From: Marian Cichy Date: Mon, 6 Mar 2023 11:52:49 +0000 (+0100) Subject: drm/imx/lcdc: Implement DRM driver for imx25 X-Git-Tag: v6.6.17~3937^2~23^2~656 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c87e859cdeb5d106cb861326e3135c606d61f88d;p=platform%2Fkernel%2Flinux-rpi.git drm/imx/lcdc: Implement DRM driver for imx25 Add support for the LCD Controller found on i.MX21 and i.MX25. It targets to be a drop in replacement for the imx-fb driver. [ukl: Rebase to a newer kernel version, various smaller fixes and improvements] Signed-off-by: Marian Cichy Reviewed-by: Philipp Zabel Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20230306115249.2223042-2-u.kleine-koenig@pengutronix.de Signed-off-by: Philipp Zabel Link: https://patchwork.freedesktop.org/patch/msgid/20230306115249.2223042-3-u.kleine-koenig@pengutronix.de --- diff --git a/drivers/gpu/drm/imx/Kconfig b/drivers/gpu/drm/imx/Kconfig index e574992..03535a1 100644 --- a/drivers/gpu/drm/imx/Kconfig +++ b/drivers/gpu/drm/imx/Kconfig @@ -2,3 +2,4 @@ source "drivers/gpu/drm/imx/dcss/Kconfig" source "drivers/gpu/drm/imx/ipuv3/Kconfig" +source "drivers/gpu/drm/imx/lcdc/Kconfig" diff --git a/drivers/gpu/drm/imx/Makefile b/drivers/gpu/drm/imx/Makefile index 9096228..86f38e7 100644 --- a/drivers/gpu/drm/imx/Makefile +++ b/drivers/gpu/drm/imx/Makefile @@ -2,3 +2,4 @@ obj-$(CONFIG_DRM_IMX_DCSS) += dcss/ obj-$(CONFIG_DRM_IMX) += ipuv3/ +obj-$(CONFIG_DRM_IMX_LCDC) += lcdc/ diff --git a/drivers/gpu/drm/imx/lcdc/Kconfig b/drivers/gpu/drm/imx/lcdc/Kconfig new file mode 100644 index 0000000..7e57922 --- /dev/null +++ b/drivers/gpu/drm/imx/lcdc/Kconfig @@ -0,0 +1,7 @@ +config DRM_IMX_LCDC + tristate "Freescale i.MX LCDC displays" + depends on DRM && (ARCH_MXC || COMPILE_TEST) + select DRM_GEM_DMA_HELPER + select DRM_KMS_HELPER + help + Found on i.MX1, i.MX21, i.MX25 and i.MX27. diff --git a/drivers/gpu/drm/imx/lcdc/Makefile b/drivers/gpu/drm/imx/lcdc/Makefile new file mode 100644 index 0000000..e84daa4 --- /dev/null +++ b/drivers/gpu/drm/imx/lcdc/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_DRM_IMX_LCDC) += imx-lcdc.o diff --git a/drivers/gpu/drm/imx/lcdc/imx-lcdc.c b/drivers/gpu/drm/imx/lcdc/imx-lcdc.c new file mode 100644 index 0000000..24bc7b3 --- /dev/null +++ b/drivers/gpu/drm/imx/lcdc/imx-lcdc.c @@ -0,0 +1,545 @@ +// SPDX-License-Identifier: GPL-2.0-only +// SPDX-FileCopyrightText: 2020 Marian Cichy + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define IMX21LCDC_LSSAR 0x0000 /* LCDC Screen Start Address Register */ +#define IMX21LCDC_LSR 0x0004 /* LCDC Size Register */ +#define IMX21LCDC_LVPWR 0x0008 /* LCDC Virtual Page Width Register */ +#define IMX21LCDC_LCPR 0x000C /* LCDC Cursor Position Register */ +#define IMX21LCDC_LCWHB 0x0010 /* LCDC Cursor Width Height and Blink Register*/ +#define IMX21LCDC_LCCMR 0x0014 /* LCDC Color Cursor Mapping Register */ +#define IMX21LCDC_LPCR 0x0018 /* LCDC Panel Configuration Register */ +#define IMX21LCDC_LHCR 0x001C /* LCDC Horizontal Configuration Register */ +#define IMX21LCDC_LVCR 0x0020 /* LCDC Vertical Configuration Register */ +#define IMX21LCDC_LPOR 0x0024 /* LCDC Panning Offset Register */ +#define IMX21LCDC_LSCR 0x0028 /* LCDC Sharp Configuration Register */ +#define IMX21LCDC_LPCCR 0x002C /* LCDC PWM Contrast Control Register */ +#define IMX21LCDC_LDCR 0x0030 /* LCDC DMA Control Register */ +#define IMX21LCDC_LRMCR 0x0034 /* LCDC Refresh Mode Control Register */ +#define IMX21LCDC_LICR 0x0038 /* LCDC Interrupt Configuration Register */ +#define IMX21LCDC_LIER 0x003C /* LCDC Interrupt Enable Register */ +#define IMX21LCDC_LISR 0x0040 /* LCDC Interrupt Status Register */ +#define IMX21LCDC_LGWSAR 0x0050 /* LCDC Graphic Window Start Address Register */ +#define IMX21LCDC_LGWSR 0x0054 /* LCDC Graph Window Size Register */ +#define IMX21LCDC_LGWVPWR 0x0058 /* LCDC Graphic Window Virtual Page Width Register */ +#define IMX21LCDC_LGWPOR 0x005C /* LCDC Graphic Window Panning Offset Register */ +#define IMX21LCDC_LGWPR 0x0060 /* LCDC Graphic Window Position Register */ +#define IMX21LCDC_LGWCR 0x0064 /* LCDC Graphic Window Control Register */ +#define IMX21LCDC_LGWDCR 0x0068 /* LCDC Graphic Window DMA Control Register */ +#define IMX21LCDC_LAUSCR 0x0080 /* LCDC AUS Mode Control Register */ +#define IMX21LCDC_LAUSCCR 0x0084 /* LCDC AUS Mode Cursor Control Register */ +#define IMX21LCDC_BGLUT 0x0800 /* Background Lookup Table */ +#define IMX21LCDC_GWLUT 0x0C00 /* Graphic Window Lookup Table */ + +#define IMX21LCDC_LCPR_CC0 BIT(30) /* Cursor Control Bit 0 */ +#define IMX21LCDC_LCPR_CC1 BIT(31) /* Cursor Control Bit 1 */ + +/* Values HSYNC, VSYNC and Framesize Register */ +#define IMX21LCDC_LHCR_HWIDTH GENMASK(31, 26) +#define IMX21LCDC_LHCR_HFPORCH GENMASK(15, 8) /* H_WAIT_1 in the i.MX25 Reference manual */ +#define IMX21LCDC_LHCR_HBPORCH GENMASK(7, 0) /* H_WAIT_2 in the i.MX25 Reference manual */ + +#define IMX21LCDC_LVCR_VWIDTH GENMASK(31, 26) +#define IMX21LCDC_LVCR_VFPORCH GENMASK(15, 8) /* V_WAIT_1 in the i.MX25 Reference manual */ +#define IMX21LCDC_LVCR_VBPORCH GENMASK(7, 0) /* V_WAIT_2 in the i.MX25 Reference manual */ + +#define IMX21LCDC_LSR_XMAX GENMASK(25, 20) +#define IMX21LCDC_LSR_YMAX GENMASK(9, 0) + +/* Values for LPCR Register */ +#define IMX21LCDC_LPCR_PCD GENMASK(5, 0) +#define IMX21LCDC_LPCR_SHARP BIT(6) +#define IMX21LCDC_LPCR_SCLKSEL BIT(7) +#define IMX21LCDC_LPCR_ACD GENMASK(14, 8) +#define IMX21LCDC_LPCR_ACDSEL BIT(15) +#define IMX21LCDC_LPCR_REV_VS BIT(16) +#define IMX21LCDC_LPCR_SWAP_SEL BIT(17) +#define IMX21LCDC_LPCR_END_SEL BIT(18) +#define IMX21LCDC_LPCR_SCLKIDLE BIT(19) +#define IMX21LCDC_LPCR_OEPOL BIT(20) +#define IMX21LCDC_LPCR_CLKPOL BIT(21) +#define IMX21LCDC_LPCR_LPPOL BIT(22) +#define IMX21LCDC_LPCR_FLMPOL BIT(23) +#define IMX21LCDC_LPCR_PIXPOL BIT(24) +#define IMX21LCDC_LPCR_BPIX GENMASK(27, 25) +#define IMX21LCDC_LPCR_PBSIZ GENMASK(29, 28) +#define IMX21LCDC_LPCR_COLOR BIT(30) +#define IMX21LCDC_LPCR_TFT BIT(31) + +#define INTR_EOF BIT(1) /* VBLANK Interrupt Bit */ + +#define BPP_RGB565 0x05 +#define BPP_XRGB8888 0x07 + +#define LCDC_MIN_XRES 64 +#define LCDC_MIN_YRES 64 + +#define LCDC_MAX_XRES 1024 +#define LCDC_MAX_YRES 1024 + +struct imx_lcdc { + struct drm_device drm; + struct drm_simple_display_pipe pipe; + struct drm_connector *connector; + void __iomem *base; + + struct clk *clk_ipg; + struct clk *clk_ahb; + struct clk *clk_per; +}; + +static const u32 imx_lcdc_formats[] = { + DRM_FORMAT_RGB565, DRM_FORMAT_XRGB8888, +}; + +static inline struct imx_lcdc *imx_lcdc_from_drmdev(struct drm_device *drm) +{ + return container_of(drm, struct imx_lcdc, drm); +} + +static unsigned int imx_lcdc_get_format(unsigned int drm_format) +{ + switch (drm_format) { + default: + DRM_WARN("Format not supported - fallback to XRGB8888\n"); + fallthrough; + + case DRM_FORMAT_XRGB8888: + return BPP_XRGB8888; + + case DRM_FORMAT_RGB565: + return BPP_RGB565; + } +} + +static void imx_lcdc_update_hw_registers(struct drm_simple_display_pipe *pipe, + struct drm_plane_state *old_state, + bool mode_set) +{ + struct drm_crtc *crtc = &pipe->crtc; + struct drm_plane_state *new_state = pipe->plane.state; + struct drm_framebuffer *fb = new_state->fb; + struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev); + u32 lpcr, lvcr, lhcr; + u32 framesize; + dma_addr_t addr; + + addr = drm_fb_dma_get_gem_addr(fb, new_state, 0); + /* The LSSAR register specifies the LCD screen start address (SSA). */ + writel(addr, lcdc->base + IMX21LCDC_LSSAR); + + if (!mode_set) + return; + + /* Disable PER clock to make register write possible */ + if (old_state && old_state->crtc && old_state->crtc->enabled) + clk_disable_unprepare(lcdc->clk_per); + + /* Framesize */ + framesize = FIELD_PREP(IMX21LCDC_LSR_XMAX, crtc->mode.hdisplay >> 4) | + FIELD_PREP(IMX21LCDC_LSR_YMAX, crtc->mode.vdisplay); + writel(framesize, lcdc->base + IMX21LCDC_LSR); + + /* HSYNC */ + lhcr = FIELD_PREP(IMX21LCDC_LHCR_HFPORCH, crtc->mode.hsync_start - crtc->mode.hdisplay - 1) | + FIELD_PREP(IMX21LCDC_LHCR_HWIDTH, crtc->mode.hsync_end - crtc->mode.hsync_start - 1) | + FIELD_PREP(IMX21LCDC_LHCR_HBPORCH, crtc->mode.htotal - crtc->mode.hsync_end - 3); + writel(lhcr, lcdc->base + IMX21LCDC_LHCR); + + /* VSYNC */ + lvcr = FIELD_PREP(IMX21LCDC_LVCR_VFPORCH, crtc->mode.vsync_start - crtc->mode.vdisplay) | + FIELD_PREP(IMX21LCDC_LVCR_VWIDTH, crtc->mode.vsync_end - crtc->mode.vsync_start) | + FIELD_PREP(IMX21LCDC_LVCR_VBPORCH, crtc->mode.vtotal - crtc->mode.vsync_end); + writel(lvcr, lcdc->base + IMX21LCDC_LVCR); + + lpcr = readl(lcdc->base + IMX21LCDC_LPCR); + lpcr &= ~IMX21LCDC_LPCR_BPIX; + lpcr |= FIELD_PREP(IMX21LCDC_LPCR_BPIX, imx_lcdc_get_format(fb->format->format)); + writel(lpcr, lcdc->base + IMX21LCDC_LPCR); + + /* Virtual Page Width */ + writel(new_state->fb->pitches[0] / 4, lcdc->base + IMX21LCDC_LVPWR); + + /* Enable PER clock */ + if (new_state->crtc->enabled) + clk_prepare_enable(lcdc->clk_per); +} + +static void imx_lcdc_pipe_enable(struct drm_simple_display_pipe *pipe, + struct drm_crtc_state *crtc_state, + struct drm_plane_state *plane_state) +{ + int ret; + int clk_div; + int bpp; + struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev); + struct drm_display_mode *mode = &pipe->crtc.mode; + struct drm_display_info *disp_info = &lcdc->connector->display_info; + const int hsync_pol = (mode->flags & DRM_MODE_FLAG_PHSYNC) ? 0 : 1; + const int vsync_pol = (mode->flags & DRM_MODE_FLAG_PVSYNC) ? 0 : 1; + const int data_enable_pol = + (disp_info->bus_flags & DRM_BUS_FLAG_DE_HIGH) ? 0 : 1; + const int clk_pol = + (disp_info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE) ? 0 : 1; + + clk_div = DIV_ROUND_CLOSEST_ULL(clk_get_rate(lcdc->clk_per), + mode->clock * 1000); + bpp = imx_lcdc_get_format(plane_state->fb->format->format); + + writel(FIELD_PREP(IMX21LCDC_LPCR_PCD, clk_div - 1) | + FIELD_PREP(IMX21LCDC_LPCR_LPPOL, hsync_pol) | + FIELD_PREP(IMX21LCDC_LPCR_FLMPOL, vsync_pol) | + FIELD_PREP(IMX21LCDC_LPCR_OEPOL, data_enable_pol) | + FIELD_PREP(IMX21LCDC_LPCR_TFT, 1) | + FIELD_PREP(IMX21LCDC_LPCR_COLOR, 1) | + FIELD_PREP(IMX21LCDC_LPCR_PBSIZ, 3) | + FIELD_PREP(IMX21LCDC_LPCR_BPIX, bpp) | + FIELD_PREP(IMX21LCDC_LPCR_SCLKSEL, 1) | + FIELD_PREP(IMX21LCDC_LPCR_PIXPOL, 0) | + FIELD_PREP(IMX21LCDC_LPCR_CLKPOL, clk_pol), + lcdc->base + IMX21LCDC_LPCR); + + /* 0px panning offset */ + writel(0x00000000, lcdc->base + IMX21LCDC_LPOR); + + /* disable hardware cursor */ + writel(readl(lcdc->base + IMX21LCDC_LCPR) & ~(IMX21LCDC_LCPR_CC0 | IMX21LCDC_LCPR_CC1), + lcdc->base + IMX21LCDC_LCPR); + + ret = clk_prepare_enable(lcdc->clk_ipg); + if (ret) { + dev_err(pipe->crtc.dev->dev, "Cannot enable ipg clock: %pe\n", ERR_PTR(ret)); + return; + } + ret = clk_prepare_enable(lcdc->clk_ahb); + if (ret) { + dev_err(pipe->crtc.dev->dev, "Cannot enable ahb clock: %pe\n", ERR_PTR(ret)); + + clk_disable_unprepare(lcdc->clk_ipg); + + return; + } + + imx_lcdc_update_hw_registers(pipe, NULL, true); + + /* Enable VBLANK Interrupt */ + writel(INTR_EOF, lcdc->base + IMX21LCDC_LIER); +} + +static void imx_lcdc_pipe_disable(struct drm_simple_display_pipe *pipe) +{ + struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev); + struct drm_crtc *crtc = &lcdc->pipe.crtc; + struct drm_pending_vblank_event *event; + + clk_disable_unprepare(lcdc->clk_ahb); + clk_disable_unprepare(lcdc->clk_ipg); + + if (pipe->crtc.enabled) + clk_disable_unprepare(lcdc->clk_per); + + spin_lock_irq(&lcdc->drm.event_lock); + event = crtc->state->event; + if (event) { + crtc->state->event = NULL; + drm_crtc_send_vblank_event(crtc, event); + } + spin_unlock_irq(&lcdc->drm.event_lock); + + /* Disable VBLANK Interrupt */ + writel(0, lcdc->base + IMX21LCDC_LIER); +} + +static int imx_lcdc_pipe_check(struct drm_simple_display_pipe *pipe, + struct drm_plane_state *plane_state, + struct drm_crtc_state *crtc_state) +{ + const struct drm_display_mode *mode = &crtc_state->mode; + const struct drm_display_mode *old_mode = &pipe->crtc.state->mode; + + if (mode->hdisplay < LCDC_MIN_XRES || mode->hdisplay > LCDC_MAX_XRES || + mode->vdisplay < LCDC_MIN_YRES || mode->vdisplay > LCDC_MAX_YRES || + mode->hdisplay % 0x10) { /* must be multiple of 16 */ + drm_err(pipe->crtc.dev, "unsupported display mode (%u x %u)\n", + mode->hdisplay, mode->vdisplay); + return -EINVAL; + } + + crtc_state->mode_changed = + old_mode->hdisplay != mode->hdisplay || + old_mode->vdisplay != mode->vdisplay; + + return 0; +} + +static void imx_lcdc_pipe_update(struct drm_simple_display_pipe *pipe, + struct drm_plane_state *old_state) +{ + struct drm_crtc *crtc = &pipe->crtc; + struct drm_pending_vblank_event *event = crtc->state->event; + struct drm_plane_state *new_state = pipe->plane.state; + struct drm_framebuffer *fb = new_state->fb; + struct drm_framebuffer *old_fb = old_state->fb; + struct drm_crtc *old_crtc = old_state->crtc; + bool mode_changed = false; + + if (old_fb && old_fb->format != fb->format) + mode_changed = true; + else if (old_crtc != crtc) + mode_changed = true; + + imx_lcdc_update_hw_registers(pipe, old_state, mode_changed); + + if (event) { + crtc->state->event = NULL; + + spin_lock_irq(&crtc->dev->event_lock); + + if (crtc->state->active && drm_crtc_vblank_get(crtc) == 0) + drm_crtc_arm_vblank_event(crtc, event); + else + drm_crtc_send_vblank_event(crtc, event); + + spin_unlock_irq(&crtc->dev->event_lock); + } +} + +static const struct drm_simple_display_pipe_funcs imx_lcdc_pipe_funcs = { + .enable = imx_lcdc_pipe_enable, + .disable = imx_lcdc_pipe_disable, + .check = imx_lcdc_pipe_check, + .update = imx_lcdc_pipe_update, +}; + +static const struct drm_mode_config_funcs imx_lcdc_mode_config_funcs = { + .fb_create = drm_gem_fb_create_with_dirty, + .atomic_check = drm_atomic_helper_check, + .atomic_commit = drm_atomic_helper_commit, +}; + +static const struct drm_mode_config_helper_funcs imx_lcdc_mode_config_helpers = { + .atomic_commit_tail = drm_atomic_helper_commit_tail_rpm, +}; + +static void imx_lcdc_release(struct drm_device *drm) +{ + struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(drm); + + drm_kms_helper_poll_fini(drm); + kfree(lcdc); +} + +DEFINE_DRM_GEM_DMA_FOPS(imx_lcdc_drm_fops); + +static struct drm_driver imx_lcdc_drm_driver = { + .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC, + .fops = &imx_lcdc_drm_fops, + DRM_GEM_DMA_DRIVER_OPS_VMAP, + .release = imx_lcdc_release, + .name = "imx-lcdc", + .desc = "i.MX LCDC driver", + .date = "20200716", +}; + +static const struct of_device_id imx_lcdc_of_dev_id[] = { + { + .compatible = "fsl,imx21-lcdc", + }, + { + .compatible = "fsl,imx25-lcdc", + }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, imx_lcdc_of_dev_id); + +static irqreturn_t imx_lcdc_irq_handler(int irq, void *arg) +{ + struct imx_lcdc *lcdc = arg; + struct drm_crtc *crtc = &lcdc->pipe.crtc; + unsigned int status; + + status = readl(lcdc->base + IMX21LCDC_LISR); + + if (status & INTR_EOF) { + drm_crtc_handle_vblank(crtc); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int imx_lcdc_probe(struct platform_device *pdev) +{ + struct imx_lcdc *lcdc; + struct drm_device *drm; + struct drm_bridge *bridge; + int irq; + int ret; + struct device *dev = &pdev->dev; + + lcdc = devm_drm_dev_alloc(dev, &imx_lcdc_drm_driver, + struct imx_lcdc, drm); + if (!lcdc) + return -ENOMEM; + + drm = &lcdc->drm; + + lcdc->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(lcdc->base)) + return dev_err_probe(dev, PTR_ERR(lcdc->base), "Cannot get IO memory\n"); + + bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0); + if (IS_ERR(bridge)) + return dev_err_probe(dev, PTR_ERR(bridge), "Failed to find bridge\n"); + + /* Get Clocks */ + lcdc->clk_ipg = devm_clk_get(dev, "ipg"); + if (IS_ERR(lcdc->clk_ipg)) + return dev_err_probe(dev, PTR_ERR(lcdc->clk_ipg), "Failed to get %s clk\n", "ipg"); + + lcdc->clk_ahb = devm_clk_get(dev, "ahb"); + if (IS_ERR(lcdc->clk_ahb)) + return dev_err_probe(dev, PTR_ERR(lcdc->clk_ahb), "Failed to get %s clk\n", "ahb"); + + lcdc->clk_per = devm_clk_get(dev, "per"); + if (IS_ERR(lcdc->clk_per)) + return dev_err_probe(dev, PTR_ERR(lcdc->clk_per), "Failed to get %s clk\n", "per"); + + ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32)); + if (ret) + return dev_err_probe(dev, ret, "Cannot set DMA Mask\n"); + + /* Modeset init */ + ret = drmm_mode_config_init(drm); + if (ret) + return dev_err_probe(dev, ret, "Cannot initialize mode configuration structure\n"); + + /* CRTC, Plane, Encoder */ + ret = drm_simple_display_pipe_init(drm, &lcdc->pipe, + &imx_lcdc_pipe_funcs, + imx_lcdc_formats, + ARRAY_SIZE(imx_lcdc_formats), NULL, NULL); + if (ret < 0) + return dev_err_probe(drm->dev, ret, "Cannot setup simple display pipe\n"); + + ret = drm_vblank_init(drm, drm->mode_config.num_crtc); + if (ret < 0) + return dev_err_probe(drm->dev, ret, "Failed to initialize vblank\n"); + + ret = drm_bridge_attach(&lcdc->pipe.encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR); + if (ret) + return dev_err_probe(drm->dev, ret, "Cannot attach bridge\n"); + + lcdc->connector = drm_bridge_connector_init(drm, &lcdc->pipe.encoder); + if (IS_ERR(lcdc->connector)) + return dev_err_probe(drm->dev, PTR_ERR(lcdc->connector), "Cannot init bridge connector\n"); + + drm_connector_attach_encoder(lcdc->connector, &lcdc->pipe.encoder); + + /* + * The LCDC controller does not have an enable bit. The + * controller starts directly when the clocks are enabled. + * If the clocks are enabled when the controller is not yet + * programmed with proper register values (enabled at the + * bootloader, for example) then it just goes into some undefined + * state. + * To avoid this issue, let's enable and disable LCDC IPG, + * PER and AHB clock so that we force some kind of 'reset' + * to the LCDC block. + */ + + ret = clk_prepare_enable(lcdc->clk_ipg); + if (ret) + return dev_err_probe(dev, ret, "Cannot enable ipg clock\n"); + clk_disable_unprepare(lcdc->clk_ipg); + + ret = clk_prepare_enable(lcdc->clk_per); + if (ret) + return dev_err_probe(dev, ret, "Cannot enable per clock\n"); + clk_disable_unprepare(lcdc->clk_per); + + ret = clk_prepare_enable(lcdc->clk_ahb); + if (ret) + return dev_err_probe(dev, ret, "Cannot enable ahb clock\n"); + clk_disable_unprepare(lcdc->clk_ahb); + + drm->mode_config.min_width = LCDC_MIN_XRES; + drm->mode_config.max_width = LCDC_MAX_XRES; + drm->mode_config.min_height = LCDC_MIN_YRES; + drm->mode_config.max_height = LCDC_MAX_YRES; + drm->mode_config.preferred_depth = 16; + drm->mode_config.funcs = &imx_lcdc_mode_config_funcs; + drm->mode_config.helper_private = &imx_lcdc_mode_config_helpers; + + drm_mode_config_reset(drm); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + ret = irq; + return ret; + } + + ret = devm_request_irq(dev, irq, imx_lcdc_irq_handler, 0, "imx-lcdc", lcdc); + if (ret < 0) + return dev_err_probe(drm->dev, ret, "Failed to install IRQ handler\n"); + + platform_set_drvdata(pdev, drm); + + ret = drm_dev_register(&lcdc->drm, 0); + if (ret) + return dev_err_probe(dev, ret, "Cannot register device\n"); + + drm_fbdev_generic_setup(drm, 0); + + return 0; +} + +static int imx_lcdc_remove(struct platform_device *pdev) +{ + struct drm_device *drm = platform_get_drvdata(pdev); + + drm_dev_unregister(drm); + drm_atomic_helper_shutdown(drm); + + return 0; +} + +static void imx_lcdc_shutdown(struct platform_device *pdev) +{ + drm_atomic_helper_shutdown(platform_get_drvdata(pdev)); +} + +static struct platform_driver imx_lcdc_driver = { + .driver = { + .name = "imx-lcdc", + .of_match_table = imx_lcdc_of_dev_id, + }, + .probe = imx_lcdc_probe, + .remove = imx_lcdc_remove, + .shutdown = imx_lcdc_shutdown, +}; +module_platform_driver(imx_lcdc_driver); + +MODULE_AUTHOR("Marian Cichy "); +MODULE_DESCRIPTION("Freescale i.MX LCDC driver"); +MODULE_LICENSE("GPL");