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linux/drivers/video/backlight/ili922x.c
Uwe Kleine-König a0386bba70
spi: make remove callback a void function 
The value returned by an spi 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.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-09 13:00:45 +00:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* (C) Copyright 2008
* Stefano Babic, DENX Software Engineering, sbabic@denx.de.
*
* This driver implements a lcd device for the ILITEK 922x display
* controller. The interface to the display is SPI and the display's
* memory is cyclically updated over the RGB interface.
*/
#include <linux/fb.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/lcd.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/string.h>
/* Register offset, see manual section 8.2 */
#define REG_START_OSCILLATION 0x00
#define REG_DRIVER_CODE_READ 0x00
#define REG_DRIVER_OUTPUT_CONTROL 0x01
#define REG_LCD_AC_DRIVEING_CONTROL 0x02
#define REG_ENTRY_MODE 0x03
#define REG_COMPARE_1 0x04
#define REG_COMPARE_2 0x05
#define REG_DISPLAY_CONTROL_1 0x07
#define REG_DISPLAY_CONTROL_2 0x08
#define REG_DISPLAY_CONTROL_3 0x09
#define REG_FRAME_CYCLE_CONTROL 0x0B
#define REG_EXT_INTF_CONTROL 0x0C
#define REG_POWER_CONTROL_1 0x10
#define REG_POWER_CONTROL_2 0x11
#define REG_POWER_CONTROL_3 0x12
#define REG_POWER_CONTROL_4 0x13
#define REG_RAM_ADDRESS_SET 0x21
#define REG_WRITE_DATA_TO_GRAM 0x22
#define REG_RAM_WRITE_MASK1 0x23
#define REG_RAM_WRITE_MASK2 0x24
#define REG_GAMMA_CONTROL_1 0x30
#define REG_GAMMA_CONTROL_2 0x31
#define REG_GAMMA_CONTROL_3 0x32
#define REG_GAMMA_CONTROL_4 0x33
#define REG_GAMMA_CONTROL_5 0x34
#define REG_GAMMA_CONTROL_6 0x35
#define REG_GAMMA_CONTROL_7 0x36
#define REG_GAMMA_CONTROL_8 0x37
#define REG_GAMMA_CONTROL_9 0x38
#define REG_GAMMA_CONTROL_10 0x39
#define REG_GATE_SCAN_CONTROL 0x40
#define REG_VERT_SCROLL_CONTROL 0x41
#define REG_FIRST_SCREEN_DRIVE_POS 0x42
#define REG_SECOND_SCREEN_DRIVE_POS 0x43
#define REG_RAM_ADDR_POS_H 0x44
#define REG_RAM_ADDR_POS_V 0x45
#define REG_OSCILLATOR_CONTROL 0x4F
#define REG_GPIO 0x60
#define REG_OTP_VCM_PROGRAMMING 0x61
#define REG_OTP_VCM_STATUS_ENABLE 0x62
#define REG_OTP_PROGRAMMING_ID_KEY 0x65
/*
* maximum frequency for register access
* (not for the GRAM access)
*/
#define ILITEK_MAX_FREQ_REG 4000000
/*
* Device ID as found in the datasheet (supports 9221 and 9222)
*/
#define ILITEK_DEVICE_ID 0x9220
#define ILITEK_DEVICE_ID_MASK 0xFFF0
/* Last two bits in the START BYTE */
#define START_RS_INDEX 0
#define START_RS_REG 1
#define START_RW_WRITE 0
#define START_RW_READ 1
/**
* START_BYTE(id, rs, rw)
*
* Set the start byte according to the required operation.
* The start byte is defined as:
* ----------------------------------
* | 0 | 1 | 1 | 1 | 0 | ID | RS | RW |
* ----------------------------------
* @id: display's id as set by the manufacturer
* @rs: operation type bit, one of:
* - START_RS_INDEX set the index register
* - START_RS_REG write/read registers/GRAM
* @rw: read/write operation
* - START_RW_WRITE write
* - START_RW_READ read
*/
#define START_BYTE(id, rs, rw) \
(0x70 | (((id) & 0x01) << 2) | (((rs) & 0x01) << 1) | ((rw) & 0x01))
/**
* CHECK_FREQ_REG(spi_device s, spi_transfer x) - Check the frequency
* for the SPI transfer. According to the datasheet, the controller
* accept higher frequency for the GRAM transfer, but it requires
* lower frequency when the registers are read/written.
* The macro sets the frequency in the spi_transfer structure if
* the frequency exceeds the maximum value.
* @s: pointer to an SPI device
* @x: pointer to the read/write buffer pair
*/
#define CHECK_FREQ_REG(s, x) \
do { \
if (s->max_speed_hz > ILITEK_MAX_FREQ_REG) \
((struct spi_transfer *)x)->speed_hz = \
ILITEK_MAX_FREQ_REG; \
} while (0)
#define CMD_BUFSIZE 16
#define POWER_IS_ON(pwr) ((pwr) <= FB_BLANK_NORMAL)
#define set_tx_byte(b) (tx_invert ? ~(b) : b)
/*
* ili922x_id - id as set by manufacturer
*/
static int ili922x_id = 1;
module_param(ili922x_id, int, 0);
static int tx_invert;
module_param(tx_invert, int, 0);
/*
* driver's private structure
*/
struct ili922x {
struct spi_device *spi;
struct lcd_device *ld;
int power;
};
/**
* ili922x_read_status - read status register from display
* @spi: spi device
* @rs: output value
*/
static int ili922x_read_status(struct spi_device *spi, u16 *rs)
{
struct spi_message msg;
struct spi_transfer xfer;
unsigned char tbuf[CMD_BUFSIZE];
unsigned char rbuf[CMD_BUFSIZE];
int ret, i;
memset(&xfer, 0, sizeof(struct spi_transfer));
spi_message_init(&msg);
xfer.tx_buf = tbuf;
xfer.rx_buf = rbuf;
xfer.cs_change = 1;
CHECK_FREQ_REG(spi, &xfer);
tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_INDEX,
START_RW_READ));
/*
* we need 4-byte xfer here due to invalid dummy byte
* received after start byte
*/
for (i = 1; i < 4; i++)
tbuf[i] = set_tx_byte(0); /* dummy */
xfer.bits_per_word = 8;
xfer.len = 4;
spi_message_add_tail(&xfer, &msg);
ret = spi_sync(spi, &msg);
if (ret < 0) {
dev_dbg(&spi->dev, "Error sending SPI message 0x%x", ret);
return ret;
}
*rs = (rbuf[2] << 8) + rbuf[3];
return 0;
}
/**
* ili922x_read - read register from display
* @spi: spi device
* @reg: offset of the register to be read
* @rx: output value
*/
static int ili922x_read(struct spi_device *spi, u8 reg, u16 *rx)
{
struct spi_message msg;
struct spi_transfer xfer_regindex, xfer_regvalue;
unsigned char tbuf[CMD_BUFSIZE];
unsigned char rbuf[CMD_BUFSIZE];
int ret, len = 0, send_bytes;
memset(&xfer_regindex, 0, sizeof(struct spi_transfer));
memset(&xfer_regvalue, 0, sizeof(struct spi_transfer));
spi_message_init(&msg);
xfer_regindex.tx_buf = tbuf;
xfer_regindex.rx_buf = rbuf;
xfer_regindex.cs_change = 1;
CHECK_FREQ_REG(spi, &xfer_regindex);
tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_INDEX,
START_RW_WRITE));
tbuf[1] = set_tx_byte(0);
tbuf[2] = set_tx_byte(reg);
xfer_regindex.bits_per_word = 8;
len = xfer_regindex.len = 3;
spi_message_add_tail(&xfer_regindex, &msg);
send_bytes = len;
tbuf[len++] = set_tx_byte(START_BYTE(ili922x_id, START_RS_REG,
START_RW_READ));
tbuf[len++] = set_tx_byte(0);
tbuf[len] = set_tx_byte(0);
xfer_regvalue.cs_change = 1;
xfer_regvalue.len = 3;
xfer_regvalue.tx_buf = &tbuf[send_bytes];
xfer_regvalue.rx_buf = &rbuf[send_bytes];
CHECK_FREQ_REG(spi, &xfer_regvalue);
spi_message_add_tail(&xfer_regvalue, &msg);
ret = spi_sync(spi, &msg);
if (ret < 0) {
dev_dbg(&spi->dev, "Error sending SPI message 0x%x", ret);
return ret;
}
*rx = (rbuf[1 + send_bytes] << 8) + rbuf[2 + send_bytes];
return 0;
}
/**
* ili922x_write - write a controller register
* @spi: struct spi_device *
* @reg: offset of the register to be written
* @value: value to be written
*/
static int ili922x_write(struct spi_device *spi, u8 reg, u16 value)
{
struct spi_message msg;
struct spi_transfer xfer_regindex, xfer_regvalue;
unsigned char tbuf[CMD_BUFSIZE];
unsigned char rbuf[CMD_BUFSIZE];
int ret;
memset(&xfer_regindex, 0, sizeof(struct spi_transfer));
memset(&xfer_regvalue, 0, sizeof(struct spi_transfer));
spi_message_init(&msg);
xfer_regindex.tx_buf = tbuf;
xfer_regindex.rx_buf = rbuf;
xfer_regindex.cs_change = 1;
CHECK_FREQ_REG(spi, &xfer_regindex);
tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_INDEX,
START_RW_WRITE));
tbuf[1] = set_tx_byte(0);
tbuf[2] = set_tx_byte(reg);
xfer_regindex.bits_per_word = 8;
xfer_regindex.len = 3;
spi_message_add_tail(&xfer_regindex, &msg);
ret = spi_sync(spi, &msg);
spi_message_init(&msg);
tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_REG,
START_RW_WRITE));
tbuf[1] = set_tx_byte((value & 0xFF00) >> 8);
tbuf[2] = set_tx_byte(value & 0x00FF);
xfer_regvalue.cs_change = 1;
xfer_regvalue.len = 3;
xfer_regvalue.tx_buf = tbuf;
xfer_regvalue.rx_buf = rbuf;
CHECK_FREQ_REG(spi, &xfer_regvalue);
spi_message_add_tail(&xfer_regvalue, &msg);
ret = spi_sync(spi, &msg);
if (ret < 0) {
dev_err(&spi->dev, "Error sending SPI message 0x%x", ret);
return ret;
}
return 0;
}
#ifdef DEBUG
/**
* ili922x_reg_dump - dump all registers
*
* @spi: pointer to an SPI device
*/
static void ili922x_reg_dump(struct spi_device *spi)
{
u8 reg;
u16 rx;
dev_dbg(&spi->dev, "ILI922x configuration registers:\n");
for (reg = REG_START_OSCILLATION;
reg <= REG_OTP_PROGRAMMING_ID_KEY; reg++) {
ili922x_read(spi, reg, &rx);
dev_dbg(&spi->dev, "reg @ 0x%02X: 0x%04X\n", reg, rx);
}
}
#else
static inline void ili922x_reg_dump(struct spi_device *spi) {}
#endif
/**
* set_write_to_gram_reg - initialize the display to write the GRAM
* @spi: spi device
*/
static void set_write_to_gram_reg(struct spi_device *spi)
{
struct spi_message msg;
struct spi_transfer xfer;
unsigned char tbuf[CMD_BUFSIZE];
memset(&xfer, 0, sizeof(struct spi_transfer));
spi_message_init(&msg);
xfer.tx_buf = tbuf;
xfer.rx_buf = NULL;
xfer.cs_change = 1;
tbuf[0] = START_BYTE(ili922x_id, START_RS_INDEX, START_RW_WRITE);
tbuf[1] = 0;
tbuf[2] = REG_WRITE_DATA_TO_GRAM;
xfer.bits_per_word = 8;
xfer.len = 3;
spi_message_add_tail(&xfer, &msg);
spi_sync(spi, &msg);
}
/**
* ili922x_poweron - turn the display on
* @spi: spi device
*
* The sequence to turn on the display is taken from
* the datasheet and/or the example code provided by the
* manufacturer.
*/
static int ili922x_poweron(struct spi_device *spi)
{
int ret;
/* Power on */
ret = ili922x_write(spi, REG_POWER_CONTROL_1, 0x0000);
usleep_range(10000, 10500);
ret += ili922x_write(spi, REG_POWER_CONTROL_2, 0x0000);
ret += ili922x_write(spi, REG_POWER_CONTROL_3, 0x0000);
msleep(40);
ret += ili922x_write(spi, REG_POWER_CONTROL_4, 0x0000);
msleep(40);
/* register 0x56 is not documented in the datasheet */
ret += ili922x_write(spi, 0x56, 0x080F);
ret += ili922x_write(spi, REG_POWER_CONTROL_1, 0x4240);
usleep_range(10000, 10500);
ret += ili922x_write(spi, REG_POWER_CONTROL_2, 0x0000);
ret += ili922x_write(spi, REG_POWER_CONTROL_3, 0x0014);
msleep(40);
ret += ili922x_write(spi, REG_POWER_CONTROL_4, 0x1319);
msleep(40);
return ret;
}
/**
* ili922x_poweroff - turn the display off
* @spi: spi device
*/
static int ili922x_poweroff(struct spi_device *spi)
{
int ret;
/* Power off */
ret = ili922x_write(spi, REG_POWER_CONTROL_1, 0x0000);
usleep_range(10000, 10500);
ret += ili922x_write(spi, REG_POWER_CONTROL_2, 0x0000);
ret += ili922x_write(spi, REG_POWER_CONTROL_3, 0x0000);
msleep(40);
ret += ili922x_write(spi, REG_POWER_CONTROL_4, 0x0000);
msleep(40);
return ret;
}
/**
* ili922x_display_init - initialize the display by setting
* the configuration registers
* @spi: spi device
*/
static void ili922x_display_init(struct spi_device *spi)
{
ili922x_write(spi, REG_START_OSCILLATION, 1);
usleep_range(10000, 10500);
ili922x_write(spi, REG_DRIVER_OUTPUT_CONTROL, 0x691B);
ili922x_write(spi, REG_LCD_AC_DRIVEING_CONTROL, 0x0700);
ili922x_write(spi, REG_ENTRY_MODE, 0x1030);
ili922x_write(spi, REG_COMPARE_1, 0x0000);
ili922x_write(spi, REG_COMPARE_2, 0x0000);
ili922x_write(spi, REG_DISPLAY_CONTROL_1, 0x0037);
ili922x_write(spi, REG_DISPLAY_CONTROL_2, 0x0202);
ili922x_write(spi, REG_DISPLAY_CONTROL_3, 0x0000);
ili922x_write(spi, REG_FRAME_CYCLE_CONTROL, 0x0000);
/* Set RGB interface */
ili922x_write(spi, REG_EXT_INTF_CONTROL, 0x0110);
ili922x_poweron(spi);
ili922x_write(spi, REG_GAMMA_CONTROL_1, 0x0302);
ili922x_write(spi, REG_GAMMA_CONTROL_2, 0x0407);
ili922x_write(spi, REG_GAMMA_CONTROL_3, 0x0304);
ili922x_write(spi, REG_GAMMA_CONTROL_4, 0x0203);
ili922x_write(spi, REG_GAMMA_CONTROL_5, 0x0706);
ili922x_write(spi, REG_GAMMA_CONTROL_6, 0x0407);
ili922x_write(spi, REG_GAMMA_CONTROL_7, 0x0706);
ili922x_write(spi, REG_GAMMA_CONTROL_8, 0x0000);
ili922x_write(spi, REG_GAMMA_CONTROL_9, 0x0C06);
ili922x_write(spi, REG_GAMMA_CONTROL_10, 0x0F00);
ili922x_write(spi, REG_RAM_ADDRESS_SET, 0x0000);
ili922x_write(spi, REG_GATE_SCAN_CONTROL, 0x0000);
ili922x_write(spi, REG_VERT_SCROLL_CONTROL, 0x0000);
ili922x_write(spi, REG_FIRST_SCREEN_DRIVE_POS, 0xDB00);
ili922x_write(spi, REG_SECOND_SCREEN_DRIVE_POS, 0xDB00);
ili922x_write(spi, REG_RAM_ADDR_POS_H, 0xAF00);
ili922x_write(spi, REG_RAM_ADDR_POS_V, 0xDB00);
ili922x_reg_dump(spi);
set_write_to_gram_reg(spi);
}
static int ili922x_lcd_power(struct ili922x *lcd, int power)
{
int ret = 0;
if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
ret = ili922x_poweron(lcd->spi);
else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
ret = ili922x_poweroff(lcd->spi);
if (!ret)
lcd->power = power;
return ret;
}
static int ili922x_set_power(struct lcd_device *ld, int power)
{
struct ili922x *ili = lcd_get_data(ld);
return ili922x_lcd_power(ili, power);
}
static int ili922x_get_power(struct lcd_device *ld)
{
struct ili922x *ili = lcd_get_data(ld);
return ili->power;
}
static struct lcd_ops ili922x_ops = {
.get_power = ili922x_get_power,
.set_power = ili922x_set_power,
};
static int ili922x_probe(struct spi_device *spi)
{
struct ili922x *ili;
struct lcd_device *lcd;
int ret;
u16 reg = 0;
ili = devm_kzalloc(&spi->dev, sizeof(*ili), GFP_KERNEL);
if (!ili)
return -ENOMEM;
ili->spi = spi;
spi_set_drvdata(spi, ili);
/* check if the device is connected */
ret = ili922x_read(spi, REG_DRIVER_CODE_READ, &reg);
if (ret || ((reg & ILITEK_DEVICE_ID_MASK) != ILITEK_DEVICE_ID)) {
dev_err(&spi->dev,
"no LCD found: Chip ID 0x%x, ret %d\n",
reg, ret);
return -ENODEV;
}
dev_info(&spi->dev, "ILI%x found, SPI freq %d, mode %d\n",
reg, spi->max_speed_hz, spi->mode);
ret = ili922x_read_status(spi, &reg);
if (ret) {
dev_err(&spi->dev, "reading RS failed...\n");
return ret;
}
dev_dbg(&spi->dev, "status: 0x%x\n", reg);
ili922x_display_init(spi);
ili->power = FB_BLANK_POWERDOWN;
lcd = devm_lcd_device_register(&spi->dev, "ili922xlcd", &spi->dev, ili,
&ili922x_ops);
if (IS_ERR(lcd)) {
dev_err(&spi->dev, "cannot register LCD\n");
return PTR_ERR(lcd);
}
ili->ld = lcd;
spi_set_drvdata(spi, ili);
ili922x_lcd_power(ili, FB_BLANK_UNBLANK);
return 0;
}
static void ili922x_remove(struct spi_device *spi)
{
ili922x_poweroff(spi);
}
static struct spi_driver ili922x_driver = {
.driver = {
.name = "ili922x",
},
.probe = ili922x_probe,
.remove = ili922x_remove,
};
module_spi_driver(ili922x_driver);
MODULE_AUTHOR("Stefano Babic <sbabic@denx.de>");
MODULE_DESCRIPTION("ILI9221/9222 LCD driver");
MODULE_LICENSE("GPL");
MODULE_PARM_DESC(ili922x_id, "set controller identifier (default=1)");
MODULE_PARM_DESC(tx_invert, "invert bytes before sending");
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