Hi, Michael,

Thanks for your comments, I agree with you, it's a better way to
export only the spare pins as GPIO.
I update this patch, any comments and suggestion, feel free let me know.

Patch:

From 027a344b0fc49f87edd325d5896c3d0985ec5869 Mon Sep 17 00:00:00 2001
From: Xiaolong Chen <redacted>
Date: Sat, 17 Jul 2010 03:18:28 +0800
Subject: [PATCH] Input: ADP5588 - Support gpio function on unused pin

This implements an optional gpio function on unused pin by adp5588
kpad.

adp5588_kpad_platform_data has been extended with support_gpio,
support gpio function if it equals 1, and gpio_start, the gpio chip
base for this module.

Signed-off-by: Xiaolong Chen <redacted>
Signed-off-by: Yuanbo Ye <redacted>
Signed-off-by: Tao Hu <redacted>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/input/keyboard/adp5588-keys.c |  144 +++++++++++++++++++++++++++++++++
 include/linux/i2c/adp5588.h           |    2 +
 2 files changed, 146 insertions(+), 0 deletions(-)

diff --git a/drivers/input/keyboard/adp5588-keys.c

b/drivers/input/keyboard/adp5588-keys.c
index 3c8876a..ed18c93 100644

--- a/drivers/input/keyboard/adp5588-keys.c
+++ b/drivers/input/keyboard/adp5588-keys.c

@@ -18,6 +18,7 @@
 #include <linux/platform_device.h>
 #include <linux/input.h>
 #include <linux/i2c.h>
+#include <linux/gpio.h>

 #include <linux/i2c/adp5588.h>

@@ -52,6 +53,10 @@

 #define KEYP_MAX_EVENT		10

+#define MAXGPIO			18
+#define ADP_BANK(offs)		((offs) >> 3)
+#define ADP_BIT(offs)		(1u << ((offs) & 0x7))
+
 /*
  * Early pre 4.0 Silicon required to delay readout by at least 25ms,
  * since the Event Counter Register updated 25ms after the interrupt

@@ -67,6 +72,12 @@ struct adp5588_kpad {
 	unsigned short keycode[ADP5588_KEYMAPSIZE];
 	const struct adp5588_gpi_map *gpimap;
 	unsigned short gpimapsize;
+	unsigned char gpiomap[MAXGPIO];
+	unsigned support_gpio;
+	struct gpio_chip gpio_chip;
+	struct mutex gpio_lock;	/* Protect cached dir, dat_out */
+	uint8_t dat_out[3];
+	uint8_t dir[3];
 };

 static int adp5588_read(struct i2c_client *client, u8 reg)

@@ -84,6 +95,85 @@ static int adp5588_write(struct i2c_client *client,

u8 reg, u8 val)
 	return i2c_smbus_write_byte_data(client, reg, val);
 }

+static int adp5588_gpio_get_value(struct gpio_chip *chip, unsigned off)
+{
+	unsigned bank, bit;
+	struct adp5588_kpad *dev =
+	    container_of(chip, struct adp5588_kpad, gpio_chip);
+
+	bank = ADP_BANK(dev->gpiomap[off]);
+	bit = ADP_BIT(dev->gpiomap[off]);
+
+	return !!(adp5588_read(dev->client, GPIO_DAT_STAT1 + bank) & bit);
+}
+
+static void adp5588_gpio_set_value(struct gpio_chip *chip,
+				   unsigned off, int val)
+{
+	unsigned bank, bit;
+	struct adp5588_kpad *dev =
+	    container_of(chip, struct adp5588_kpad, gpio_chip);
+
+	bank = ADP_BANK(dev->gpiomap[off]);
+	bit = ADP_BIT(dev->gpiomap[off]);
+
+	mutex_lock(&dev->gpio_lock);
+	if (val)
+		dev->dat_out[bank] |= bit;
+	else
+		dev->dat_out[bank] &= ~bit;
+
+	adp5588_write(dev->client, GPIO_DAT_OUT1 + bank,
+			   dev->dat_out[bank]);
+	mutex_unlock(&dev->gpio_lock);
+}
+
+static int adp5588_gpio_direction_input(struct gpio_chip *chip, unsigned off)
+{
+	int ret;
+	unsigned bank, bit;
+	struct adp5588_kpad *dev =
+	    container_of(chip, struct adp5588_kpad, gpio_chip);
+
+	bank = ADP_BANK(dev->gpiomap[off]);
+	bit = ADP_BIT(dev->gpiomap[off]);
+
+	mutex_lock(&dev->gpio_lock);
+	dev->dir[bank] &= ~bit;
+	ret = adp5588_write(dev->client, GPIO_DIR1 + bank, dev->dir[bank]);
+	mutex_unlock(&dev->gpio_lock);
+
+	return ret;
+}
+
+static int adp5588_gpio_direction_output(struct gpio_chip *chip,
+					 unsigned off, int val)
+{
+	int ret;
+	unsigned bank, bit;
+	struct adp5588_kpad *dev =
+	    container_of(chip, struct adp5588_kpad, gpio_chip);
+
+	bank = ADP_BANK(dev->gpiomap[off]);
+	bit = ADP_BIT(dev->gpiomap[off]);
+
+	mutex_lock(&dev->gpio_lock);
+	dev->dir[bank] |= bit;
+
+	if (val)
+		dev->dat_out[bank] |= bit;
+	else
+		dev->dat_out[bank] &= ~bit;
+
+	ret = adp5588_write(dev->client, GPIO_DAT_OUT1 + bank,
+				 dev->dat_out[bank]);
+	ret |= adp5588_write(dev->client, GPIO_DIR1 + bank,
+				 dev->dir[bank]);
+	mutex_unlock(&dev->gpio_lock);
+
+	return ret;
+}
+
 static void adp5588_work(struct work_struct *work)
 {
 	struct adp5588_kpad *kpad = container_of(work,

@@ -204,6 +294,7 @@ static int __devinit adp5588_probe(struct

i2c_client *client,
 	int ret, i;
 	int error;
 	int gpi_stat1 = 0, gpi_stat2 = 0, gpi_stat3 = 0;
+	struct gpio_chip *gc;

 	if (!i2c_check_functionality(client->adapter,
 					I2C_FUNC_SMBUS_BYTE_DATA)) {

@@ -273,6 +364,24 @@ static int __devinit adp5588_probe(struct

i2c_client *client,
 	kpad->input = input;
 	INIT_DELAYED_WORK(&kpad->work, adp5588_work);

+	kpad->support_gpio = pdata->support_gpio;
+
+	if (kpad->support_gpio) {
+		gc = &kpad->gpio_chip;
+		gc->direction_input = adp5588_gpio_direction_input;
+		gc->direction_output = adp5588_gpio_direction_output;
+		gc->get = adp5588_gpio_get_value;
+		gc->set = adp5588_gpio_set_value;
+		gc->can_sleep = 1;
+
+		gc->base = pdata->gpio_start;
+		gc->ngpio = MAXGPIO;
+		gc->label = client->name;
+		gc->owner = THIS_MODULE;
+
+		mutex_init(&kpad->gpio_lock);
+	}
+
 	ret = adp5588_read(client, DEV_ID);
 	if (ret < 0) {
 		error = ret;

@@ -340,6 +449,38 @@ static int __devinit adp5588_probe(struct

i2c_client *client,
 	device_init_wakeup(&client->dev, 1);
 	i2c_set_clientdata(client, kpad);

+	if (kpad->support_gpio) {
+		int j = 0;
+		unsigned char pin_used[MAXGPIO];
+
+		for (i = 0; i < pdata->rows; i++)
+			pin_used[i] = 1;
+
+		for (i = 0; i < pdata->cols; i++)
+			pin_used[i + GPI_PIN_COL_BASE - GPI_PIN_BASE] = 1;
+
+		for (i = 0; i < kpad->gpimapsize; i++)
+			pin_used[kpad->gpimap[i].pin - GPI_PIN_BASE] = 1;
+
+		for (i = 0; i < MAXGPIO; i++) {
+			if (!pin_used[i])
+				kpad->gpiomap[j++] = i;
+		}
+		kpad->gpio_chip.ngpio = j;
+
+		ret = gpiochip_add(&kpad->gpio_chip);
+		if (ret) {
+			dev_err(&client->dev, "gpiochip_add err: %d\n", ret);
+			goto err_free_irq;
+		}
+
+		for (i = 0; i <= ADP_BANK(MAXGPIO); i++) {
+			kpad->dat_out[i] = adp5588_read(client,
+						GPIO_DAT_OUT1 + i);
+			kpad->dir[i] = adp5588_read(client, GPIO_DIR1 + i);
+		}
+	}
+
 	if (kpad->gpimapsize) {
 		gpi_stat1 = adp5588_read(client, GPIO_DAT_STAT1);
 		gpi_stat2 = adp5588_read(client, GPIO_DAT_STAT2);

@@ -389,12 +530,15 @@ static int __devinit adp5588_probe(struct

i2c_client *client,

 static int __devexit adp5588_remove(struct i2c_client *client)
 {
+	int ret;
 	struct adp5588_kpad *kpad = i2c_get_clientdata(client);

 	adp5588_write(client, CFG, 0);
 	free_irq(client->irq, kpad);
 	cancel_delayed_work_sync(&kpad->work);
 	input_unregister_device(kpad->input);
+	if (kpad->support_gpio)
+		ret = gpiochip_remove(&kpad->gpio_chip);
 	i2c_set_clientdata(client, NULL);
 	kfree(kpad);

diff --git a/include/linux/i2c/adp5588.h b/include/linux/i2c/adp5588.h
index a00686c..35078c3 100644
--- a/include/linux/i2c/adp5588.h
+++ b/include/linux/i2c/adp5588.h

@@ -123,6 +123,8 @@ struct adp5588_kpad_platform_data {
 	unsigned short unlock_key2;	/* Unlock Key 2 */
 	const struct adp5588_gpi_map *gpimap;
 	unsigned short gpimapsize;
+	unsigned support_gpio:1;	/* Support gpio on unused pin */
+	unsigned gpio_start;
 };

 #endif

-- 
1.7.0.4

Thanks,
Xiaolong

On Fri, Jul 16, 2010 at 4:48 PM, Hennerich, Michael
<Michael.Hennerich@analog.com> wrote:
> Xiaolong CHEN wrote on 2010-07-16:
>> Hi, Michael and Dmitry
>>
>> Do you have any comments and suggestion?
>
> Hi Xiaolong,
>
> First of all - great idea to export unused pins as GPIOs.
> This closed the gap between adp5588-gpio and adp5588-keys.
>
> But I wonder why you gpio_request() and free inside the driver.
> I would export only the spare pins as GPIO. I see that this will
> complicate things a little bit by adding some mapping.
> But first exporting as GPIO and then reserving them by
> gpio_request doesn't look like a straight approach.
>
> If no one else complains (adding David) I'm fine with the way it is now.
>
> Acked-by: Michael Hennerich <michael.hennerich@analog.com>
>
> Greetings,
> Michael
>
> Analog Devices GmbH      Wilhelm-Wagenfeld-Str. 6      80807 Muenchen
> Sitz der Gesellschaft Muenchen, Registergericht Muenchen HRB 4036 Geschaeftsfuehrer Thomas Wessel, William A. Martin, Margaret Seif
>
>
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