linux-kernel - [PATCH 2/2 v2] gpio/stmpe: support no-irq mode

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Date:	Thu, 26 Jan 2012 22:17:15 +0100
From:	Linus Walleij <linus.walleij@...ricsson.com>
To:	Samuel Ortiz <sameo@...ux.intel.com>,
	<linux-kernel@...r.kernel.org>
Cc:	Viresh Kumar <viresh.kumar@...com>,
	Chris Blair <chris.blair@...ricsson.com>,
	Grant Likely <grant.likely@...retlab.ca>
Subject: [PATCH 2/2 v2] gpio/stmpe: support no-irq mode

From: Chris Blair <chris.blair@...ricsson.com>

Adds support for boards which have an STMPE GPIO device without the
interrupt pin connected. This means that no interrupt can be received
but the GPIO pins can still be driven and read.

Cc: Grant Likely <grant.likely@...retlab.ca>
Acked-by: Viresh Kumar <viresh.kumar@...com>
Tested-by: Michel Jaouen <michel.jaouen@...ricsson.com>
Signed-off-by: Chris Blair <chris.blair@...ricsson.com>
---
ChangeLog v1->v2:
- Removes the use of the new no_irq platform data member and
  instead uses the value obtained for the cell irq to know if irqs
  are supported or not. If irqs are not supported, the device
  will not have been given an irq resource and the irq value
  will be invalid.

This depends on the previous patch to the MFD
code so should better be merged into the MFD tree with the
previous patch.
---
 drivers/gpio/gpio-stmpe.c |   41 +++++++++++++++++++++++++----------------
 1 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index 87a68a8..094c5c4 100644
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -307,13 +307,11 @@ static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
 	struct stmpe_gpio_platform_data *pdata;
 	struct stmpe_gpio *stmpe_gpio;
 	int ret;
-	int irq;
+	int irq = 0;
 
 	pdata = stmpe->pdata->gpio;
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq < 0)
-		return irq;
 
 	stmpe_gpio = kzalloc(sizeof(struct stmpe_gpio), GFP_KERNEL);
 	if (!stmpe_gpio)
@@ -330,21 +328,28 @@ static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
 	stmpe_gpio->chip.dev = &pdev->dev;
 	stmpe_gpio->chip.base = pdata ? pdata->gpio_base : -1;
 
-	stmpe_gpio->irq_base = stmpe->irq_base + STMPE_INT_GPIO(0);
+	if (irq >= 0)
+		stmpe_gpio->irq_base = stmpe->irq_base + STMPE_INT_GPIO(0);
+	else
+		dev_info(&pdev->dev,
+			"device configured in no-irq mode; "
+			"irqs are not available\n");
 
 	ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
 	if (ret)
 		goto out_free;
 
-	ret = stmpe_gpio_irq_init(stmpe_gpio);
-	if (ret)
-		goto out_disable;
+	if (irq >= 0) {
+		ret = stmpe_gpio_irq_init(stmpe_gpio);
+		if (ret)
+			goto out_disable;
 
-	ret = request_threaded_irq(irq, NULL, stmpe_gpio_irq, IRQF_ONESHOT,
-				   "stmpe-gpio", stmpe_gpio);
-	if (ret) {
-		dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
-		goto out_removeirq;
+		ret = request_threaded_irq(irq, NULL, stmpe_gpio_irq,
+				IRQF_ONESHOT, "stmpe-gpio", stmpe_gpio);
+		if (ret) {
+			dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
+			goto out_removeirq;
+		}
 	}
 
 	ret = gpiochip_add(&stmpe_gpio->chip);
@@ -361,9 +366,11 @@ static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
 	return 0;
 
 out_freeirq:
-	free_irq(irq, stmpe_gpio);
+	if (irq >= 0)
+		free_irq(irq, stmpe_gpio);
 out_removeirq:
-	stmpe_gpio_irq_remove(stmpe_gpio);
+	if (irq >= 0)
+		stmpe_gpio_irq_remove(stmpe_gpio);
 out_disable:
 	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 out_free:
@@ -391,8 +398,10 @@ static int __devexit stmpe_gpio_remove(struct platform_device *pdev)
 
 	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 
-	free_irq(irq, stmpe_gpio);
-	stmpe_gpio_irq_remove(stmpe_gpio);
+	if (irq >= 0) {
+		free_irq(irq, stmpe_gpio);
+		stmpe_gpio_irq_remove(stmpe_gpio);
+	}
 	platform_set_drvdata(pdev, NULL);
 	kfree(stmpe_gpio);
 
-- 
1.7.8

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