On Wed, May 06, 2015 at 09:49:33AM +0200, Heiko Schocher wrote:
> The patch adds LG4573 parallel RGB panel driver with SPI control interface.
> The driver uses drm_panel framework.
This should be obvious by the location of the driver. Can you instead
provide information about the type or resolution of the panel?
> .../devicetree/bindings/panel/lg,lg4573.txt | 42 +++
> drivers/gpu/drm/panel/Kconfig | 8 +
> drivers/gpu/drm/panel/Makefile | 1 +
> drivers/gpu/drm/panel/panel-lg4573.c | 367 +++++++++++++++++++++
> 4 files changed, 418 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/panel/lg,lg4573.txt
> create mode 100644 drivers/gpu/drm/panel/panel-lg4573.c
>
> diff --git a/Documentation/devicetree/bindings/panel/lg,lg4573.txt b/Documentation/devicetree/bindings/panel/lg,lg4573.txt
> new file mode 100644
> index 0000000..55f495d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/panel/lg,lg4573.txt
> @@ -0,0 +1,42 @@
> +LG LG4573 TFT liquid crystal display with SPI control bus
Please capitalize "Liquid Crystal Display".
> +
> +Required properties:
> + - compatible: "lg4573"
This is missing the vendor prefix.
> + - reg: address of the panel on SPI bus
"on the"
> + - display-timings: timings for the connected panel according to [1]
The timings are already implied by the compatible value, so there's no
need to list them in DT.
> +The panel must obey rules for SPI slave device specified in document [2].
> +
> +Optional properties:
> + - power-on-delay: delay after turning regulators on [ms]
How is this a board-specific property? I'd assume that the same panel
always requires the same delay. Perhaps if this is board-specific it
really should be in the corresponding regulator's
regulator-enable-ramp-delay? Then again the binding doesn't describe any
regulators, so what exactly is this delay used for?
> +
> +[1]: Documentation/devicetree/bindings/video/display-timing.txt
> +[2]: Documentation/devicetree/bindings/spi/spi-bus.txt
> +
> +Example:
> +
> + lcd_panel: display@0 {
> + #address-cells = <1>;
> + #size-cells = <1>;
> + compatible = "lg,lg4573";
> + spi-max-frequency = <10000000>;
> + reset-gpios = <&gpio2 11 0>;
This isn't documented above.
> + reg = <0>;
> + power-on-delay = <10>;
> + display-timings {
> + 480x800p57 {
> + native-mode;
> + clock-frequency = <27000027>;
> + hactive = <480>;
> + vactive = <800>;
> + hfront-porch = <10>;
> + hback-porch = <59>;
> + hsync-len = <10>;
> + vback-porch = <15>;
> + vfront-porch = <15>;
> + vsync-len = <15>;
> + hsync-active = <1>;
> + vsync-active = <1>;
> + };
> + };
> + };
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 6d64c7b..29c3407 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -23,6 +23,14 @@ config DRM_PANEL_LD9040
> depends on OF && SPI
> select VIDEOMODE_HELPERS
>
> +config DRM_PANEL_LG4573
> + tristate "LG4573 RGB/SPI panel"
I'd like to get into the habit of prefixing the panels with a vendor
prefix, so this should become something like:
config DRM_PANEL_LG_LG4573
tristate "LG LG4573 RGB/SPI panel"
I have a local patch that converts existing boards, so with this
conversion it'd fit right it.
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 4b2a043..715b95d 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -1,4 +1,5 @@
> obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
> obj-$(CONFIG_DRM_PANEL_LD9040) += panel-ld9040.o
> +obj-$(CONFIG_DRM_PANEL_LG4573) += panel-lg4573.o
Similarly for filenames, this would become: panel-lg-lg4573.c
> obj-$(CONFIG_DRM_PANEL_S6E8AA0) += panel-s6e8aa0.o
> obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o
> diff --git a/drivers/gpu/drm/panel/panel-lg4573.c b/drivers/gpu/drm/panel/panel-lg4573.c
> new file mode 100644
> index 0000000..9d5e5a5
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-lg4573.c
> @@ -0,0 +1,367 @@
> +/*
> + *
> + * Copyright (C) 2015 Heiko Schocher <hs@xxxxxxx>
> + *
> + * from:
> + * drivers/gpu/drm/panel/panel-ld9040.c
> + * ld9040 AMOLED LCD drm_panel driver.
> + *
> + * Copyright (c) 2014 Samsung Electronics Co., Ltd
> + * Derived from drivers/video/backlight/ld9040.c
> + *
> + * Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> + *
> + * 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.
> +*/
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_panel.h>
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +#include <video/mipi_display.h>
> +#include <video/of_videomode.h>
> +#include <video/videomode.h>
> +
> +struct lg4573 {
> + struct device *dev;
> + struct drm_panel panel;
Might be a slight optimization to put panel first in the structure.
> + u32 power_on_delay;
> + struct videomode vm;
> +};
> +
> +static inline struct lg4573 *panel_to_lg4573(struct drm_panel *panel)
> +{
> + return container_of(panel, struct lg4573, panel);
> +}
> +
> +static int lg4573_spi_write_u16(struct lg4573 *ctx, u16 data)
> +{
> + struct spi_device *spi = to_spi_device(ctx->dev);
> + struct spi_transfer xfer = {
> + .len = 2,
No need for this padding. A single space will do.
> + };
> + struct spi_message msg;
> + u16 temp = htons(data);
htons() always has this association to network programming. Perhaps it'd
be better to use cpu_to_be16() here?
> +
> + dev_dbg(ctx->dev, "writing data: %x\n", data);
> + xfer.tx_buf = &temp;
> + spi_message_init(&msg);
> + spi_message_add_tail(&xfer, &msg);
> +
> + return spi_sync(spi, &msg);
> +}
> +
> +static void lg4573_spi_write_u16_array(struct lg4573 *ctx, u16 *buff, int size)
size should be of type size_t. Or in this case it's really a count, so
perhaps rename to count and make it unsigned int.
> +{
> + int idx;
Then this would become unsigned int as well. And a more idiomatic name
would be i.
> +
> + for (idx = 0; idx < size; idx++)
> + lg4573_spi_write_u16(ctx, buff[idx]);
> +}
You completely ignore errors.
> +static void lg4573_display_on(struct lg4573 *ctx)
> +{
> + static u16 sleep_out = 0x7011;
> + static u16 display_on = 0x7029;
These seem to be (0x70 << 8 | MIPI_DCS_EXIT_SLEEP) and (0x70 << 8 |
MIPI_DCS_SET_DISPLAY_ON). Perhaps that 0x70 just means it's followed by
a MIPI DCS command, so I'm thinking perhaps you should add a function
such as lg4573_spi_write_dcs() which only takes the DCS command to avoid
all the repetition.
> +
> + lg4573_spi_write_u16(ctx, sleep_out);
> + msleep(ctx->power_on_delay);
> + lg4573_spi_write_u16(ctx, display_on);
> +}
This also ignores errors. And the post-regulator delay is used here but
I don't see any regulators being powered up. According to the MIPI DCS
specification there needs to be a delay of 5 ms after the EXIT_SLEEP
command and any other command (120 ms if the command is ENTER_SLEEP).
Perhaps that's what you're after here? It would mean that the delay is
not board-specific and hence doesn't belong in DT.
> +static int lg4573_display_off(struct lg4573 *ctx)
> +{
> + static u16 display_off = 0x7028;
> + static u16 sleep_in = 0x7010;
More standard DCS commands. Also unnecessary tab, it should be a single
space instead.
> +
> + lg4573_spi_write_u16(ctx, display_off);
> + msleep(ctx->power_on_delay);
> + lg4573_spi_write_u16(ctx, sleep_in);
> + return 0;
> +}
Also it's weird that this function returns a value. It always returns 0
so there's no point, really. You should perhaps think about propagating
any errors from the SPI write.
> +
> +static void lg4573_display_mode_settings(struct lg4573 *ctx)
> +{
> + static u16 display_mode_settings[] = {
> + 0x703A,
[...]
> + 0x7200,
> + };
Please make use of the 78/80 columns. Also, I don't suppose it'd be
possible to obtain symbolic names for these magic numbers? More of the
same below.
> +static void lg4573_init(struct lg4573 *ctx)
> +{
> + dev_dbg(ctx->dev, "initializing LCD\n");
> +
> + lg4573_display_mode_settings(ctx);
> + lg4573_power_settings(ctx);
> + lg4573_gamma_settings(ctx);
> +}
> +
> +static int lg4573_power_on(struct lg4573 *ctx)
> +{
> + msleep(ctx->power_on_delay);
> + lg4573_display_on(ctx);
> + return 0;
> +}
> +
> +static int lg4573_disable(struct drm_panel *panel)
> +{
> + struct lg4573 *ctx = panel_to_lg4573(panel);
> +
> + return lg4573_display_off(ctx);
> +}
> +
> +static int lg4573_enable(struct drm_panel *panel)
> +{
> + struct lg4573 *ctx = panel_to_lg4573(panel);
> + int ret;
> +
> + lg4573_init(ctx);
> +
> + ret = lg4573_power_on(ctx);
> +
> + return ret;
> +}
I think these should all propagate errors.
> +static int lg4573_get_modes(struct drm_panel *panel)
> +{
> + struct drm_connector *connector = panel->connector;
> + struct lg4573 *ctx = panel_to_lg4573(panel);
> + struct drm_display_mode *mode;
> +
> + mode = drm_mode_create(connector->dev);
> + if (!mode) {
> + DRM_ERROR("failed to create a new display mode\n");
> + return 0;
> + }
> +
> + drm_display_mode_from_videomode(&ctx->vm, mode);
> +
> + mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> + drm_mode_probed_add(connector, mode);
> +
> + return 1;
> +}
You can either use a hard-coded mode or use display timings along with
the helpers to convert the timings to a default mode. No need to parse
the information from DT.
> +static const struct drm_panel_funcs lg4573_drm_funcs = {
> + .disable = lg4573_disable,
> + .enable = lg4573_enable,
> + .get_modes = lg4573_get_modes,
> +};
> +
> +static int lg4573_parse_dt(struct lg4573 *ctx)
> +{
> + struct device *dev = ctx->dev;
> + struct device_node *np = dev->of_node;
> + int ret;
> +
> + ret = of_get_videomode(np, &ctx->vm, 0);
> + if (ret < 0)
> + return ret;
> +
> + of_property_read_u32(np, "power-on-delay", &ctx->power_on_delay);
> +
> + return 0;
> +}
> +
> +static int lg4573_probe(struct spi_device *spi)
> +{
> + struct device *dev = &spi->dev;
> + struct lg4573 *ctx;
> + int ret;
> +
> + ctx = devm_kzalloc(dev, sizeof(struct lg4573), GFP_KERNEL);
> + if (!ctx)
> + return -ENOMEM;
> +
> + spi_set_drvdata(spi, ctx);
> + ctx->dev = dev;
> +
> + ret = lg4573_parse_dt(ctx);
> + if (ret < 0)
> + return ret;
> +
> + spi->bits_per_word = 8;
> + ret = spi_setup(spi);
> + if (ret < 0) {
> + dev_err(dev, "spi setup failed.\n");
You might want to include the error code in the message. Also "SPI".
> +static const struct of_device_id lg4573_of_match[] = {
> + { .compatible = "lg,lg4573" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, lg4573_of_match);
> +
> +static struct spi_driver lg4573_driver = {
> + .probe = lg4573_probe,
> + .remove = lg4573_remove,
> + .driver = {
> + .name = "lg4573",
> + .owner = THIS_MODULE,
> + .of_match_table = lg4573_of_match,
> + },
No need for the padding. It's not consistent anyway.
Thierry
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