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linux/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c
Colin Ian King b0baf85bb2 drm/panel: tpo-td043mtea1: remove redundant assignment 
Variable val is initialized to a value in a for-loop that is
never read and hence it is redundant. Remove it.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190817122124.29650-1-colin.king@canonical.com
2019-08-17 16:53:55 +02:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* Toppoly TD043MTEA1 Panel Driver
*
* Copyright (C) 2019 Texas Instruments Incorporated
*
* Based on the omapdrm-specific panel-tpo-td043mtea1 driver
*
* Author: Gražvydas Ignotas <notasas@gmail.com>
*/
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <drm/drm_connector.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>
#define TPO_R02_MODE(x) ((x) & 7)
#define TPO_R02_MODE_800x480 7
#define TPO_R02_NCLK_RISING BIT(3)
#define TPO_R02_HSYNC_HIGH BIT(4)
#define TPO_R02_VSYNC_HIGH BIT(5)
#define TPO_R03_NSTANDBY BIT(0)
#define TPO_R03_EN_CP_CLK BIT(1)
#define TPO_R03_EN_VGL_PUMP BIT(2)
#define TPO_R03_EN_PWM BIT(3)
#define TPO_R03_DRIVING_CAP_100 BIT(4)
#define TPO_R03_EN_PRE_CHARGE BIT(6)
#define TPO_R03_SOFTWARE_CTL BIT(7)
#define TPO_R04_NFLIP_H BIT(0)
#define TPO_R04_NFLIP_V BIT(1)
#define TPO_R04_CP_CLK_FREQ_1H BIT(2)
#define TPO_R04_VGL_FREQ_1H BIT(4)
#define TPO_R03_VAL_NORMAL \
(TPO_R03_NSTANDBY | TPO_R03_EN_CP_CLK | TPO_R03_EN_VGL_PUMP | \
TPO_R03_EN_PWM | TPO_R03_DRIVING_CAP_100 | TPO_R03_EN_PRE_CHARGE | \
TPO_R03_SOFTWARE_CTL)
#define TPO_R03_VAL_STANDBY \
(TPO_R03_DRIVING_CAP_100 | TPO_R03_EN_PRE_CHARGE | \
TPO_R03_SOFTWARE_CTL)
static const u16 td043mtea1_def_gamma[12] = {
105, 315, 381, 431, 490, 537, 579, 686, 780, 837, 880, 1023
};
struct td043mtea1_panel {
struct drm_panel panel;
struct spi_device *spi;
struct regulator *vcc_reg;
struct gpio_desc *reset_gpio;
unsigned int mode;
u16 gamma[12];
bool vmirror;
bool powered_on;
bool spi_suspended;
bool power_on_resume;
};
#define to_td043mtea1_device(p) container_of(p, struct td043mtea1_panel, panel)
/* -----------------------------------------------------------------------------
* Hardware Access
*/
static int td043mtea1_write(struct td043mtea1_panel *lcd, u8 addr, u8 value)
{
struct spi_message msg;
struct spi_transfer xfer;
u16 data;
int ret;
spi_message_init(&msg);
memset(&xfer, 0, sizeof(xfer));
data = ((u16)addr << 10) | (1 << 8) | value;
xfer.tx_buf = &data;
xfer.bits_per_word = 16;
xfer.len = 2;
spi_message_add_tail(&xfer, &msg);
ret = spi_sync(lcd->spi, &msg);
if (ret < 0)
dev_warn(&lcd->spi->dev, "failed to write to LCD reg (%d)\n",
ret);
return ret;
}
static void td043mtea1_write_gamma(struct td043mtea1_panel *lcd)
{
const u16 *gamma = lcd->gamma;
unsigned int i;
u8 val;
/* gamma bits [9:8] */
for (val = i = 0; i < 4; i++)
val |= (gamma[i] & 0x300) >> ((i + 1) * 2);
td043mtea1_write(lcd, 0x11, val);
for (val = i = 0; i < 4; i++)
val |= (gamma[i + 4] & 0x300) >> ((i + 1) * 2);
td043mtea1_write(lcd, 0x12, val);
for (val = i = 0; i < 4; i++)
val |= (gamma[i + 8] & 0x300) >> ((i + 1) * 2);
td043mtea1_write(lcd, 0x13, val);
/* gamma bits [7:0] */
for (i = 0; i < 12; i++)
td043mtea1_write(lcd, 0x14 + i, gamma[i] & 0xff);
}
static int td043mtea1_write_mirror(struct td043mtea1_panel *lcd)
{
u8 reg4 = TPO_R04_NFLIP_H | TPO_R04_NFLIP_V |
TPO_R04_CP_CLK_FREQ_1H | TPO_R04_VGL_FREQ_1H;
if (lcd->vmirror)
reg4 &= ~TPO_R04_NFLIP_V;
return td043mtea1_write(lcd, 4, reg4);
}
static int td043mtea1_power_on(struct td043mtea1_panel *lcd)
{
int ret;
if (lcd->powered_on)
return 0;
ret = regulator_enable(lcd->vcc_reg);
if (ret < 0)
return ret;
/* Wait for the panel to stabilize. */
msleep(160);
gpiod_set_value(lcd->reset_gpio, 0);
td043mtea1_write(lcd, 2, TPO_R02_MODE(lcd->mode) | TPO_R02_NCLK_RISING);
td043mtea1_write(lcd, 3, TPO_R03_VAL_NORMAL);
td043mtea1_write(lcd, 0x20, 0xf0);
td043mtea1_write(lcd, 0x21, 0xf0);
td043mtea1_write_mirror(lcd);
td043mtea1_write_gamma(lcd);
lcd->powered_on = true;
return 0;
}
static void td043mtea1_power_off(struct td043mtea1_panel *lcd)
{
if (!lcd->powered_on)
return;
td043mtea1_write(lcd, 3, TPO_R03_VAL_STANDBY | TPO_R03_EN_PWM);
gpiod_set_value(lcd->reset_gpio, 1);
/* wait for at least 2 vsyncs before cutting off power */
msleep(50);
td043mtea1_write(lcd, 3, TPO_R03_VAL_STANDBY);
regulator_disable(lcd->vcc_reg);
lcd->powered_on = false;
}
/* -----------------------------------------------------------------------------
* sysfs
*/
static ssize_t vmirror_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", lcd->vmirror);
}
static ssize_t vmirror_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
int val;
int ret;
ret = kstrtoint(buf, 0, &val);
if (ret < 0)
return ret;
lcd->vmirror = !!val;
ret = td043mtea1_write_mirror(lcd);
if (ret < 0)
return ret;
return count;
}
static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE, "%d\n", lcd->mode);
}
static ssize_t mode_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
long val;
int ret;
ret = kstrtol(buf, 0, &val);
if (ret != 0 || val & ~7)
return -EINVAL;
lcd->mode = val;
val |= TPO_R02_NCLK_RISING;
td043mtea1_write(lcd, 2, val);
return count;
}
static ssize_t gamma_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
ssize_t len = 0;
unsigned int i;
int ret;
for (i = 0; i < ARRAY_SIZE(lcd->gamma); i++) {
ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
lcd->gamma[i]);
if (ret < 0)
return ret;
len += ret;
}
buf[len - 1] = '\n';
return len;
}
static ssize_t gamma_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
unsigned int g[12];
unsigned int i;
int ret;
ret = sscanf(buf, "%u %u %u %u %u %u %u %u %u %u %u %u",
&g[0], &g[1], &g[2], &g[3], &g[4], &g[5],
&g[6], &g[7], &g[8], &g[9], &g[10], &g[11]);
if (ret != 12)
return -EINVAL;
for (i = 0; i < 12; i++)
lcd->gamma[i] = g[i];
td043mtea1_write_gamma(lcd);
return count;
}
static DEVICE_ATTR_RW(vmirror);
static DEVICE_ATTR_RW(mode);
static DEVICE_ATTR_RW(gamma);
static struct attribute *td043mtea1_attrs[] = {
&dev_attr_vmirror.attr,
&dev_attr_mode.attr,
&dev_attr_gamma.attr,
NULL,
};
static const struct attribute_group td043mtea1_attr_group = {
.attrs = td043mtea1_attrs,
};
/* -----------------------------------------------------------------------------
* Panel Operations
*/
static int td043mtea1_unprepare(struct drm_panel *panel)
{
struct td043mtea1_panel *lcd = to_td043mtea1_device(panel);
if (!lcd->spi_suspended)
td043mtea1_power_off(lcd);
return 0;
}
static int td043mtea1_prepare(struct drm_panel *panel)
{
struct td043mtea1_panel *lcd = to_td043mtea1_device(panel);
int ret;
/*
* If we are resuming from system suspend, SPI might not be enabled
* yet, so we'll program the LCD from SPI PM resume callback.
*/
if (lcd->spi_suspended)
return 0;
ret = td043mtea1_power_on(lcd);
if (ret) {
dev_err(&lcd->spi->dev, "%s: power on failed (%d)\n",
__func__, ret);
return ret;
}
return 0;
}
static const struct drm_display_mode td043mtea1_mode = {
.clock = 36000,
.hdisplay = 800,
.hsync_start = 800 + 68,
.hsync_end = 800 + 68 + 1,
.htotal = 800 + 68 + 1 + 214,
.vdisplay = 480,
.vsync_start = 480 + 39,
.vsync_end = 480 + 39 + 1,
.vtotal = 480 + 39 + 1 + 34,
.vrefresh = 60,
.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
.width_mm = 94,
.height_mm = 56,
};
static int td043mtea1_get_modes(struct drm_panel *panel)
{
struct drm_connector *connector = panel->connector;
struct drm_display_mode *mode;
mode = drm_mode_duplicate(panel->drm, &td043mtea1_mode);
if (!mode)
return -ENOMEM;
drm_mode_set_name(mode);
drm_mode_probed_add(connector, mode);
connector->display_info.width_mm = td043mtea1_mode.width_mm;
connector->display_info.height_mm = td043mtea1_mode.height_mm;
/*
* FIXME: According to the datasheet sync signals are sampled on the
* rising edge of the clock, but the code running on the OMAP3 Pandora
* indicates sampling on the falling edge. This should be tested on a
* real device.
*/
connector->display_info.bus_flags = DRM_BUS_FLAG_DE_HIGH
| DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE
| DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE;
return 1;
}
static const struct drm_panel_funcs td043mtea1_funcs = {
.unprepare = td043mtea1_unprepare,
.prepare = td043mtea1_prepare,
.get_modes = td043mtea1_get_modes,
};
/* -----------------------------------------------------------------------------
* Power Management, Probe and Remove
*/
static int __maybe_unused td043mtea1_suspend(struct device *dev)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
if (lcd->powered_on) {
td043mtea1_power_off(lcd);
lcd->powered_on = true;
}
lcd->spi_suspended = true;
return 0;
}
static int __maybe_unused td043mtea1_resume(struct device *dev)
{
struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
int ret;
lcd->spi_suspended = false;
if (lcd->powered_on) {
lcd->powered_on = false;
ret = td043mtea1_power_on(lcd);
if (ret)
return ret;
}
return 0;
}
static SIMPLE_DEV_PM_OPS(td043mtea1_pm_ops, td043mtea1_suspend,
td043mtea1_resume);
static int td043mtea1_probe(struct spi_device *spi)
{
struct td043mtea1_panel *lcd;
int ret;
lcd = devm_kzalloc(&spi->dev, sizeof(*lcd), GFP_KERNEL);
if (lcd == NULL)
return -ENOMEM;
spi_set_drvdata(spi, lcd);
lcd->spi = spi;
lcd->mode = TPO_R02_MODE_800x480;
memcpy(lcd->gamma, td043mtea1_def_gamma, sizeof(lcd->gamma));
lcd->vcc_reg = devm_regulator_get(&spi->dev, "vcc");
if (IS_ERR(lcd->vcc_reg)) {
dev_err(&spi->dev, "failed to get VCC regulator\n");
return PTR_ERR(lcd->vcc_reg);
}
lcd->reset_gpio = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(lcd->reset_gpio)) {
dev_err(&spi->dev, "failed to get reset GPIO\n");
return PTR_ERR(lcd->reset_gpio);
}
spi->bits_per_word = 16;
spi->mode = SPI_MODE_0;
ret = spi_setup(spi);
if (ret < 0) {
dev_err(&spi->dev, "failed to setup SPI: %d\n", ret);
return ret;
}
ret = sysfs_create_group(&spi->dev.kobj, &td043mtea1_attr_group);
if (ret < 0) {
dev_err(&spi->dev, "failed to create sysfs files\n");
return ret;
}
drm_panel_init(&lcd->panel);
lcd->panel.dev = &lcd->spi->dev;
lcd->panel.funcs = &td043mtea1_funcs;
ret = drm_panel_add(&lcd->panel);
if (ret < 0) {
sysfs_remove_group(&spi->dev.kobj, &td043mtea1_attr_group);
return ret;
}
return 0;
}
static int td043mtea1_remove(struct spi_device *spi)
{
struct td043mtea1_panel *lcd = spi_get_drvdata(spi);
drm_panel_remove(&lcd->panel);
drm_panel_disable(&lcd->panel);
drm_panel_unprepare(&lcd->panel);
sysfs_remove_group(&spi->dev.kobj, &td043mtea1_attr_group);
return 0;
}
static const struct of_device_id td043mtea1_of_match[] = {
{ .compatible = "tpo,td043mtea1", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, td043mtea1_of_match);
static struct spi_driver td043mtea1_driver = {
.probe = td043mtea1_probe,
.remove = td043mtea1_remove,
.driver = {
.name = "panel-tpo-td043mtea1",
.pm = &td043mtea1_pm_ops,
.of_match_table = td043mtea1_of_match,
},
};
module_spi_driver(td043mtea1_driver);
MODULE_ALIAS("spi:tpo,td043mtea1");
MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>");
MODULE_DESCRIPTION("TPO TD043MTEA1 Panel Driver");
MODULE_LICENSE("GPL");
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