregister_device(input);
-	input = NULL; /* so we don't try to free it */
 exit_free_mem:
 	input_free_device(input);
 	kfree(encoder);
+	if (!dev_get_platdata(&pdev->dev))
+		kfree(pdata);
+
 	return err;
 }
  
  
  
@@ -253,10 +311,15 @@
 	free_irq(encoder->irq_b, encoder);
 	gpio_free(pdata->gpio_a);
 	gpio_free(pdata->gpio_b);
+
 	input_unregister_device(encoder->input);
-	platform_set_drvdata(pdev, NULL);
 	kfree(encoder);
  
+	if (!dev_get_platdata(&pdev->dev))
+		kfree(pdata);
+
+	platform_set_drvdata(pdev, NULL);
+
 	return 0;
 }
  
@@ -266,6 +329,7 @@
 	.driver		= {
 		.name	= DRV_NAME,
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(rotary_encoder_of_match),
 	}
 };
 module_platform_driver(rotary_encoder_driver);
	1	+Rotary encoder DT bindings
	2	+
	3	+Required properties:
	4	+- gpios: a spec for two GPIOs to be used
	5	+
	6	+Optional properties:
	7	+- linux,axis: the input subsystem axis to map to this rotary encoder.
	8	+ Defaults to 0 (ABS_X / REL_X)
	9	+- rotary-encoder,steps: Number of steps in a full turnaround of the
	10	+ encoder. Only relevant for absolute axis. Defaults to 24 which is a
	11	+ typical value for such devices.
	12	+- rotary-encoder,relative-axis: register a relative axis rather than an
	13	+ absolute one. Relative axis will only generate +1/-1 events on the input
	14	+ device, hence no steps need to be passed.
	15	+- rotary-encoder,rollover: Automatic rollove when the rotary value becomes
	16	+ greater than the specified steps or smaller than 0. For absolute axis only.
	17	+- rotary-encoder,half-period: Makes the driver work on half-period mode.
	18	+
	19	+See Documentation/input/rotary-encoder.txt for more information.
	20	+
	21	+Example:
	22	+
	23	+ rotary@0 {
	24	+ compatible = "rotary-encoder";
	25	+ gpios = <&gpio 19 1>, <&gpio 20 0>; /* GPIO19 is inverted */
	26	+ linux,axis = <0>; /* REL_X */
	27	+ rotary-encoder,relative-axis;
	28	+ };
	29	+
	30	+ rotary@1 {
	31	+ compatible = "rotary-encoder";
	32	+ gpios = <&gpio 21 0>, <&gpio 22 0>;
	33	+ linux,axis = <1>; /* ABS_Y */
	34	+ rotary-encoder,steps = <24>;
	35	+ rotary-encoder,rollover;
	36	+ };
...	...	@@ -24,6 +24,8 @@
24	24	#include <linux/gpio.h>
25	25	#include <linux/rotary_encoder.h>
26	26	#include <linux/slab.h>
	27	+#include <linux/of_platform.h>
	28	+#include <linux/of_gpio.h>
27	29
28	30	#define DRV_NAME "rotary-encoder"
29	31
...	...	@@ -140,6 +142,56 @@
140	142	return IRQ_HANDLED;
141	143	}
142	144
	145	+#ifdef CONFIG_OF
	146	+static struct of_device_id rotary_encoder_of_match[] = {
	147	+ { .compatible = "rotary-encoder", },
	148	+ { },
	149	+};
	150	+MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);
	151	+
	152	+static struct rotary_encoder_platform_data * __devinit
	153	+rotary_encoder_parse_dt(struct device *dev)
	154	+{
	155	+ const struct of_device_id *of_id =
	156	+ of_match_device(rotary_encoder_of_match, dev);
	157	+ struct device_node *np = dev->of_node;
	158	+ struct rotary_encoder_platform_data *pdata;
	159	+ enum of_gpio_flags flags;
	160	+
	161	+ if (!of_id \|\| !np)
	162	+ return NULL;
	163	+
	164	+ pdata = kzalloc(sizeof(struct rotary_encoder_platform_data),
	165	+ GFP_KERNEL);
	166	+ if (!pdata)
	167	+ return ERR_PTR(-ENOMEM);
	168	+
	169	+ of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps);
	170	+ of_property_read_u32(np, "linux,axis", &pdata->axis);
	171	+
	172	+ pdata->gpio_a = of_get_gpio_flags(np, 0, &flags);
	173	+ pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;
	174	+
	175	+ pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
	176	+ pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
	177	+
	178	+ pdata->relative_axis = !!of_get_property(np,
	179	+ "rotary-encoder,relative-axis", NULL);
	180	+ pdata->rollover = !!of_get_property(np,
	181	+ "rotary-encoder,rollover", NULL);
	182	+ pdata->half_period = !!of_get_property(np,
	183	+ "rotary-encoder,half-period", NULL);
	184	+
	185	+ return pdata;
	186	+}
	187	+#else
	188	+static inline struct rotary_encoder_platform_data *
	189	+rotary_encoder_parse_dt(struct device *dev)
	190	+{
	191	+ return NULL;
	192	+}
	193	+#endif
	194	+
143	195	static int __devinit rotary_encoder_probe(struct platform_device *pdev)
144	196	{
145	197	struct device *dev = &pdev->dev;
146	198
...	...	@@ -150,14 +202,19 @@
150	202	int err;
151	203
152	204	if (!pdata) {
153		- dev_err(&pdev->dev, "missing platform data\n");
154		- return -ENOENT;
	205	+ pdata = rotary_encoder_parse_dt(dev);
	206	+ if (IS_ERR(pdata))
	207	+ return PTR_ERR(pdata);
	208	+
	209	+ if (!pdata) {
	210	+ dev_err(dev, "missing platform data\n");
	211	+ return -EINVAL;
	212	+ }
155	213	}
156	214
157	215	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
158	216	input = input_allocate_device();
159	217	if (!encoder \|\| !input) {
160		- dev_err(&pdev->dev, "failed to allocate memory for device\n");
161	218	err = -ENOMEM;
162	219	goto exit_free_mem;
163	220	}
164	221
...	...	@@ -165,10 +222,9 @@
165	222	encoder->input = input;
166	223	encoder->pdata = pdata;
167	224
168		- /* create and register the input driver */
169	225	input->name = pdev->name;
170	226	input->id.bustype = BUS_HOST;
171		- input->dev.parent = &pdev->dev;
	227	+ input->dev.parent = dev;
172	228
173	229	if (pdata->relative_axis) {
174	230	input->evbit[0] = BIT_MASK(EV_REL);
175	231
...	...	@@ -179,17 +235,11 @@
179	235	pdata->axis, 0, pdata->steps, 0, 1);
180	236	}
181	237
182		- err = input_register_device(input);
183		- if (err) {
184		- dev_err(dev, "failed to register input device\n");
185		- goto exit_free_mem;
186		- }
187		-
188	238	/* request the GPIOs */
189	239	err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev));
190	240	if (err) {
191	241	dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a);
192		- goto exit_unregister_input;
	242	+ goto exit_free_mem;
193	243	}
194	244
195	245	err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev));
196	246
197	247
198	248
...	...	@@ -225,22 +275,30 @@
225	275	goto exit_free_irq_a;
226	276	}
227	277
	278	+ err = input_register_device(input);
	279	+ if (err) {
	280	+ dev_err(dev, "failed to register input device\n");
	281	+ goto exit_free_irq_b;
	282	+ }
	283	+
228	284	platform_set_drvdata(pdev, encoder);
229	285
230	286	return 0;
231	287
	288	+exit_free_irq_b:
	289	+ free_irq(encoder->irq_b, encoder);
232	290	exit_free_irq_a:
233	291	free_irq(encoder->irq_a, encoder);
234	292	exit_free_gpio_b:
235	293	gpio_free(pdata->gpio_b);
236	294	exit_free_gpio_a:
237	295	gpio_free(pdata->gpio_a);
238		-exit_unregister_input:
239		- input_unregister_device(input);
240		- input = NULL; /* so we don't try to free it */
241	296	exit_free_mem:
242	297	input_free_device(input);
243	298	kfree(encoder);
	299	+ if (!dev_get_platdata(&pdev->dev))
	300	+ kfree(pdata);
	301	+
244	302	return err;
245	303	}
246	304
247	305
248	306
...	...	@@ -253,10 +311,15 @@
253	311	free_irq(encoder->irq_b, encoder);
254	312	gpio_free(pdata->gpio_a);
255	313	gpio_free(pdata->gpio_b);
	314	+
256	315	input_unregister_device(encoder->input);
257		- platform_set_drvdata(pdev, NULL);
258	316	kfree(encoder);
259	317
	318	+ if (!dev_get_platdata(&pdev->dev))
	319	+ kfree(pdata);
	320	+
	321	+ platform_set_drvdata(pdev, NULL);
	322	+
260	323	return 0;
261	324	}
262	325
...	...	@@ -266,6 +329,7 @@
266	329	.driver = {
267	330	.name = DRV_NAME,
268	331	.owner = THIS_MODULE,
	332	+ .of_match_table = of_match_ptr(rotary_encoder_of_match),
269	333	}
270	334	};
271	335	module_platform_driver(rotary_encoder_driver);