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Message-ID: <20110130182540.GA12801@pengutronix.de>
Date: Sun, 30 Jan 2011 19:25:40 +0100
From: Wolfram Sang <w.sang@...gutronix.de>
To: Joachim Eastwood <manabian@...il.com>
Cc: rpurdie@...ys.net, riku.voipio@....fi,
linux-kernel@...r.kernel.org, joachim.eastwood@...ron.com
Subject: Re: [leds-pca9532] Add gpio capability
Hi,
> Since it is a bug to call get/set value on unrequested gpio's the
> check for PCA9532_TYPE_GPIO could be removed from
> pca9532_gpio_get_value/pca9532_gpio_set_value functions. But I have
> kept it for this posting.
If you keep it, you could print a warning maybe. Or just remove the check.
> -------------------------------------------------------------------
> [leds-pca9532] Add gpio capability
>
> Pins not used for leds can now be used as gpio by setting pin type as
> PCA9532_TYPE_GPIO and defining a gpio_base in platform data.
>
> Signed-off-by: Joachim Eastwood <joachim.eastwood@...ron.com>
Some Kconfig-magic is missing. Iff that feature is used, then it depends on
GENERIC_GPIO.
>
> diff --git a/drivers/leds/leds-pca9532.c b/drivers/leds/leds-pca9532.c
> index afac338..b036fa5 100644
> --- a/drivers/leds/leds-pca9532.c
> +++ b/drivers/leds/leds-pca9532.c
> @@ -19,7 +19,9 @@
> #include <linux/mutex.h>
> #include <linux/workqueue.h>
> #include <linux/leds-pca9532.h>
> +#include <linux/gpio.h>
>
> +#define PCA9532_REG_INPUT(i) ((i)/8)
> #define PCA9532_REG_PSC(i) (0x2+(i)*2)
> #define PCA9532_REG_PWM(i) (0x3+(i)*2)
> #define PCA9532_REG_LS0 0x6
> @@ -34,6 +36,7 @@ struct pca9532_data {
> struct mutex update_lock;
> struct input_dev *idev;
> struct work_struct work;
> + struct gpio_chip gpio;
> u8 pwm[2];
> u8 psc[2];
> };
> @@ -200,16 +203,58 @@ static void pca9532_led_work(struct work_struct *work)
> pca9532_setled(led);
> }
>
> -static void pca9532_destroy_devices(struct pca9532_data *data, int n_devs)
> +static int pca9532_gpio_request_pin(struct gpio_chip *gc, unsigned off)
Nitpick: maybe 'offset' as variable name? I first thought 'off' was a
description of the state.
> {
> - int i = n_devs;
> + struct pca9532_data *data = container_of(gc, struct pca9532_data, gpio);
> + struct pca9532_led *led = &data->leds[off];
> +
> + if (led->type == PCA9532_TYPE_GPIO)
> + return 0;
> +
> + return -EINVAL;
-EBUSY? The value is valid, just the pin is used already.
> +}
> +
> +static void pca9532_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
> +{
> + struct pca9532_data *data = container_of(gc, struct pca9532_data, gpio);
> + struct pca9532_led *led = &data->leds[off];
> +
> + if (led->type == PCA9532_TYPE_GPIO) {
> + if (val)
> + led->state = PCA9532_ON;
> + else
> + led->state = PCA9532_OFF;
> +
> + pca9532_setled(led);
> + }
> +}
> +
> +static int pca9532_gpio_get_value(struct gpio_chip *gc, unsigned off)
> +{
> + struct pca9532_data *data = container_of(gc, struct pca9532_data, gpio);
> + struct pca9532_led *led = &data->leds[off];
> + unsigned char reg;
> +
> + if (led->type == PCA9532_TYPE_GPIO) {
> + reg = i2c_smbus_read_byte_data(data->client,
> + PCA9532_REG_INPUT(off));
> + return !!(reg & (1<<(off % 8)));
Spaces around operators.
> + }
> +
> + return -1;
According to gpio.txt, you should return 0 here (there are no errorcodes).
> +}
> +
> +static int pca9532_destroy_devices(struct pca9532_data *data, int n_devs)
> +{
> + int err, i = n_devs;
>
> if (!data)
> - return;
> + return -EINVAL;
>
> while (--i >= 0) {
> switch (data->leds[i].type) {
> case PCA9532_TYPE_NONE:
> + case PCA9532_TYPE_GPIO:
> break;
> case PCA9532_TYPE_LED:
> led_classdev_unregister(&data->leds[i].ldev);
> @@ -224,12 +269,24 @@ static void pca9532_destroy_devices(struct
> pca9532_data *data, int n_devs)
> break;
> }
> }
> +
> + if (data->gpio.dev) {
> + err = gpiochip_remove(&data->gpio);
> + if (err) {
> + dev_err(&data->client->dev, "%s failed, %d\n",
> + "gpiochip_remove()", err);
> + return err;
> + }
> + }
> +
> + return 0;
> }
>
> static int pca9532_configure(struct i2c_client *client,
> struct pca9532_data *data, struct pca9532_platform_data *pdata)
> {
> int i, err = 0;
> + int gpios = 0;
>
> for (i = 0; i < 2; i++) {
> data->pwm[i] = pdata->pwm[i];
> @@ -249,6 +306,9 @@ static int pca9532_configure(struct i2c_client *client,
> switch (led->type) {
> case PCA9532_TYPE_NONE:
> break;
> + case PCA9532_TYPE_GPIO:
> + gpios++;
> + break;
> case PCA9532_TYPE_LED:
> led->state = pled->state;
> led->name = pled->name;
> @@ -297,6 +357,30 @@ static int pca9532_configure(struct i2c_client *client,
> break;
> }
> }
> +
> + if (gpios) {
> + data->gpio.label = "gpio-pca9532";
> + data->gpio.set = pca9532_gpio_set_value;
> + data->gpio.get = pca9532_gpio_get_value;
> + data->gpio.request = pca9532_gpio_request_pin;
> + data->gpio.can_sleep = 1;
> + data->gpio.base = pdata->gpio_base;
> + data->gpio.ngpio = 16;
> + data->gpio.dev = &client->dev;
> + data->gpio.owner = THIS_MODULE;
I'd assume that you also need to define a direction_output-function which always
returns success?
> +
> + err = gpiochip_add(&data->gpio);
> + if (err) {
> + /* Use data->gpio.dev as a flag for freeing gpiochip */
> + data->gpio.dev = NULL;
> + dev_info(&client->dev, "could not add gpiochip\n");
dev_warning?
> + } else {
> + dev_info(&client->dev, "gpios %i...%i\n",
> + data->gpio.base, data->gpio.base +
> + data->gpio.ngpio - 1);
> + }
> + }
> +
> return 0;
>
> exit:
> @@ -337,7 +421,12 @@ static int pca9532_probe(struct i2c_client *client,
> static int pca9532_remove(struct i2c_client *client)
> {
> struct pca9532_data *data = i2c_get_clientdata(client);
> - pca9532_destroy_devices(data, 16);
> + int err;
> +
> + err = pca9532_destroy_devices(data, 16);
> + if (err)
> + return err;
> +
> kfree(data);
> return 0;
> }
> diff --git a/include/linux/leds-pca9532.h b/include/linux/leds-pca9532.h
> index f158eb1..b8d6fff 100644
> --- a/include/linux/leds-pca9532.h
> +++ b/include/linux/leds-pca9532.h
> @@ -25,7 +25,7 @@ enum pca9532_state {
> };
>
> enum pca9532_type { PCA9532_TYPE_NONE, PCA9532_TYPE_LED,
> - PCA9532_TYPE_N2100_BEEP };
> + PCA9532_TYPE_N2100_BEEP, PCA9532_TYPE_GPIO };
>
> struct pca9532_led {
> u8 id;
> @@ -41,6 +41,7 @@ struct pca9532_platform_data {
> struct pca9532_led leds[16];
> u8 pwm[2];
> u8 psc[2];
> + int gpio_base;
> };
>
> #endif /* __LINUX_PCA9532_H */
> --
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Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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