Hi,

On 10/10/13 00:08, Marek Belisko wrote:
> For communicating with driver is used gpio bitbanging because TD028 does
> not have a standard compliant SPI interface. It is a 3-wire thing with
> direction reversal.

Isn't that SPI_3WIRE?

> Communication with display is used only during panel enable/disable so it's
> not performance issue.
> 
> Signed-off-by: Marek Belisko <marek@goldelico.com>
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---
>  drivers/video/omap2/displays-new/Kconfig           |   6 +
>  drivers/video/omap2/displays-new/Makefile          |   1 +
>  .../omap2/displays-new/panel-tpo-td028ttec1.c      | 537 +++++++++++++++++++++
>  include/video/omap-panel-data.h                    |  22 +
>  4 files changed, 566 insertions(+)
>  create mode 100644 drivers/video/omap2/displays-new/panel-tpo-td028ttec1.c
> 
> diff --git a/drivers/video/omap2/displays-new/Kconfig b/drivers/video/omap2/displays-new/Kconfig
> index 6c90885..3f86432 100644
> --- a/drivers/video/omap2/displays-new/Kconfig
> +++ b/drivers/video/omap2/displays-new/Kconfig
> @@ -56,6 +56,11 @@ config DISPLAY_PANEL_SHARP_LS037V7DW01
>          help
>            LCD Panel used in TI's SDP3430 and EVM boards
>  
> +config DISPLAY_PANEL_TPO_TD028TTEC1
> +        tristate "TPO TD028TTEC1 LCD Panel"
> +        help
> +          LCD panel used by Openmoko.
> +
>  config DISPLAY_PANEL_TPO_TD043MTEA1
>          tristate "TPO TD043MTEA1 LCD Panel"
>          depends on SPI
> @@ -70,4 +75,5 @@ config DISPLAY_PANEL_NEC_NL8048HL11
>  		This NEC NL8048HL11 panel is TFT LCD used in the
>  		Zoom2/3/3630 sdp boards.
>  
> +

Extra change.

>  endmenu
> diff --git a/drivers/video/omap2/displays-new/Makefile b/drivers/video/omap2/displays-new/Makefile
> index 5aeb11b..0323a8a 100644
> --- a/drivers/video/omap2/displays-new/Makefile
> +++ b/drivers/video/omap2/displays-new/Makefile
> @@ -8,5 +8,6 @@ obj-$(CONFIG_DISPLAY_PANEL_DSI_CM) += panel-dsi-cm.o
>  obj-$(CONFIG_DISPLAY_PANEL_SONY_ACX565AKM) += panel-sony-acx565akm.o
>  obj-$(CONFIG_DISPLAY_PANEL_LGPHILIPS_LB035Q02) += panel-lgphilips-lb035q02.o
>  obj-$(CONFIG_DISPLAY_PANEL_SHARP_LS037V7DW01) += panel-sharp-ls037v7dw01.o
> +obj-$(CONFIG_DISPLAY_PANEL_TPO_TD028TTEC1) += panel-tpo-td028ttec1.o
>  obj-$(CONFIG_DISPLAY_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o
>  obj-$(CONFIG_DISPLAY_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
> diff --git a/drivers/video/omap2/displays-new/panel-tpo-td028ttec1.c b/drivers/video/omap2/displays-new/panel-tpo-td028ttec1.c
> new file mode 100644
> index 0000000..b63586e
> --- /dev/null
> +++ b/drivers/video/omap2/displays-new/panel-tpo-td028ttec1.c
> @@ -0,0 +1,537 @@
> +/*
> + * Toppoly TD028TTEC1 panel support
> + *
> + * Copyright (C) 2008 Nokia Corporation
> + * Author: Tomi Valkeinen <tomi.valkeinen@nokia.com>
> + *
> + * Neo 1973 code (jbt6k74.c):
> + * Copyright (C) 2006-2007 by OpenMoko, Inc.
> + * Author: Harald Welte <laforge@openmoko.org>
> + *
> + * Ported and adapted from Neo 1973 U-Boot by:
> + * H. Nikolaus Schaller <hns@goldelico.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/platform_device.h>
> +#include <linux/gpio.h>
> +#include <video/omapdss.h>
> +#include <video/omap-panel-data.h>
> +
> +struct panel_drv_data {
> +	struct omap_dss_device dssdev;
> +	struct omap_dss_device *in;
> +
> +	int data_lines;
> +
> +	struct omap_video_timings videomode;
> +
> +	int cs_gpio;
> +	int scl_gpio;
> +	int din_gpio;
> +	int dout_gpio;

Three wires, but four gpios? What am I missing here...

> +	u_int16_t tx_buf[4];

Hmm, what's wrong with "u16"?

> +};
> +
> +static struct omap_video_timings td028ttec1_panel_timings = {
> +	.x_res		= 480,
> +	.y_res		= 640,
> +	.pixel_clock	= 22153,
> +	.hfp		= 24,
> +	.hsw		= 8,
> +	.hbp		= 8,
> +	.vfp		= 4,
> +	.vsw		= 2,
> +	.vbp		= 2,
> +
> +	.vsync_level	= OMAPDSS_SIG_ACTIVE_LOW,
> +	.hsync_level	= OMAPDSS_SIG_ACTIVE_LOW,
> +
> +	.data_pclk_edge	= OMAPDSS_DRIVE_SIG_FALLING_EDGE,
> +	.de_level	= OMAPDSS_SIG_ACTIVE_HIGH,
> +	.sync_pclk_edge	= OMAPDSS_DRIVE_SIG_OPPOSITE_EDGES,
> +};
> +
> +#define JBT_COMMAND	0x000
> +#define JBT_DATA	0x100
> +
> +/* 150uS minimum clock cycle, we have two of this plus our other
> + * instructions */
> +
> +#define SPI_DELAY()	udelay(200)

Would usleep_range work here?

See Documentation/timers/timers-howto.txt

> +static int jbt_spi_xfer(struct panel_drv_data *data, int wordnum, int bitlen)

Hmm, if it's not SPI, maybe it shouldn't be called SPI?

> +{
> +	u_int16_t tmpdout = 0;
> +	int   i, j;
> +
> +	gpio_set_value(data->cs_gpio, 0);
> +
> +	for (i = 0; i < wordnum; i++) {
> +		tmpdout = data->tx_buf[i];
> +
> +		for (j = 0; j < bitlen; j++) {
> +			gpio_set_value(data->scl_gpio, 0);
> +			if (tmpdout & (1 << (bitlen-1))) {
> +				gpio_set_value(data->dout_gpio, 1);
> +				if (gpio_get_value(data->din_gpio) == 0)
> +					return 1;
> +			} else {
> +				gpio_set_value(data->dout_gpio, 0);
> +				if (gpio_get_value(data->din_gpio) != 0)
> +					return 1;
> +			}
> +			SPI_DELAY();
> +			gpio_set_value(data->scl_gpio, 1);
> +			SPI_DELAY();
> +			tmpdout <<= 1;
> +		}
> +	}
> +
> +	gpio_set_value(data->cs_gpio, 1);
> +
> +	return 0;
> +}
> +
> +#define JBT_COMMAND	0x000
> +#define JBT_DATA	0x100
> +
> +int jbt_reg_write_nodata(struct panel_drv_data *ddata, u_int8_t reg)

What's wrong with "u8"? Have I missed a memo? =)

> +{
> +	int rc;
> +
> +	ddata->tx_buf[0] = JBT_COMMAND | reg;
> +
> +	rc = jbt_spi_xfer(ddata, 1, 9);
> +	if (rc)
> +		dev_warn(ddata->dssdev.dev, "Failed to write reg: %x\n", reg);
> +
> +	return rc;
> +}
> +
> +int jbt_reg_write(struct panel_drv_data *ddata, u_int8_t reg, u_int8_t data)
> +{
> +	int rc;
> +
> +	ddata->tx_buf[0] = JBT_COMMAND | reg;
> +	ddata->tx_buf[1] = JBT_DATA | data;
> +
> +	rc = jbt_spi_xfer(ddata, 2, 9);
> +	if (rc)
> +		dev_warn(ddata->dssdev.dev, "Failed to write reg: %x\n", reg);
> +
> +	return rc;
> +}
> +
> +int jbt_reg_write16(struct panel_drv_data *ddata, u_int8_t reg, u_int16_t data)
> +{
> +	int rc;
> +
> +	ddata->tx_buf[0] = JBT_COMMAND | reg;
> +	ddata->tx_buf[1] = JBT_DATA | (data >> 8);
> +	ddata->tx_buf[2] = JBT_DATA | (data & 0xff);
> +
> +	rc = jbt_spi_xfer(ddata, 3, 9);
> +	if (rc)
> +		dev_warn(ddata->dssdev.dev, "Failed to write reg: %x\n", reg);
> +
> +	return rc;
> +}
> +
> +enum jbt_register {
> +	JBT_REG_SLEEP_IN		= 0x10,
> +	JBT_REG_SLEEP_OUT		= 0x11,
> +
> +	JBT_REG_DISPLAY_OFF		= 0x28,
> +	JBT_REG_DISPLAY_ON		= 0x29,
> +
> +	JBT_REG_RGB_FORMAT		= 0x3a,
> +	JBT_REG_QUAD_RATE		= 0x3b,
> +
> +	JBT_REG_POWER_ON_OFF		= 0xb0,
> +	JBT_REG_BOOSTER_OP		= 0xb1,
> +	JBT_REG_BOOSTER_MODE		= 0xb2,
> +	JBT_REG_BOOSTER_FREQ		= 0xb3,
> +	JBT_REG_OPAMP_SYSCLK		= 0xb4,
> +	JBT_REG_VSC_VOLTAGE		= 0xb5,
> +	JBT_REG_VCOM_VOLTAGE		= 0xb6,
> +	JBT_REG_EXT_DISPL		= 0xb7,
> +	JBT_REG_OUTPUT_CONTROL		= 0xb8,
> +	JBT_REG_DCCLK_DCEV		= 0xb9,
> +	JBT_REG_DISPLAY_MODE1		= 0xba,
> +	JBT_REG_DISPLAY_MODE2		= 0xbb,
> +	JBT_REG_DISPLAY_MODE		= 0xbc,
> +	JBT_REG_ASW_SLEW		= 0xbd,
> +	JBT_REG_DUMMY_DISPLAY		= 0xbe,
> +	JBT_REG_DRIVE_SYSTEM		= 0xbf,
> +
> +	JBT_REG_SLEEP_OUT_FR_A		= 0xc0,
> +	JBT_REG_SLEEP_OUT_FR_B		= 0xc1,
> +	JBT_REG_SLEEP_OUT_FR_C		= 0xc2,
> +	JBT_REG_SLEEP_IN_LCCNT_D	= 0xc3,
> +	JBT_REG_SLEEP_IN_LCCNT_E	= 0xc4,
> +	JBT_REG_SLEEP_IN_LCCNT_F	= 0xc5,
> +	JBT_REG_SLEEP_IN_LCCNT_G	= 0xc6,
> +
> +	JBT_REG_GAMMA1_FINE_1		= 0xc7,
> +	JBT_REG_GAMMA1_FINE_2		= 0xc8,
> +	JBT_REG_GAMMA1_INCLINATION	= 0xc9,
> +	JBT_REG_GAMMA1_BLUE_OFFSET	= 0xca,
> +
> +	JBT_REG_BLANK_CONTROL		= 0xcf,
> +	JBT_REG_BLANK_TH_TV		= 0xd0,
> +	JBT_REG_CKV_ON_OFF		= 0xd1,
> +	JBT_REG_CKV_1_2			= 0xd2,
> +	JBT_REG_OEV_TIMING		= 0xd3,
> +	JBT_REG_ASW_TIMING_1		= 0xd4,
> +	JBT_REG_ASW_TIMING_2		= 0xd5,
> +
> +	JBT_REG_HCLOCK_VGA		= 0xec,
> +	JBT_REG_HCLOCK_QVGA		= 0xed,
> +};
> +
> +#define to_panel_data(p) container_of(p, struct panel_drv_data, dssdev)
> +
> +static int td028ttec1_panel_connect(struct omap_dss_device *dssdev)
> +{
> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
> +	struct omap_dss_device *in = ddata->in;
> +	int r;
> +
> +	if (omapdss_device_is_connected(dssdev))
> +		return 0;
> +
> +	r = in->ops.dpi->connect(in, dssdev);
> +	if (r)
> +		return r;
> +
> +	return 0;
> +}
> +
> +static void td028ttec1_panel_disconnect(struct omap_dss_device *dssdev)
> +{
> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
> +	struct omap_dss_device *in = ddata->in;
> +
> +	if (!omapdss_device_is_connected(dssdev))
> +		return;
> +
> +	in->ops.dpi->disconnect(in, dssdev);
> +}
> +
> +static int td028ttec1_panel_enable(struct omap_dss_device *dssdev)
> +{
> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
> +	struct omap_dss_device *in = ddata->in;
> +	int r;
> +
> +	if (!omapdss_device_is_connected(dssdev))
> +		return -ENODEV;
> +
> +	if (omapdss_device_is_enabled(dssdev))
> +		return 0;
> +
> +	in->ops.dpi->set_data_lines(in, ddata->data_lines);
> +	in->ops.dpi->set_timings(in, &ddata->videomode);
> +
> +	r = in->ops.dpi->enable(in);
> +	if (r)
> +		return r;
> +
> +	dev_dbg(dssdev->dev, "td028ttec1_panel_enable() - state %d\n",
> +		dssdev->state);
> +
> +	/* three times command zero */
> +	r |= jbt_reg_write_nodata(ddata, 0x00);
> +	udelay(1000);

These are big delays, and I guess the timing is not strict here, so
maybe some sleep variant would be better.

> +	r |= jbt_reg_write_nodata(ddata, 0x00);
> +	udelay(1000);
> +	r |= jbt_reg_write_nodata(ddata, 0x00);
> +	udelay(1000);
> +
> +	/* deep standby out */
> +	r |= jbt_reg_write(ddata, JBT_REG_POWER_ON_OFF, 0x17);
> +
> +	/* RGB I/F on, RAM write off, QVGA through, SIGCON enable */
> +	r |= jbt_reg_write(ddata, JBT_REG_DISPLAY_MODE, 0x80);
> +
> +	/* Quad mode off */
> +	r |= jbt_reg_write(ddata, JBT_REG_QUAD_RATE, 0x00);
> +
> +	/* AVDD on, XVDD on */
> +	r |= jbt_reg_write(ddata, JBT_REG_POWER_ON_OFF, 0x16);
> +
> +	/* Output control */
> +	r |= jbt_reg_write16(ddata, JBT_REG_OUTPUT_CONTROL, 0xfff9);
> +
> +	/* Sleep mode off */
> +	r |= jbt_reg_write_nodata(ddata, JBT_REG_SLEEP_OUT);
> +
> +	/* at this point we have like 50% grey */
> +
> +	/* initialize register set */
> +	r |= jbt_reg_write(ddata, JBT_REG_DISPLAY_MODE1, 0x01);
> +	r |= jbt_reg_write(ddata, JBT_REG_DISPLAY_MODE2, 0x00);
> +	r |= jbt_reg_write(ddata, JBT_REG_RGB_FORMAT, 0x60);
> +	r |= jbt_reg_write(ddata, JBT_REG_DRIVE_SYSTEM, 0x10);
> +	r |= jbt_reg_write(ddata, JBT_REG_BOOSTER_OP, 0x56);
> +	r |= jbt_reg_write(ddata, JBT_REG_BOOSTER_MODE, 0x33);
> +	r |= jbt_reg_write(ddata, JBT_REG_BOOSTER_FREQ, 0x11);
> +	r |= jbt_reg_write(ddata, JBT_REG_BOOSTER_FREQ, 0x11);
> +	r |= jbt_reg_write(ddata, JBT_REG_OPAMP_SYSCLK, 0x02);
> +	r |= jbt_reg_write(ddata, JBT_REG_VSC_VOLTAGE, 0x2b);
> +	r |= jbt_reg_write(ddata, JBT_REG_VCOM_VOLTAGE, 0x40);
> +	r |= jbt_reg_write(ddata, JBT_REG_EXT_DISPL, 0x03);
> +	r |= jbt_reg_write(ddata, JBT_REG_DCCLK_DCEV, 0x04);
> +	/*
> +	 * default of 0x02 in JBT_REG_ASW_SLEW responsible for 72Hz requirement
> +	 * to avoid red / blue flicker
> +	 */
> +	r |= jbt_reg_write(ddata, JBT_REG_ASW_SLEW, 0x04);
> +	r |= jbt_reg_write(ddata, JBT_REG_DUMMY_DISPLAY, 0x00);
> +
> +	r |= jbt_reg_write(ddata, JBT_REG_SLEEP_OUT_FR_A, 0x11);
> +	r |= jbt_reg_write(ddata, JBT_REG_SLEEP_OUT_FR_B, 0x11);
> +	r |= jbt_reg_write(ddata, JBT_REG_SLEEP_OUT_FR_C, 0x11);
> +	r |= jbt_reg_write16(ddata, JBT_REG_SLEEP_IN_LCCNT_D, 0x2040);
> +	r |= jbt_reg_write16(ddata, JBT_REG_SLEEP_IN_LCCNT_E, 0x60c0);
> +	r |= jbt_reg_write16(ddata, JBT_REG_SLEEP_IN_LCCNT_F, 0x1020);
> +	r |= jbt_reg_write16(ddata, JBT_REG_SLEEP_IN_LCCNT_G, 0x60c0);
> +
> +	r |= jbt_reg_write16(ddata, JBT_REG_GAMMA1_FINE_1, 0x5533);
> +	r |= jbt_reg_write(ddata, JBT_REG_GAMMA1_FINE_2, 0x00);
> +	r |= jbt_reg_write(ddata, JBT_REG_GAMMA1_INCLINATION, 0x00);
> +	r |= jbt_reg_write(ddata, JBT_REG_GAMMA1_BLUE_OFFSET, 0x00);
> +	r |= jbt_reg_write(ddata, JBT_REG_GAMMA1_BLUE_OFFSET, 0x00);
> +
> +	r |= jbt_reg_write16(ddata, JBT_REG_HCLOCK_VGA, 0x1f0);
> +	r |= jbt_reg_write(ddata, JBT_REG_BLANK_CONTROL, 0x02);
> +	r |= jbt_reg_write16(ddata, JBT_REG_BLANK_TH_TV, 0x0804);
> +	r |= jbt_reg_write16(ddata, JBT_REG_BLANK_TH_TV, 0x0804);
> +
> +	r |= jbt_reg_write(ddata, JBT_REG_CKV_ON_OFF, 0x01);
> +	r |= jbt_reg_write16(ddata, JBT_REG_CKV_1_2, 0x0000);
> +
> +	r |= jbt_reg_write16(ddata, JBT_REG_OEV_TIMING, 0x0d0e);
> +	r |= jbt_reg_write16(ddata, JBT_REG_ASW_TIMING_1, 0x11a4);
> +	r |= jbt_reg_write(ddata, JBT_REG_ASW_TIMING_2, 0x0e);
> +
> +	r |= jbt_reg_write_nodata(ddata, JBT_REG_DISPLAY_ON);
> +
> +	dssdev->state = OMAP_DSS_DISPLAY_ACTIVE;
> +
> +	return r;
> +}
> +
> +static void td028ttec1_panel_disable(struct omap_dss_device *dssdev)
> +{
> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
> +	struct omap_dss_device *in = ddata->in;
> +
> +	if (!omapdss_device_is_enabled(dssdev))
> +		return;
> +
> +	dev_dbg(dssdev->dev, "td028ttec1_panel_disable()\n");
> +
> +	in->ops.dpi->disable(in);
> +
> +	jbt_reg_write_nodata(ddata, JBT_REG_DISPLAY_OFF);
> +	jbt_reg_write16(ddata, JBT_REG_OUTPUT_CONTROL, 0x8002);
> +	jbt_reg_write_nodata(ddata, JBT_REG_SLEEP_IN);
> +	jbt_reg_write(ddata, JBT_REG_POWER_ON_OFF, 0x00);
> +
> +	dssdev->state = OMAP_DSS_DISPLAY_DISABLED;
> +}
> +
> +static void td028ttec1_panel_set_timings(struct omap_dss_device *dssdev,
> +		struct omap_video_timings *timings)
> +{
> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
> +	struct omap_dss_device *in = ddata->in;
> +
> +	ddata->videomode = *timings;
> +	dssdev->panel.timings = *timings;
> +
> +	in->ops.dpi->set_timings(in, timings);
> +}
> +
> +static void td028ttec1_panel_get_timings(struct omap_dss_device *dssdev,
> +		struct omap_video_timings *timings)
> +{
> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
> +
> +	*timings = ddata->videomode;
> +}
> +
> +static int td028ttec1_panel_check_timings(struct omap_dss_device *dssdev,
> +		struct omap_video_timings *timings)
> +{
> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
> +	struct omap_dss_device *in = ddata->in;
> +
> +	return in->ops.dpi->check_timings(in, timings);
> +}
> +
> +static struct omap_dss_driver td028ttec1_ops = {
> +	.connect	= td028ttec1_panel_connect,
> +	.disconnect	= td028ttec1_panel_disconnect,
> +
> +	.enable		= td028ttec1_panel_enable,
> +	.disable	= td028ttec1_panel_disable,
> +
> +	.set_timings	= td028ttec1_panel_set_timings,
> +	.get_timings	= td028ttec1_panel_get_timings,
> +	.check_timings	= td028ttec1_panel_check_timings,
> +};
> +
> +static int td028ttec1_panel_probe_pdata(struct platform_device *pdev)
> +{
> +	const struct panel_tpo_td028tec1_platform_data *pdata;
> +	struct panel_drv_data *ddata = platform_get_drvdata(pdev);
> +	struct omap_dss_device *dssdev, *in;
> +
> +	pdata = dev_get_platdata(&pdev->dev);
> +
> +	in = omap_dss_find_output(pdata->source);
> +	if (in == NULL) {
> +		dev_err(&pdev->dev, "failed to find video source '%s'\n",
> +				pdata->source);
> +		return -EPROBE_DEFER;
> +	}
> +
> +	ddata->in = in;
> +
> +	ddata->data_lines = pdata->data_lines;
> +
> +	dssdev = &ddata->dssdev;
> +	dssdev->name = pdata->name;
> +
> +	ddata->cs_gpio = pdata->cs_gpio;
> +	ddata->scl_gpio = pdata->scl_gpio;
> +	ddata->din_gpio = pdata->din_gpio;
> +	ddata->dout_gpio = pdata->dout_gpio;
> +
> +	return 0;
> +}
> +
> +static int td028ttec1_panel_probe(struct platform_device *pdev)
> +{
> +	struct panel_drv_data *ddata;
> +	struct omap_dss_device *dssdev;
> +	int r;
> +
> +	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
> +	if (ddata == NULL)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, ddata);
> +
> +	if (dev_get_platdata(&pdev->dev)) {
> +		r = td028ttec1_panel_probe_pdata(pdev);
> +		if (r)
> +			return r;
> +	} else {
> +		return -ENODEV;
> +	}
> +
> +	if (gpio_is_valid(ddata->cs_gpio)) {
> +		r = devm_gpio_request_one(&pdev->dev, ddata->cs_gpio,
> +				GPIOF_OUT_INIT_HIGH, "lcd cs");
> +		if (r)
> +			goto err_gpio;
> +	}
> +
> +	if (gpio_is_valid(ddata->scl_gpio)) {
> +		r = devm_gpio_request_one(&pdev->dev, ddata->scl_gpio,
> +				GPIOF_OUT_INIT_HIGH, "lcd scl");
> +		if (r)
> +			goto err_gpio;
> +	}
> +
> +	if (gpio_is_valid(ddata->dout_gpio)) {
> +		r = devm_gpio_request_one(&pdev->dev, ddata->dout_gpio,
> +				GPIOF_OUT_INIT_LOW, "lcd dout");
> +		if (r)
> +			goto err_gpio;
> +	}
> +
> +	if (gpio_is_valid(ddata->din_gpio)) {
> +		r = devm_gpio_request_one(&pdev->dev, ddata->din_gpio,
> +				GPIOF_IN, "lcd din");
> +		if (r)
> +			goto err_gpio;
> +	}
> +
> +	/* according to data sheet: wait 50ms (Tpos of LCM). However, 50ms
> +	 * seems unreliable with later LCM batches, increasing to 90ms */
> +	mdelay(90);

What is this delay for? Usually sleeps/delays should be between two "HW
actions". Here there's nothing below this line that would count as such
an action.

> +	ddata->videomode = td028ttec1_panel_timings;
> +
> +	dssdev = &ddata->dssdev;
> +	dssdev->dev = &pdev->dev;
> +	dssdev->driver = &td028ttec1_ops;
> +	dssdev->type = OMAP_DISPLAY_TYPE_DPI;
> +	dssdev->owner = THIS_MODULE;
> +	dssdev->panel.timings = ddata->videomode;
> +	dssdev->phy.dpi.data_lines = ddata->data_lines;
> +
> +	r = omapdss_register_display(dssdev);
> +	if (r) {
> +		dev_err(&pdev->dev, "Failed to register panel\n");
> +		goto err_reg;
> +	}
> +
> +	return 0;
> +
> +err_reg:
> +err_gpio:
> +	omap_dss_put_device(ddata->in);
> +	return r;
> +}
> +

 Tomi