Re: [PATCH] video console: add a driver for lcd2s character display

From: Arnd Bergmann
Date: Tue Nov 20 2012 - 08:25:56 EST


On Tuesday 20 November 2012, Lars Poeschel wrote:
> From: Lars Poeschel <poeschel@xxxxxxxxxxx>
>
> This driver allows to use a lcd2s 20x4 character display as
> a linux console output device.
>
> Signed-off-by: Lars Poeschel <poeschel@xxxxxxxxxxx>

The driver looks nice overall, but I found two style issues:

> +static int __devinit lcd2s_i2c_probe(struct i2c_client *i2c,
> + const struct i2c_device_id *id)
> +{
> + struct lcd2s_data *data;
> +
> + if (!i2c_check_functionality(i2c->adapter,
> + I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
> + return -EIO;
> + data = devm_kzalloc(&i2c->dev, sizeof(struct lcd2s_data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->i2c = i2c;
> + data->consw.owner = THIS_MODULE;
> + data->consw.con_startup = lcd2s_startup;
> + data->consw.con_init = lcd2s_init;
> + data->consw.con_deinit = lcd2s_deinit;
> + data->consw.con_clear = lcd2s_clear;
> + data->consw.con_putc = lcd2s_putc;
> + data->consw.con_putcs = lcd2s_putcs;
> + data->consw.con_cursor = lcd2s_cursor;
> + data->consw.con_scroll = lcd2s_scroll;
> + data->consw.con_bmove = lcd2s_bmove;
> + data->consw.con_switch = lcd2s_switch;
> + data->consw.con_blank = lcd2s_blank;
> + data->consw.con_set_palette = lcd2s_set_palette;
> + data->consw.con_scrolldelta = lcd2s_scrolldelta;
> +
> + i2c_set_clientdata(i2c, data);
> +
> + take_over_console(&data->consw, LCD2S_FIRST, LCD2S_LAST, 1);
> +
> + return 0;
> +}

It's better to define the struct consw as a preinitialized
'static const' object, rather than dynamically setting each
member.

> +static struct i2c_driver lcd2s_i2c_driver = {
> + .driver = {
> + .name = "lcd2s",
> + .owner = THIS_MODULE,
> + },
> + .probe = lcd2s_i2c_probe,
> + .remove = __devexit_p(lcd2s_i2c_remove),
> + .id_table = lcd2s_i2c_id,
> +};
> +
> +static int __init lcd2s_modinit(void)
> +{
> + int ret = 0;
> +
> + ret = i2c_add_driver(&lcd2s_i2c_driver);
> + if (ret != 0)
> + pr_err("Failed to register lcd2s driver\n");
> +
> + return ret;
> +}
> +module_init(lcd2s_modinit)
> +
> +static void __exit lcd2s_exit(void)
> +{
> + i2c_del_driver(&lcd2s_i2c_driver);
> +}
> +module_exit(lcd2s_exit)

Here, you can use module_i2c_driver.

Arnd

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