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    SubjectRe: [PATCH v2] input: add driver support for Sharp gp2ap002a00f proximity sensor
    Hi again Dmitry,

    Just a quick question before I post v3.

    On 18:03 Mon 14 Nov , Dmitry Torokhov wrote:
    > Hi Courtney,
    >
    > On Mon, Nov 14, 2011 at 04:39:18PM +0100, oskar.andero@sonyericsson.com wrote:
    > > From: Courtney Cavin <courtney.cavin@sonyericsson.com>
    > >
    >
    > The driver looks much better, a few more comments still.
    >
    > > +
    > > +#include <linux/i2c.h>
    > > +#include <linux/irq.h>
    > > +#include <linux/slab.h>
    > > +#include <linux/input.h>
    > > +#include <linux/module.h>
    > > +#include <linux/workqueue.h>
    >
    > As Shubhrajyoti mentioned workqueue.h is probably not needed.
    >
    > > +#include <linux/interrupt.h>
    > > +#include <linux/gpio.h>
    > > +#include <linux/delay.h>
    > > +#include <linux/input/gp2ap002a00f.h>
    > > +
    > > +struct gp2a_data {
    > > + struct input_dev *device;
    > > + const struct gp2a_platform_data *pdata;
    > > + struct i2c_client *i2c_client;
    > > +};
    > > +
    > > +enum gp2a_addr {
    > > + GP2A_ADDR_PROX = 0x0,
    > > + GP2A_ADDR_GAIN = 0x1,
    > > + GP2A_ADDR_HYS = 0x2,
    > > + GP2A_ADDR_CYCLE = 0x3,
    > > + GP2A_ADDR_OPMOD = 0x4,
    > > + GP2A_ADDR_CON = 0x6
    > > +};
    > > +
    > > +enum gp2a_controls {
    > > + GP2A_CTRL_SSD = 0x01
    > > +};
    > > +
    > > +static int gp2a_enable(struct gp2a_data *dt)
    > > +{
    > > + return i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_OPMOD,
    > > + GP2A_CTRL_SSD);
    > > +}
    > > +
    > > +static int gp2a_disable(struct gp2a_data *dt)
    > > +{
    > > + return i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_OPMOD,
    > > + 0x00);
    > > +}
    > > +
    > > +static int __devinit gp2a_initialize(struct gp2a_data *dt)
    > > +{
    > > + int error;
    > > +
    > > + error = i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_GAIN,
    > > + 0x08);
    > > + if (error < 0)
    > > + return error;
    > > +
    > > + error = i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_HYS,
    > > + 0xc2);
    > > + if (error < 0)
    > > + return error;
    > > +
    > > + error = i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_CYCLE,
    > > + 0x04);
    > > + if (error < 0)
    > > + return error;
    > > +
    > > + error = gp2a_disable(dt);
    > > +
    > > + return error;
    > > +}
    > > +
    > > +static int gp2a_report(struct gp2a_data *dt)
    > > +{
    > > + int vo = gpio_get_value(dt->pdata->vout_gpio);
    > > +
    > > + input_report_key(dt->device, SW_FRONT_PROXIMITY, !vo);
    >
    > Switch is not a key, so please use input_report_switch().
    >
    > > + input_sync(dt->device);
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static irqreturn_t gp2a_irq(int irq, void *handle)
    > > +{
    > > + struct gp2a_data *dt = handle;
    > > +
    > > + gp2a_report(dt);
    > > +
    > > + return IRQ_HANDLED;
    > > +}
    > > +
    > > +static int gp2a_device_open(struct input_dev *dev)
    > > +{
    > > + struct gp2a_data *dt = input_get_drvdata(dev);
    > > + int error;
    > > +
    > > + error = gp2a_enable(dt);
    > > + if (error < 0) {
    > > + dev_err(&dev->dev, "unable to activate, err %d\n", error);
    > > + return error;
    > > + }
    > > +
    > > + gp2a_report(dt);
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static void gp2a_device_close(struct input_dev *dev)
    > > +{
    > > + struct gp2a_data *dt = input_get_drvdata(dev);
    > > + int error;
    > > +
    > > + error = gp2a_disable(dt);
    > > + if (error < 0)
    > > + dev_err(&dev->dev, "unable to deactivate, err %d\n", error);
    > > +}
    > > +
    > > +static int __devinit gp2a_probe(struct i2c_client *client,
    > > + const struct i2c_device_id *id)
    > > +{
    > > + const struct gp2a_platform_data *pdata;
    > > + struct gp2a_data *dt;
    > > + int error;
    > > +
    > > + pdata = client->dev.platform_data;
    > > + if (!pdata)
    > > + return -EINVAL;
    > > +
    > > + if (pdata->hw_setup) {
    > > + error = pdata->hw_setup(client);
    > > + if (error < 0)
    > > + return error;
    > > + }
    > > +
    > > + error = gpio_direction_input(pdata->vout_gpio);
    > > + if (error < 0)
    > > + goto err_hw_shutdown;
    > > +
    > > + dt = kzalloc(sizeof(struct gp2a_data), GFP_KERNEL);
    > > + if (!dt) {
    > > + error = -ENOMEM;
    > > + goto err_hw_shutdown;
    > > + }
    > > +
    > > + dt->pdata = pdata;
    > > + dt->i2c_client = client;
    > > + i2c_set_clientdata(client, dt);
    > > +
    > > + error = gp2a_initialize(dt);
    > > + if (error < 0)
    > > + goto err_free_dt;
    > > +
    > > + dt->device = input_allocate_device();
    > > + if (!dt->device) {
    > > + error = -ENOMEM;
    > > + goto err_free_dt;
    > > + }
    > > + input_set_drvdata(dt->device, dt);
    > > +
    > > + error = request_threaded_irq(client->irq, NULL,
    > > + gp2a_irq, IRQF_TRIGGER_RISING |
    > > + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
    > > + GP2A_I2C_NAME, dt);
    > > + if (error) {
    > > + dev_err(&dt->device->dev, "irq request failed\n");
    >
    > You are leaking dt->device here. Please add a separate label for
    > input_free_device(dt->device).
    >
    > > + goto err_free_dt;
    > > + }
    > > +
    > > + dt->device->open = gp2a_device_open;
    > > + dt->device->close = gp2a_device_close;
    > > + dt->device->name = GP2A_I2C_NAME;
    > > + dt->device->id.bustype = BUS_I2C;
    > > +
    > > + input_set_capability(dt->device, EV_KEY, SW_FRONT_PROXIMITY);
    >
    > Should be EV_SW instead of EV_KEY.
    >
    > > +
    > > + error = input_register_device(dt->device);
    > > + if (error) {
    > > + dev_err(&dt->device->dev, "device registration failed\n");
    > > + input_free_device(dt->device);
    >
    > If you swap request_threaded_irq() and input_register_device() so that
    > registration is the last action error handling will be much simpler.
    >

    I am getting a bit confused here, since you asked me to swap the order
    of request_threaded_irq() and input_register_device() in my previous
    version as well. Swapping again will take us back to square one or maybe
    I am misinterpreting your comment?

    Anyways, this is what I am planning to do for v3:

    error = input_register_device(dt->device);
    if (error) {
    ...
    goto err_free_dt;
    }
    ...
    error = request_threaded_irq(client->irq, NULL, ...
    if (error) {
    ...
    goto err_free_unregister;
    }
    ...
    err_free_unregister:
    input_unregister_device(dt->device);
    err_free_dt:
    kfree(dt);
    err_hw_shutdown:
    if (pdata->hw_shutdown)
    pdata->hw_shutdown(client);
    return error;

    The above takes care of the leaking input_device and keeps the error handling
    pretty compact.
    Does this sound reasonable?

    -Oskar


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