Re: [PATCH 6/6] drm/meson: add support for MIPI-DSI transceiver

[Daniel Vetter]

On Mon, Sep 07, 2020 at 10:18:25AM +0200, Neil Armstrong wrote:
> The Amlogic AXg SoCs embeds a Synopsys DW-MIPI-DSI transceiver (ver 1.21a), with a custom
> glue managing the IP resets, clock and data input similar to the DW-HDMI Glue on other
> Amlogic SoCs.
> 
> This adds support for the Glue managing the transceiver, mimicing the init flow provided
> by Amlogic to setup the ENCl encoder, the glue, the transceiver, the digital D-PHY and the
> Analog PHY in the proper way.
> 
> The DW-MIPI-DSI transceiver + D-PHY are directly clocked by the VCLK2 clock, which pixel clock
> is derived and feeds the ENCL encoder and the VIU pixel reader.
> 
> An optional "MEAS" clock can be enabled to measure the delay between each vsync feeding the
> DW-MIPI-DSI transceiver.
> 
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>

More dw-hdmi drivers which aren't bridges but components, and the thing is
still midlayer-y as heck :-/

Can we try to fix this? There's a ton of this going on, and the more we
add the old fashioned way the harder this gets to fix up for real.
-Daniel

> ---
>  drivers/gpu/drm/meson/Kconfig             |   7 +
>  drivers/gpu/drm/meson/Makefile            |   1 +
>  drivers/gpu/drm/meson/meson_dw_mipi_dsi.c | 562 ++++++++++++++++++++++
>  3 files changed, 570 insertions(+)
>  create mode 100644 drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> 
> diff --git a/drivers/gpu/drm/meson/Kconfig b/drivers/gpu/drm/meson/Kconfig
> index 9f9281dd49f8..385f6f23839b 100644
> --- a/drivers/gpu/drm/meson/Kconfig
> +++ b/drivers/gpu/drm/meson/Kconfig
> @@ -16,3 +16,10 @@ config DRM_MESON_DW_HDMI
>  	default y if DRM_MESON
>  	select DRM_DW_HDMI
>  	imply DRM_DW_HDMI_I2S_AUDIO
> +
> +config DRM_MESON_DW_MIPI_DSI
> +	tristate "MIPI DSI Synopsys Controller support for Amlogic Meson Display"
> +	depends on DRM_MESON
> +	default y if DRM_MESON
> +	select DRM_DW_MIPI_DSI
> +	select GENERIC_PHY_MIPI_DPHY
> diff --git a/drivers/gpu/drm/meson/Makefile b/drivers/gpu/drm/meson/Makefile
> index 28a519cdf66b..2cc870e91182 100644
> --- a/drivers/gpu/drm/meson/Makefile
> +++ b/drivers/gpu/drm/meson/Makefile
> @@ -5,3 +5,4 @@ meson-drm-y += meson_rdma.o meson_osd_afbcd.o
>  
>  obj-$(CONFIG_DRM_MESON) += meson-drm.o
>  obj-$(CONFIG_DRM_MESON_DW_HDMI) += meson_dw_hdmi.o
> +obj-$(CONFIG_DRM_MESON_DW_MIPI_DSI) += meson_dw_mipi_dsi.o
> diff --git a/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c b/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> new file mode 100644
> index 000000000000..bbe1294fce7c
> --- /dev/null
> +++ b/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> @@ -0,0 +1,562 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2016 BayLibre, SAS
> + * Author: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> + * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/component.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/of_graph.h>
> +#include <linux/reset.h>
> +#include <linux/phy/phy.h>
> +
> +#include <video/mipi_display.h>
> +
> +#include <drm/bridge/dw_mipi_dsi.h>
> +#include <drm/drm_mipi_dsi.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_device.h>
> +#include <drm/drm_probe_helper.h>
> +#include <drm/drm_print.h>
> +
> +#include "meson_drv.h"
> +#include "meson_dw_mipi_dsi.h"
> +#include "meson_registers.h"
> +#include "meson_venc.h"
> +
> +#define DRIVER_NAME "meson-dw-mipi-dsi"
> +#define DRIVER_DESC "Amlogic Meson MIPI-DSI DRM driver"
> +
> +/*  MIPI DSI/VENC Color Format Definitions */
> +#define MIPI_DSI_VENC_COLOR_30B   0x0
> +#define MIPI_DSI_VENC_COLOR_24B   0x1
> +#define MIPI_DSI_VENC_COLOR_18B   0x2
> +#define MIPI_DSI_VENC_COLOR_16B   0x3
> +
> +#define COLOR_16BIT_CFG_1         0x0
> +#define COLOR_16BIT_CFG_2         0x1
> +#define COLOR_16BIT_CFG_3         0x2
> +#define COLOR_18BIT_CFG_1         0x3
> +#define COLOR_18BIT_CFG_2         0x4
> +#define COLOR_24BIT               0x5
> +#define COLOR_20BIT_LOOSE         0x6
> +#define COLOR_24_BIT_YCBCR        0x7
> +#define COLOR_16BIT_YCBCR         0x8
> +#define COLOR_30BIT               0x9
> +#define COLOR_36BIT               0xa
> +#define COLOR_12BIT               0xb
> +#define COLOR_RGB_111             0xc
> +#define COLOR_RGB_332             0xd
> +#define COLOR_RGB_444             0xe
> +
> +/*  MIPI DSI Relative REGISTERs Definitions */
> +/* For MIPI_DSI_TOP_CNTL */
> +#define BIT_DPI_COLOR_MODE        20
> +#define BIT_IN_COLOR_MODE         16
> +#define BIT_CHROMA_SUBSAMPLE      14
> +#define BIT_COMP2_SEL             12
> +#define BIT_COMP1_SEL             10
> +#define BIT_COMP0_SEL              8
> +#define BIT_DE_POL                 6
> +#define BIT_HSYNC_POL              5
> +#define BIT_VSYNC_POL              4
> +#define BIT_DPICOLORM              3
> +#define BIT_DPISHUTDN              2
> +#define BIT_EDPITE_INTR_PULSE      1
> +#define BIT_ERR_INTR_PULSE         0
> +
> +/* HHI Registers */
> +#define HHI_VIID_CLK_DIV	0x128 /* 0x4a offset in data sheet */
> +#define VCLK2_DIV_MASK		0xff
> +#define VCLK2_DIV_EN		BIT(16)
> +#define VCLK2_DIV_RESET		BIT(17)
> +#define CTS_ENCL_SEL_MASK	(0xf << 12)
> +#define CTS_ENCL_SEL_SHIFT	12
> +#define HHI_VIID_CLK_CNTL	0x12c /* 0x4b offset in data sheet */
> +#define VCLK2_EN		BIT(19)
> +#define VCLK2_SEL_MASK		(0x7 << 16)
> +#define VCLK2_SEL_SHIFT		16
> +#define VCLK2_SOFT_RESET	BIT(15)
> +#define VCLK2_DIV1_EN		BIT(0)
> +#define HHI_VID_CLK_CNTL2	0x194 /* 0x65 offset in data sheet */
> +#define CTS_ENCL_EN		BIT(3)
> +
> +/**
> + * DOC: MIPI DSI
> + *
> + */
> +
> +struct meson_dw_mipi_dsi {
> +	struct drm_encoder encoder;
> +	struct meson_drm *priv;
> +	struct device *dev;
> +	void __iomem *base;
> +	struct phy *phy;
> +	union phy_configure_opts phy_opts;
> +	struct dw_mipi_dsi *dmd;
> +	struct dw_mipi_dsi_plat_data pdata;
> +	struct mipi_dsi_device *dsi_device;
> +	unsigned long mode_flags;
> +	struct clk *px_clk;
> +};
> +#define encoder_to_meson_dw_mipi_dsi(x) \
> +	container_of(x, struct meson_dw_mipi_dsi, encoder)
> +
> +static void dw_mipi_dsi_set_vclk(struct meson_dw_mipi_dsi *mipi_dsi,
> +				 struct drm_display_mode *mode)
> +{
> +	struct meson_drm *priv = mipi_dsi->priv;
> +	unsigned int vclk2_div;
> +	unsigned int pll_rate;
> +	int ret;
> +
> +	pll_rate = mipi_dsi->phy_opts.mipi_dphy.hs_clk_rate;
> +	vclk2_div = pll_rate / (mode->clock * 1000);
> +
> +	ret = clk_set_rate(mipi_dsi->px_clk, pll_rate);
> +	if (ret) {
> +		pr_err("Failed to set DSI PLL rate %lu\n",
> +		       mipi_dsi->phy_opts.mipi_dphy.hs_clk_rate);
> +
> +		return;
> +	}
> +
> +	/* Disable VCLK2 */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_CNTL, VCLK2_EN, 0);
> +
> +	/* Setup the VCLK2 divider value */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_DIV,
> +				VCLK2_DIV_MASK, (vclk2_div - 1));
> +
> +	/* select gp0 for vclk2 */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_CNTL,
> +				VCLK2_SEL_MASK, (0 << VCLK2_SEL_SHIFT));
> +
> +	/* enable vclk2 gate */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_CNTL, VCLK2_EN, VCLK2_EN);
> +
> +	/* select vclk2_div1 for encl */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_DIV,
> +				CTS_ENCL_SEL_MASK, (8 << CTS_ENCL_SEL_SHIFT));
> +
> +	/* release vclk2_div_reset and enable vclk2_div */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_DIV,
> +				VCLK2_DIV_EN | VCLK2_DIV_RESET, VCLK2_DIV_EN);
> +
> +	/* enable vclk2_div1 gate */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_CNTL,
> +				VCLK2_DIV1_EN, VCLK2_DIV1_EN);
> +
> +	/* reset vclk2 */
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_CNTL,
> +				VCLK2_SOFT_RESET, VCLK2_SOFT_RESET);
> +	regmap_update_bits(priv->hhi, HHI_VIID_CLK_CNTL,
> +				VCLK2_SOFT_RESET, 0);
> +
> +	/* enable encl_clk */
> +	regmap_update_bits(priv->hhi, HHI_VID_CLK_CNTL2,
> +				CTS_ENCL_EN, CTS_ENCL_EN);
> +
> +	usleep_range(10000, 11000);
> +}
> +
> +static int dw_mipi_dsi_phy_init(void *priv_data)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = priv_data;
> +	struct meson_drm *priv = mipi_dsi->priv;
> +
> +
> +	phy_power_on(mipi_dsi->phy);
> +
> +	writel_relaxed(1, priv->io_base + _REG(ENCL_VIDEO_EN));
> +
> +	return 0;
> +}
> +
> +static void dw_mipi_dsi_phy_power_off(void *priv_data)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = priv_data;
> +
> +	phy_power_off(mipi_dsi->phy);
> +}
> +
> +static int
> +dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
> +			  unsigned long mode_flags, u32 lanes, u32 format,
> +			  unsigned int *lane_mbps)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = priv_data;
> +
> +	*lane_mbps = mipi_dsi->phy_opts.mipi_dphy.hs_clk_rate / 1000000;
> +
> +	return 0;
> +}
> +
> +static int
> +dw_mipi_dsi_phy_get_timing(void *priv_data, unsigned int lane_mbps,
> +			   struct dw_mipi_dsi_dphy_timing *timing)
> +{
> +	/* TOFIX handle other cases */
> +
> +	timing->clk_lp2hs = 37;
> +	timing->clk_hs2lp = 135;
> +	timing->data_lp2hs = 50;
> +	timing->data_hs2lp = 3;
> +
> +	return 0;
> +}
> +
> +static int
> +dw_mipi_dsi_get_esc_clk_rate(void *priv_data, unsigned int *esc_clk_rate)
> +{
> +	*esc_clk_rate = 4; /* Mhz */
> +
> +	return 0;
> +}
> +
> +static const struct dw_mipi_dsi_phy_ops meson_dw_mipi_dsi_phy_ops = {
> +	.init = dw_mipi_dsi_phy_init,
> +	.power_off = dw_mipi_dsi_phy_power_off,
> +	.get_lane_mbps = dw_mipi_dsi_get_lane_mbps,
> +	.get_timing = dw_mipi_dsi_phy_get_timing,
> +	.get_esc_clk_rate = dw_mipi_dsi_get_esc_clk_rate,
> +};
> +
> +/* Encoder */
> +
> +static void meson_mipi_dsi_encoder_destroy(struct drm_encoder *encoder)
> +{
> +	drm_encoder_cleanup(encoder);
> +}
> +
> +static const struct drm_encoder_funcs meson_mipi_dsi_encoder_funcs = {
> +	.destroy        = meson_mipi_dsi_encoder_destroy,
> +};
> +
> +static int meson_mipi_dsi_encoder_atomic_check(struct drm_encoder *encoder,
> +					struct drm_crtc_state *crtc_state,
> +					struct drm_connector_state *conn_state)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi =
> +			encoder_to_meson_dw_mipi_dsi(encoder);
> +
> +	switch (mipi_dsi->dsi_device->format) {
> +	case MIPI_DSI_FMT_RGB888:
> +		break;
> +	case MIPI_DSI_FMT_RGB666:
> +		break;
> +	case MIPI_DSI_FMT_RGB666_PACKED:
> +	case MIPI_DSI_FMT_RGB565:
> +	default:
> +		DRM_DEV_ERROR(mipi_dsi->dev,
> +				"invalid pixel format %d\n",
> +				mipi_dsi->dsi_device->format);
> +		return -EINVAL;
> +	};
> +
> +	return 0;
> +}
> +
> +static void meson_mipi_dsi_encoder_disable(struct drm_encoder *encoder)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi =
> +			encoder_to_meson_dw_mipi_dsi(encoder);
> +	struct meson_drm *priv = mipi_dsi->priv;
> +
> +	writel_relaxed(0, priv->io_base + _REG(ENCL_VIDEO_EN));
> +}
> +
> +static void meson_mipi_dsi_encoder_enable(struct drm_encoder *encoder)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi =
> +			encoder_to_meson_dw_mipi_dsi(encoder);
> +	struct meson_drm *priv = mipi_dsi->priv;
> +
> +	writel_bits_relaxed(BIT(3), BIT(3),
> +			priv->io_base + _REG(ENCL_VIDEO_MODE_ADV));
> +	writel_relaxed(0, priv->io_base + _REG(ENCL_TST_EN));
> +}
> +
> +static void meson_dw_mipi_dsi_init(struct meson_dw_mipi_dsi *mipi_dsi)
> +{
> +	writel_relaxed((1 << 4) | (1 << 5) | (0 << 6),
> +			mipi_dsi->base + MIPI_DSI_TOP_CNTL);
> +
> +	writel_bits_relaxed(0xf, 0xf,
> +			    mipi_dsi->base + MIPI_DSI_TOP_SW_RESET);
> +	writel_bits_relaxed(0xf, 0,
> +			    mipi_dsi->base + MIPI_DSI_TOP_SW_RESET);
> +
> +	writel_bits_relaxed(0x3, 0x3,
> +			    mipi_dsi->base + MIPI_DSI_TOP_CLK_CNTL);
> +
> +	writel_relaxed(0, mipi_dsi->base + MIPI_DSI_TOP_MEM_PD);
> +}
> +
> +static void meson_mipi_dsi_encoder_mode_set(struct drm_encoder *encoder,
> +				   struct drm_display_mode *mode,
> +				   struct drm_display_mode *adjusted_mode)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = encoder_to_meson_dw_mipi_dsi(encoder);
> +	unsigned int dpi_data_format, venc_data_width;
> +	struct meson_drm *priv = mipi_dsi->priv;
> +	int bpp;
> +	u32 reg;
> +
> +	mipi_dsi->mode_flags = mode->flags;
> +
> +	bpp = mipi_dsi_pixel_format_to_bpp(mipi_dsi->dsi_device->format);
> +
> +	phy_mipi_dphy_get_default_config(mode->clock * 1000,
> +					 bpp, mipi_dsi->dsi_device->lanes,
> +					 &mipi_dsi->phy_opts.mipi_dphy);
> +
> +	phy_configure(mipi_dsi->phy, &mipi_dsi->phy_opts);
> +
> +	switch (mipi_dsi->dsi_device->format) {
> +	case MIPI_DSI_FMT_RGB888:
> +		dpi_data_format = COLOR_24BIT;
> +		venc_data_width = MIPI_DSI_VENC_COLOR_24B;
> +		break;
> +	case MIPI_DSI_FMT_RGB666:
> +		dpi_data_format = COLOR_18BIT_CFG_2;
> +		venc_data_width = MIPI_DSI_VENC_COLOR_18B;
> +		break;
> +	case MIPI_DSI_FMT_RGB666_PACKED:
> +	case MIPI_DSI_FMT_RGB565:
> +		/* invalid */
> +		break;
> +	};
> +
> +	dw_mipi_dsi_set_vclk(mipi_dsi, mode);
> +	meson_venc_mipi_dsi_mode_set(priv, mode);
> +
> +	meson_encl_load_gamma(priv);
> +
> +	writel_relaxed(0, priv->io_base + _REG(ENCL_VIDEO_EN));
> +
> +	meson_dw_mipi_dsi_init(mipi_dsi);
> +
> +	/* Configure Set color format for DPI register */
> +	reg = readl_relaxed(mipi_dsi->base + MIPI_DSI_TOP_CNTL) &
> +		~(0xf<<BIT_DPI_COLOR_MODE) &
> +		~(0x7<<BIT_IN_COLOR_MODE) &
> +		~(0x3<<BIT_CHROMA_SUBSAMPLE);
> +
> +	writel_relaxed(reg |
> +		(dpi_data_format  << BIT_DPI_COLOR_MODE)  |
> +		(venc_data_width  << BIT_IN_COLOR_MODE) |
> +		0 << BIT_COMP0_SEL |
> +		1 << BIT_COMP1_SEL |
> +		2 << BIT_COMP2_SEL |
> +		(mipi_dsi->mode_flags & DRM_MODE_FLAG_NHSYNC ? 0 : BIT(BIT_HSYNC_POL)) |
> +		(mipi_dsi->mode_flags & DRM_MODE_FLAG_NVSYNC ? 0 : BIT(BIT_VSYNC_POL)),
> +		mipi_dsi->base + MIPI_DSI_TOP_CNTL);
> +}
> +
> +static const struct drm_encoder_helper_funcs
> +				meson_mipi_dsi_encoder_helper_funcs = {
> +	.atomic_check	= meson_mipi_dsi_encoder_atomic_check,
> +	.disable	= meson_mipi_dsi_encoder_disable,
> +	.enable		= meson_mipi_dsi_encoder_enable,
> +	.mode_set	= meson_mipi_dsi_encoder_mode_set,
> +};
> +
> +static int meson_dw_mipi_dsi_bind(struct device *dev, struct device *master,
> +				void *data)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = dev_get_drvdata(dev);
> +	struct drm_device *drm = data;
> +	struct meson_drm *priv = drm->dev_private;
> +	struct drm_encoder *encoder;
> +	int ret;
> +
> +	/* Check before if we are supposed to have a sub-device... */
> +	if (!mipi_dsi->dsi_device)
> +		return -EPROBE_DEFER;
> +
> +	encoder = &mipi_dsi->encoder;
> +	mipi_dsi->priv = priv;
> +
> +	/* Encoder */
> +	ret = drm_encoder_init(drm, encoder, &meson_mipi_dsi_encoder_funcs,
> +			       DRM_MODE_ENCODER_DSI, "meson_mipi_dsi");
> +	if (ret) {
> +		dev_err(priv->dev, "Failed to init DSI encoder\n");
> +		return ret;
> +	}
> +
> +	drm_encoder_helper_add(encoder, &meson_mipi_dsi_encoder_helper_funcs);
> +
> +	encoder->possible_crtcs = BIT(0);
> +
> +	ret = dw_mipi_dsi_bind(mipi_dsi->dmd, encoder);
> +	if (ret) {
> +		DRM_DEV_ERROR(dev, "Failed to bind: %d\n", ret);
> +		return ret;
> +	}
> +
> +	phy_init(mipi_dsi->phy);
> +
> +	return 0;
> +}
> +
> +static void meson_dw_mipi_dsi_unbind(struct device *dev, struct device *master,
> +				   void *data)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = dev_get_drvdata(dev);
> +
> +	dw_mipi_dsi_remove(mipi_dsi->dmd);
> +
> +	phy_exit(mipi_dsi->phy);
> +}
> +
> +static const struct component_ops meson_dw_mipi_dsi_ops = {
> +	.bind	= meson_dw_mipi_dsi_bind,
> +	.unbind	= meson_dw_mipi_dsi_unbind,
> +};
> +
> +static int meson_dw_mipi_dsi_host_attach(void *priv_data,
> +					 struct mipi_dsi_device *device)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = priv_data;
> +
> +	mipi_dsi->dsi_device = device;
> +
> +	return 0;
> +}
> +
> +static int meson_dw_mipi_dsi_host_detach(void *priv_data,
> +					 struct mipi_dsi_device *device)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = priv_data;
> +
> +	if (device == mipi_dsi->dsi_device)
> +		mipi_dsi->dsi_device = NULL;
> +	else
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static const struct dw_mipi_dsi_host_ops meson_dw_mipi_dsi_host_ops = {
> +	.attach = meson_dw_mipi_dsi_host_attach,
> +	.detach = meson_dw_mipi_dsi_host_detach,
> +};
> +
> +static int meson_dw_mipi_dsi_probe(struct platform_device *pdev)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi;
> +	struct reset_control *top_rst;
> +	struct resource *res;
> +	int ret;
> +
> +	mipi_dsi = devm_kzalloc(&pdev->dev, sizeof(*mipi_dsi), GFP_KERNEL);
> +	if (!mipi_dsi)
> +		return -ENOMEM;
> +
> +	mipi_dsi->dev = &pdev->dev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	mipi_dsi->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(mipi_dsi->base))
> +		return PTR_ERR(mipi_dsi->base);
> +
> +	mipi_dsi->phy = devm_phy_get(&pdev->dev, "dphy");
> +	if (IS_ERR(mipi_dsi->phy)) {
> +		ret = PTR_ERR(mipi_dsi->phy);
> +		dev_err(&pdev->dev, "failed to get mipi dphy: %d\n", ret);
> +		return ret;
> +	}
> +
> +	mipi_dsi->px_clk = devm_clk_get(&pdev->dev, "px_clk");
> +	if (IS_ERR(mipi_dsi->px_clk)) {
> +		dev_err(&pdev->dev, "Unable to get PLL clk\n");
> +		return PTR_ERR(mipi_dsi->px_clk);
> +	}
> +
> +	/*
> +	 * We use a TOP reset signal because the APB reset signal
> +	 * is handled by the TOP control registers.
> +	 */
> +	top_rst = devm_reset_control_get_exclusive(&pdev->dev, "top");
> +	if (IS_ERR(top_rst)) {
> +		ret = PTR_ERR(top_rst);
> +
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "Unable to get reset control: %d\n", ret);
> +
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(mipi_dsi->px_clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Unable to prepare/enable PX clock\n");
> +		goto err_clkdisable;
> +	}
> +
> +	reset_control_assert(top_rst);
> +	usleep_range(10, 20);
> +	reset_control_deassert(top_rst);
> +
> +	/* MIPI DSI Controller */
> +
> +	mipi_dsi->pdata.base = mipi_dsi->base;
> +	mipi_dsi->pdata.max_data_lanes = 4;
> +	mipi_dsi->pdata.phy_ops = &meson_dw_mipi_dsi_phy_ops;
> +	mipi_dsi->pdata.host_ops = &meson_dw_mipi_dsi_host_ops;
> +	mipi_dsi->pdata.priv_data = mipi_dsi;
> +	platform_set_drvdata(pdev, mipi_dsi);
> +
> +	mipi_dsi->dmd = dw_mipi_dsi_probe(pdev, &mipi_dsi->pdata);
> +	if (IS_ERR(mipi_dsi->dmd)) {
> +		ret = PTR_ERR(mipi_dsi->dmd);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(&pdev->dev,
> +				"Failed to probe dw_mipi_dsi: %d\n", ret);
> +		goto err_clkdisable;
> +	}
> +
> +	return component_add(mipi_dsi->dev, &meson_dw_mipi_dsi_ops);
> +
> +err_clkdisable:
> +	clk_disable_unprepare(mipi_dsi->px_clk);
> +
> +	return ret;
> +}
> +
> +static int meson_dw_mipi_dsi_remove(struct platform_device *pdev)
> +{
> +	struct meson_dw_mipi_dsi *mipi_dsi = dev_get_drvdata(&pdev->dev);
> +
> +	component_del(mipi_dsi->dev, &meson_dw_mipi_dsi_ops);
> +
> +	clk_disable_unprepare(mipi_dsi->px_clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id meson_dw_mipi_dsi_of_table[] = {
> +	{ .compatible = "amlogic,meson-axg-dw-mipi-dsi", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, meson_dw_mipi_dsi_of_table);
> +
> +static struct platform_driver meson_dw_mipi_dsi_platform_driver = {
> +	.probe		= meson_dw_mipi_dsi_probe,
> +	.remove		= meson_dw_mipi_dsi_remove,
> +	.driver		= {
> +		.name		= DRIVER_NAME,
> +		.of_match_table	= meson_dw_mipi_dsi_of_table,
> +	},
> +};
> +module_platform_driver(meson_dw_mipi_dsi_platform_driver);
> +
> +MODULE_AUTHOR("Neil Armstrong <narmstrong@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION(DRIVER_DESC);
> +MODULE_LICENSE("GPL");
> -- 
> 2.22.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch