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linux/drivers/auxdisplay/lcd2s.c
Uwe Kleine-König ed5c2f5fd1 i2c: Make remove callback return void 
The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2022-08-16 12:46:26 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Console driver for LCD2S 4x20 character displays connected through i2c.
* The display also has a SPI interface, but the driver does not support
* this yet.
*
* This is a driver allowing you to use a LCD2S 4x20 from Modtronix
* engineering as auxdisplay character device.
*
* (C) 2019 by Lemonage Software GmbH
* Author: Lars Pöschel <poeschel@lemonage.de>
* All rights reserved.
*/
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include "charlcd.h"
#define LCD2S_CMD_CUR_MOVES_FWD 0x09
#define LCD2S_CMD_CUR_BLINK_OFF 0x10
#define LCD2S_CMD_CUR_UL_OFF 0x11
#define LCD2S_CMD_DISPLAY_OFF 0x12
#define LCD2S_CMD_CUR_BLINK_ON 0x18
#define LCD2S_CMD_CUR_UL_ON 0x19
#define LCD2S_CMD_DISPLAY_ON 0x1a
#define LCD2S_CMD_BACKLIGHT_OFF 0x20
#define LCD2S_CMD_BACKLIGHT_ON 0x28
#define LCD2S_CMD_WRITE 0x80
#define LCD2S_CMD_MOV_CUR_RIGHT 0x83
#define LCD2S_CMD_MOV_CUR_LEFT 0x84
#define LCD2S_CMD_SHIFT_RIGHT 0x85
#define LCD2S_CMD_SHIFT_LEFT 0x86
#define LCD2S_CMD_SHIFT_UP 0x87
#define LCD2S_CMD_SHIFT_DOWN 0x88
#define LCD2S_CMD_CUR_ADDR 0x89
#define LCD2S_CMD_CUR_POS 0x8a
#define LCD2S_CMD_CUR_RESET 0x8b
#define LCD2S_CMD_CLEAR 0x8c
#define LCD2S_CMD_DEF_CUSTOM_CHAR 0x92
#define LCD2S_CMD_READ_STATUS 0xd0
#define LCD2S_CHARACTER_SIZE 8
#define LCD2S_STATUS_BUF_MASK 0x7f
struct lcd2s_data {
struct i2c_client *i2c;
struct charlcd *charlcd;
};
static s32 lcd2s_wait_buf_free(const struct i2c_client *client, int count)
{
s32 status;
status = i2c_smbus_read_byte_data(client, LCD2S_CMD_READ_STATUS);
if (status < 0)
return status;
while ((status & LCD2S_STATUS_BUF_MASK) < count) {
mdelay(1);
status = i2c_smbus_read_byte_data(client,
LCD2S_CMD_READ_STATUS);
if (status < 0)
return status;
}
return 0;
}
static int lcd2s_i2c_master_send(const struct i2c_client *client,
const char *buf, int count)
{
s32 status;
status = lcd2s_wait_buf_free(client, count);
if (status < 0)
return status;
return i2c_master_send(client, buf, count);
}
static int lcd2s_i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
{
s32 status;
status = lcd2s_wait_buf_free(client, 1);
if (status < 0)
return status;
return i2c_smbus_write_byte(client, value);
}
static int lcd2s_print(struct charlcd *lcd, int c)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
u8 buf[2] = { LCD2S_CMD_WRITE, c };
lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
return 0;
}
static int lcd2s_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
u8 buf[3] = { LCD2S_CMD_CUR_POS, y + 1, x + 1 };
lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
return 0;
}
static int lcd2s_home(struct charlcd *lcd)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_RESET);
return 0;
}
static int lcd2s_init_display(struct charlcd *lcd)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
/* turn everything off, but display on */
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_MOVES_FWD);
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
return 0;
}
static int lcd2s_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
if (dir == CHARLCD_SHIFT_LEFT)
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_LEFT);
else
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_RIGHT);
return 0;
}
static int lcd2s_shift_display(struct charlcd *lcd, enum charlcd_shift_dir dir)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
if (dir == CHARLCD_SHIFT_LEFT)
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_LEFT);
else
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_RIGHT);
return 0;
}
static void lcd2s_backlight(struct charlcd *lcd, enum charlcd_onoff on)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
if (on)
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_ON);
else
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
}
static int lcd2s_display(struct charlcd *lcd, enum charlcd_onoff on)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
if (on)
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
else
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_OFF);
return 0;
}
static int lcd2s_cursor(struct charlcd *lcd, enum charlcd_onoff on)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
if (on)
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_ON);
else
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
return 0;
}
static int lcd2s_blink(struct charlcd *lcd, enum charlcd_onoff on)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
if (on)
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_ON);
else
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
return 0;
}
static int lcd2s_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
{
return 0;
}
static int lcd2s_lines(struct charlcd *lcd, enum charlcd_lines lines)
{
return 0;
}
/*
* Generator: LGcxxxxx...xx; must have <c> between '0' and '7',
* representing the numerical ASCII code of the redefined character,
* and <xx...xx> a sequence of 16 hex digits representing 8 bytes
* for each character. Most LCDs will only use 5 lower bits of
* the 7 first bytes.
*/
static int lcd2s_redefine_char(struct charlcd *lcd, char *esc)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
u8 buf[LCD2S_CHARACTER_SIZE + 2] = { LCD2S_CMD_DEF_CUSTOM_CHAR };
u8 value;
int shift, i;
if (!strchr(esc, ';'))
return 0;
esc++;
buf[1] = *(esc++) - '0';
if (buf[1] > 7)
return 1;
i = 2;
shift = 0;
value = 0;
while (*esc && i < LCD2S_CHARACTER_SIZE + 2) {
int half;
shift ^= 4;
half = hex_to_bin(*esc++);
if (half < 0)
continue;
value |= half << shift;
if (shift == 0) {
buf[i++] = value;
value = 0;
}
}
lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
return 1;
}
static int lcd2s_clear_display(struct charlcd *lcd)
{
struct lcd2s_data *lcd2s = lcd->drvdata;
/* This implicitly sets cursor to first row and column */
lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
return 0;
}
static const struct charlcd_ops lcd2s_ops = {
.print = lcd2s_print,
.backlight = lcd2s_backlight,
.gotoxy = lcd2s_gotoxy,
.home = lcd2s_home,
.clear_display = lcd2s_clear_display,
.init_display = lcd2s_init_display,
.shift_cursor = lcd2s_shift_cursor,
.shift_display = lcd2s_shift_display,
.display = lcd2s_display,
.cursor = lcd2s_cursor,
.blink = lcd2s_blink,
.fontsize = lcd2s_fontsize,
.lines = lcd2s_lines,
.redefine_char = lcd2s_redefine_char,
};
static int lcd2s_i2c_probe(struct i2c_client *i2c)
{
struct charlcd *lcd;
struct lcd2s_data *lcd2s;
int err;
if (!i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
return -EIO;
lcd2s = devm_kzalloc(&i2c->dev, sizeof(*lcd2s), GFP_KERNEL);
if (!lcd2s)
return -ENOMEM;
/* Test, if the display is responding */
err = lcd2s_i2c_smbus_write_byte(i2c, LCD2S_CMD_DISPLAY_OFF);
if (err < 0)
return err;
lcd = charlcd_alloc();
if (!lcd)
return -ENOMEM;
lcd->drvdata = lcd2s;
lcd2s->i2c = i2c;
lcd2s->charlcd = lcd;
/* Required properties */
err = device_property_read_u32(&i2c->dev, "display-height-chars",
&lcd->height);
if (err)
goto fail1;
err = device_property_read_u32(&i2c->dev, "display-width-chars",
&lcd->width);
if (err)
goto fail1;
lcd->ops = &lcd2s_ops;
err = charlcd_register(lcd2s->charlcd);
if (err)
goto fail1;
i2c_set_clientdata(i2c, lcd2s);
return 0;
fail1:
charlcd_free(lcd2s->charlcd);
return err;
}
static void lcd2s_i2c_remove(struct i2c_client *i2c)
{
struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
charlcd_unregister(lcd2s->charlcd);
charlcd_free(lcd2s->charlcd);
}
static const struct i2c_device_id lcd2s_i2c_id[] = {
{ "lcd2s", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, lcd2s_i2c_id);
static const struct of_device_id lcd2s_of_table[] = {
{ .compatible = "modtronix,lcd2s" },
{ }
};
MODULE_DEVICE_TABLE(of, lcd2s_of_table);
static struct i2c_driver lcd2s_i2c_driver = {
.driver = {
.name = "lcd2s",
.of_match_table = lcd2s_of_table,
},
.probe_new = lcd2s_i2c_probe,
.remove = lcd2s_i2c_remove,
.id_table = lcd2s_i2c_id,
};
module_i2c_driver(lcd2s_i2c_driver);
MODULE_DESCRIPTION("LCD2S character display driver");
MODULE_AUTHOR("Lars Poeschel");
MODULE_LICENSE("GPL");
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