Hello Sam, On Fri, Oct 16, 2020 at 10:07:34PM +0200, Sam Ravnborg wrote: > Hi Lubomir. > > On Sat, Sep 26, 2020 at 02:07:19AM +0200, Lubomir Rintel wrote: > > Himax HX8837 is used to drive the LCD panel on OLPC platforms. > > > > It controls the panel backlight and is able to refresh it when the LCD > > controller (and the rest of the plaform) is powered off. > > > > It also converts regular RGB color data from the LCDC so that it looks > > reasonable on the OLPC LCD panel with a monochromatic layer on top of a > > layer that can either reflect light (b/w sunlight readable mode) or light > > pattern of red, green and blue pixels. > > > > At this point, the driver is rather basic. The self-refresh mode is not > > supported. There's no way of independently controlling the color swizzling, > > antialiasing or b/w conversion, but it probably isn't too useful either. > > > > There's another driver for the same hardware on OLPC XO-1.5 and XO-1.75 > > in drivers/staging/olpc_dcon. The display on that hardware doesn't utilize > > DRM, so this driver doesn't replace the other one yet. > > > > Signed-off-by: Lubomir Rintel <lkundrak@xxxxx> > > A little feedback follows. > > Sam > > > > > --- > > Changes since v3: > > - Added this patch, in place of a driver derived from > > drivers/staging/olpc_dcon. Compared to the previous one this > > implements the bare minimum, without the fancy stuff such as > > self-refresh that need more work/thinking. > > > > drivers/gpu/drm/bridge/Kconfig | 13 ++ > > drivers/gpu/drm/bridge/Makefile | 1 + > > drivers/gpu/drm/bridge/himax-hx8837.c | 325 ++++++++++++++++++++++++++ > > 3 files changed, 339 insertions(+) > > create mode 100644 drivers/gpu/drm/bridge/himax-hx8837.c > > > > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig > > index ef91646441b16..6a923dd56c1d5 100644 > > --- a/drivers/gpu/drm/bridge/Kconfig > > +++ b/drivers/gpu/drm/bridge/Kconfig > > @@ -48,6 +48,19 @@ config DRM_DISPLAY_CONNECTOR > > on ARM-based platforms. Saying Y here when this driver is not needed > > will not cause any issue. > > > > +config DRM_HIMAX_HX8837 > > + tristate "HiMax HX8837 OLPC Display Controller" > > + depends on OF > > + depends on OLPC || ARCH_MMP || COMPILE_TEST > > + select DRM_KMS_HELPER > > + select BACKLIGHT_LCD_SUPPORT > > + select BACKLIGHT_CLASS_DEVICE > > + help > > + Enable support for HiMax HX8837 Display Controller as found in the > > + OLPC XO laptops. > > + > > + If your laptop doesn't have green ears, say "N" > > There is a mixture of tabs and spaces for indent - use tabs only (and > tabs + 2 spaces for the help text). > > > > + > > config DRM_LONTIUM_LT9611 > > tristate "Lontium LT9611 DSI/HDMI bridge" > > select SND_SOC_HDMI_CODEC if SND_SOC > > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile > > index 2b3aff104e466..21f72df3260db 100644 > > --- a/drivers/gpu/drm/bridge/Makefile > > +++ b/drivers/gpu/drm/bridge/Makefile > > @@ -2,6 +2,7 @@ > > obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o > > obj-$(CONFIG_DRM_CHRONTEL_CH7033) += chrontel-ch7033.o > > obj-$(CONFIG_DRM_DISPLAY_CONNECTOR) += display-connector.o > > +obj-$(CONFIG_DRM_HIMAX_HX8837) += himax-hx8837.o > Please add in alphabetical order. > > > obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o > > obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o > > obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o > > diff --git a/drivers/gpu/drm/bridge/himax-hx8837.c b/drivers/gpu/drm/bridge/himax-hx8837.c > > new file mode 100644 > > index 0000000000000..1e97fcb8ce505 > > --- /dev/null > > +++ b/drivers/gpu/drm/bridge/himax-hx8837.c > > @@ -0,0 +1,325 @@ > > +// SPDX-License-Identifier: GPL-2.0-or-later > > +/* > > + * HiMax HX8837 Display Controller Driver > > + * > > + * Datasheet: http://wiki.laptop.org/images/0/09/DCON_datasheet_HX8837-A.pdf > > + * > > + * Copyright (C) 2020 Lubomir Rintel > > + */ > > + > > +#include <linux/gpio/consumer.h> > > +#include <linux/module.h> > > +#include <linux/regmap.h> > > + > > +#include <drm/drm_atomic_helper.h> > > +#include <drm/drm_panel.h> > > +#include <drm/drm_bridge.h> > > +#include <drm/drm_of.h> > > +#include <drm/drm_print.h> > > +#include <drm/drm_probe_helper.h> > In blocks are good but please add them in alphabetical order. > > > + > > +#define bridge_to_hx8837_priv(x) \ > > + container_of(x, struct hx8837_priv, bridge) > > + > > +/* DCON registers */ > > +enum { > > + DCON_REG_ID = 0x00, > > + DCON_REG_MODE = 0x01, > > + DCON_REG_HRES = 0x02, > > + DCON_REG_HTOTAL = 0x03, > > + DCON_REG_HSYNC_WIDTH = 0x04, > > + DCON_REG_VRES = 0x05, > > + DCON_REG_VTOTAL = 0x06, > > + DCON_REG_VSYNC_WIDTH = 0x07, > > + DCON_REG_TIMEOUT = 0x08, > > + DCON_REG_SCAN_INT = 0x09, > > + DCON_REG_BRIGHT = 0x0a, > > + DCON_REG_MEM_OPT_A = 0x41, > > + DCON_REG_MEM_OPT_B = 0x42, > > +}; > > + > > +/* DCON_REG_MODE */ > > +enum { > > + MODE_PASSTHRU = BIT(0), > > + MODE_SLEEP = BIT(1), > > + MODE_SLEEP_AUTO = BIT(2), > > + MODE_BL_ENABLE = BIT(3), > > + MODE_BLANK = BIT(4), > > + MODE_CSWIZZLE = BIT(5), > > + MODE_COL_AA = BIT(6), > > + MODE_MONO_LUMA = BIT(7), > > + MODE_SCAN_INT = BIT(8), > > + MODE_CLOCKDIV = BIT(9), > > + MODE_DEBUG = BIT(14), > > + MODE_SELFTEST = BIT(15), > > +}; > > + > > +struct hx8837_priv { > > + struct regmap *regmap; > > + struct gpio_desc *load_gpio; > > + > > + struct drm_bridge *panel_bridge; > > + struct drm_panel *panel; > No need for the panel pointer - use a local variable in the probe > function > > > + struct drm_bridge bridge; > > +}; > > + > > +static int hx8837_bridge_attach(struct drm_bridge *bridge, > > + enum drm_bridge_attach_flags flags) > > +{ > > + struct hx8837_priv *priv = bridge_to_hx8837_priv(bridge); > > + > > + return drm_bridge_attach(bridge->encoder, priv->panel_bridge, > > + bridge, flags); > > +} > > + > > +static enum drm_mode_status hx8837_bridge_mode_valid( > > + struct drm_bridge *bridge, > > + const struct drm_display_info *info, > > + const struct drm_display_mode *mode) > > +{ > > + if (mode->hdisplay > 0xffff) > > + return MODE_BAD_HVALUE; > > + if (mode->htotal > 0xffff) > > + return MODE_BAD_HVALUE; > > + if (mode->hsync_start - mode->hdisplay > 0xff) > > + return MODE_HBLANK_WIDE; > > + if (mode->hsync_end - mode->hsync_start > 0xff) > > + return MODE_HSYNC_WIDE; > > + if (mode->vdisplay > 0xffff) > > + return MODE_BAD_VVALUE; > > + if (mode->vtotal > 0xffff) > > + return MODE_BAD_VVALUE; > > + if (mode->vsync_start - mode->vdisplay > 0xff) > > + return MODE_VBLANK_WIDE; > > + if (mode->vsync_end - mode->vsync_start > 0xff) > > + return MODE_VSYNC_WIDE; > > + > > + return MODE_OK; > > +} > > + > > +static void hx8837_bridge_disable(struct drm_bridge *bridge) > > +{ > > + struct hx8837_priv *priv = bridge_to_hx8837_priv(bridge); > > + int ret; > > + > > + ret = gpiod_direction_output(priv->load_gpio, 0); > > + if (ret) > > + DRM_ERROR("error enabling the dcon load: %d\n", ret); > The driver uses both dev_xxx() and DRM_XXX for logging. > Please stick to one way to do logging - I prefer for bridge drivers > the dev_* variants. > > > + > > + ret = regmap_update_bits(priv->regmap, DCON_REG_MODE, > > + MODE_PASSTHRU | > > + MODE_SLEEP, > > + MODE_PASSTHRU | > > + MODE_SLEEP); > > + if (ret) > > + DRM_ERROR("error disabling the dcon: %d\n", ret); > > +} > > + > > +static void hx8837_bridge_enable(struct drm_bridge *bridge) > > +{ > > + struct hx8837_priv *priv = bridge_to_hx8837_priv(bridge); > > + int ret; > > + > > + ret = regmap_update_bits(priv->regmap, DCON_REG_MODE, > > + MODE_PASSTHRU | > > + MODE_SLEEP | > > + MODE_SLEEP_AUTO | > > + MODE_BLANK | > > + MODE_SCAN_INT | > > + MODE_CLOCKDIV | > > + MODE_DEBUG | > > + MODE_SELFTEST, > > + MODE_PASSTHRU); > > + if (ret) > > + DRM_ERROR("error enabling the dcon: %d\n", ret); > > + > > + ret = gpiod_direction_output(priv->load_gpio, 1); > > + if (ret) > > + DRM_ERROR("error enabling the dcon load: %d\n", ret); > > +} > > + > > +static void hx8837_bridge_mode_set(struct drm_bridge *bridge, > > + const struct drm_display_mode *mode, > > + const struct drm_display_mode *adjusted_mode) > > +{ > > + struct hx8837_priv *priv = bridge_to_hx8837_priv(bridge); > > + > > + regmap_write(priv->regmap, DCON_REG_HRES, mode->hdisplay); > > + regmap_write(priv->regmap, DCON_REG_HTOTAL, mode->htotal); > > + regmap_write(priv->regmap, DCON_REG_HSYNC_WIDTH, > > + (mode->hsync_start - mode->hdisplay) << 8 | > > + (mode->hsync_end - mode->hsync_start)); > > + regmap_write(priv->regmap, DCON_REG_VRES, mode->vdisplay); > > + regmap_write(priv->regmap, DCON_REG_VTOTAL, mode->vtotal); > > + regmap_write(priv->regmap, DCON_REG_VSYNC_WIDTH, > > + (mode->vsync_start - mode->vdisplay) << 8 | > > + (mode->vsync_end - mode->vsync_start)); > > +} > > + > > +static const struct drm_bridge_funcs hx8837_bridge_funcs = { > > + .attach = hx8837_bridge_attach, > > + .mode_valid = hx8837_bridge_mode_valid, > > + .disable = hx8837_bridge_disable, > > + .enable = hx8837_bridge_enable, > > + .mode_set = hx8837_bridge_mode_set, > > +}; > > + > > +static int hx8837_bl_update_status(struct backlight_device *bl) > > +{ > > + struct hx8837_priv *priv = bl_get_data(bl); > > + unsigned int val; > > + int ret; > > + > > + ret = regmap_update_bits(priv->regmap, DCON_REG_BRIGHT, > > + 0x000f, > > + bl->props.brightness); > > Use backlight_get_brightness() to get the brightness. > This will also make sure 0 is returned when backlight is off so the > logic a few lines down is correct. I'm not sure I understand this one. I'm wondering if you could help me out with it before I follow up with v4. Currently I read in the current brightness level in probe() (which prevents struct backlight_properties, below, from being const) and the nthe brightness is entirely in control of the driver via update_status(). What would I need get_brightness() for? We know that whatever the driver set is the current level. It doesn't seem to be called on backlight device registration so it doesn't make the readin in probe() unnecessary either. > > + if (ret) { > > + dev_err(&bl->dev, "error setting the backlight: %d\n", ret); > > + return ret; > > + } > > + > > + if (bl->props.brightness) > > + val = MODE_CSWIZZLE | MODE_COL_AA; > > + else > > + val = MODE_MONO_LUMA; > > + > > + ret = regmap_update_bits(priv->regmap, DCON_REG_MODE, > > + MODE_CSWIZZLE | > > + MODE_COL_AA | > > + MODE_MONO_LUMA, > > + val); > > + if (ret) { > > + dev_err(&bl->dev, "error setting color mode: %d\n", ret); > > + return ret; > > + } > > + > > + return 0; > > +} > > + > > +static const struct backlight_ops hx8837_bl_ops = { > > + .update_status = hx8837_bl_update_status, > > +}; > > + > > +static const struct regmap_config hx8837_regmap_config = { > > + .reg_bits = 8, > > + .val_bits = 16, > > + .max_register = 0x4c, > > + .val_format_endian = REGMAP_ENDIAN_LITTLE, > > +}; > > + > > +static int hx8837_probe(struct i2c_client *client, > > + const struct i2c_device_id *id) > > +{ > > + struct backlight_properties bl_props = { > > + .type = BACKLIGHT_RAW, > > + .max_brightness = 0xf, > > + }; > Make it const > Maybe use a constant for the max value as it is also used as a mask > later. > > > + struct device *dev = &client->dev; > > + struct backlight_device *bl; > > + struct hx8837_priv *priv; > > + unsigned int val; > > + int ret; > > + > > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); > > + if (!priv) > > + return -ENOMEM; > > + > > + dev_set_drvdata(dev, priv); > > + > > + priv->load_gpio = devm_gpiod_get(dev, "load", GPIOD_ASIS); > > + if (IS_ERR(priv->load_gpio)) > > + return PTR_ERR(priv->load_gpio); > > + > > + ret = drm_of_find_panel_or_bridge(dev->of_node, 1, -1, > > + &priv->panel, NULL); > > + if (ret) > > + return ret; > > + > > + if (priv->panel->backlight) { > > + dev_err(dev, "the panel already has a backlight controller\n"); > > + return -ENODEV; > > + } > > + > > + priv->panel_bridge = devm_drm_panel_bridge_add(dev, priv->panel); > > + if (IS_ERR(priv->panel_bridge)) > > + return PTR_ERR(priv->panel_bridge); > > + > > + priv->regmap = devm_regmap_init_i2c(client, &hx8837_regmap_config); > > + if (IS_ERR(priv->regmap)) { > > + dev_err(dev, "regmap init failed\n"); > > + return PTR_ERR(priv->regmap); > > + } > > + > > + ret = regmap_read(priv->regmap, DCON_REG_ID, &val); > > + if (ret < 0) { > > + dev_err(dev, "error reading the model id: %d\n", ret); > > + return ret; > > + } > > + if ((val & 0xff00) != 0xdc00) { > > + dev_err(dev, "the device is not a hx8837\n"); > > + return -ENODEV; > > + } > > + > > + ret = regmap_read(priv->regmap, DCON_REG_BRIGHT, &val); > > + if (ret < 0) { > > + dev_err(&bl->dev, "error getting the backlight: %d\n", ret); > > + return ret; > > + } > > + bl_props.brightness = val & 0xf; > > + > > + bl = devm_backlight_device_register(dev, dev_name(dev), dev, priv, > > + &hx8837_bl_ops, &bl_props); > > + if (IS_ERR(bl)) { > > + dev_err(dev, "failed to register backlight\n"); > > + return PTR_ERR(bl); > > + } > > + > > + priv->panel->backlight = bl; > > + > > + INIT_LIST_HEAD(&priv->bridge.list); > > + priv->bridge.funcs = &hx8837_bridge_funcs; > > + priv->bridge.of_node = dev->of_node; > > + drm_bridge_add(&priv->bridge); > > + > > + dev_info(dev, "HiMax HX8837 Display Controller Driver\n"); > > + return 0; > > +} > > + > > +static int hx8837_remove(struct i2c_client *client) > > +{ > > + struct device *dev = &client->dev; > > + struct hx8837_priv *priv = dev_get_drvdata(dev); > > + > > + drm_bridge_remove(&priv->bridge); > > > + priv->panel->backlight = NULL; > I cannot see why this is needed. > IF this is needed we have a bug in the core stuff we need to fix. > > > + > > + return 0; > > +} > > + > > +static const struct of_device_id hx8837_dt_ids[] = { > > + { .compatible = "himax,hx8837", }, > > + { } > We often see { /* sentinel */ }, > in these cases. > > > +}; > > +MODULE_DEVICE_TABLE(of, hx8837_dt_ids); > > + > > +static const struct i2c_device_id hx8837_ids[] = { > > + { "hx8837", 0 }, > > + { } > Likewise > > > +}; > > +MODULE_DEVICE_TABLE(i2c, hx8837_ids); > > + > > +static struct i2c_driver hx8837_driver = { > > + .probe = hx8837_probe, > > + .remove = hx8837_remove, > > + .driver = { > > + .name = "hx8837", > > + .of_match_table = of_match_ptr(hx8837_dt_ids), > > + }, > > + .id_table = hx8837_ids, > > +}; > > + > > +module_i2c_driver(hx8837_driver); > > + > > +MODULE_AUTHOR("Lubomir Rintel <lkundrak@xxxxx>"); > > +MODULE_DESCRIPTION("HiMax HX8837 Display Controller Driver"); > > +MODULE_LICENSE("GPL"); Thanks Lubo
