Re: [PATCH v2 2/2] drm/bridge: Add tc358768 driver

[Peter Ujfalusi]

Hi Andrzej,

On 24/01/2020 16.27, Andrzej Hajda wrote:
>> +static void tc358768_write(struct tc358768_priv *priv, u32 reg, u32 val)
>> +{
>> +	size_t count = 2;
>> +
>> +	if (priv->error)
>> +		return;
>> +
>> +	/* 16-bit register? */
>> +	if (reg < 0x100 || reg >= 0x600)
>> +		count = 1;
>> +
>> +	priv->error = regmap_bulk_write(priv->regmap, reg, &val, count);
> 
> 
> Maybe it would be good to log possible error here and after regmap*read,
> to have more precise info, unless such log is provided already by
> regmap, up to you.

Regmap will tell us if a transfer fail when debugging is enabled.

>> +}
>> +
>> +static void tc358768_read(struct tc358768_priv *priv, u32 reg, u32 *val)
>> +{
>> +	size_t count = 2;
>> +
>> +	if (priv->error)
>> +		return;
>> +
>> +	/* 16-bit register? */
>> +	if (reg < 0x100 || reg >= 0x600) {
>> +		*val = 0;
>> +		count = 1;
>> +	}
>> +
>> +	priv->error = regmap_bulk_read(priv->regmap, reg, val, count);
>> +}
>> +
>> +static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask,
>> +				 u32 val)
>> +{
>> +	u32 tmp, orig;
>> +
>> +	tc358768_read(priv, reg, &orig);
>> +	tmp = orig & ~mask;
>> +	tmp |= val & mask;
>> +	if (tmp != orig)
>> +		tc358768_write(priv, reg, tmp);
>> +}
>> +
>> +static int tc358768_sw_reset(struct tc358768_priv *priv)
>> +{
>> +	/* Assert Reset */
>> +	tc358768_write(priv, TC358768_SYSCTL, 1);
>> +	/* Release Reset, Exit Sleep */
>> +	tc358768_write(priv, TC358768_SYSCTL, 0);
>> +
>> +	return tc358768_clear_error(priv);
>> +}
>> +
>> +static void tc358768_hw_enable(struct tc358768_priv *priv)
>> +{
>> +	int ret;
>> +
>> +	if (priv->enabled++ > 0)
>> +		return;
>> +
>> +	ret = regulator_bulk_enable(ARRAY_SIZE(priv->supplies), priv->supplies);
>> +	if (ret < 0)
>> +		dev_err(priv->dev, "error enabling regulators (%d)\n", ret);
>> +
>> +	if (priv->reset_gpio)
>> +		usleep_range(200, 300);
>> +
>> +	/*
>> +	 * The RESX is active low (GPIO_ACTIVE_LOW).
>> +	 * DEASSERT (value = 0) the reset_gpio to enable the chip
>> +	 */
>> +	gpiod_set_value_cansleep(priv->reset_gpio, 0);
>> +
>> +	/* wait for encoder clocks to stabilize */
>> +	usleep_range(1000, 2000);
>> +}
>> +
>> +static void tc358768_hw_disable(struct tc358768_priv *priv)
>> +{
>> +	int ret;
>> +
>> +	if (--priv->enabled != 0)
>> +		return;
>> +
>> +	/*
>> +	 * The RESX is active low (GPIO_ACTIVE_LOW).
>> +	 * ASSERT (value = 1) the reset_gpio to disable the chip
>> +	 */
>> +	gpiod_set_value_cansleep(priv->reset_gpio, 1);
>> +
>> +	ret = regulator_bulk_disable(ARRAY_SIZE(priv->supplies),
>> +				     priv->supplies);
>> +	if (ret < 0)
>> +		dev_err(priv->dev, "error disabling regulators (%d)\n", ret);
>> +}
>> +
>> +static u32 tc358768_pll_to_pclk(struct tc358768_priv *priv, u32 pll_clk)
>> +{
>> +	return (u32)div_u64((u64)pll_clk * priv->dsi_lanes, priv->pd_lines);
>> +}
>> +
>> +static u32 tc358768_pclk_to_pll(struct tc358768_priv *priv, u32 pclk)
>> +{
>> +	return (u32)div_u64((u64)pclk * priv->pd_lines, priv->dsi_lanes);
>> +}
>> +
>> +static int tc358768_calc_pll(struct tc358768_priv *priv,
>> +			     const struct drm_display_mode *mode,
>> +			     bool verify_only)
>> +{
>> +	const u32 frs_limits[] = {
>> +		1000000000,
>> +		500000000,
>> +		250000000,
>> +		125000000,
>> +		62500000
>> +	};
>> +	unsigned long refclk;
>> +	u32 prd, target_pll, i, max_pll, min_pll;
>> +	u32 frs, best_diff, best_pll, best_prd, best_fbd;
>> +
>> +	target_pll = tc358768_pclk_to_pll(priv, mode->clock * 1000);
>> +
>> +	/* pll_clk = RefClk * [(FBD + 1)/ (PRD + 1)] * [1 / (2^FRS)] */
>> +
>> +	for (i = 0; i < ARRAY_SIZE(frs_limits); i++)
>> +		if (target_pll >= frs_limits[i])
>> +			break;
>> +
>> +	if (i == ARRAY_SIZE(frs_limits) || i == 0)
>> +		return -EINVAL;
>> +
>> +	frs = i - 1;
>> +	max_pll = frs_limits[i - 1];
>> +	min_pll = frs_limits[i];
>> +
>> +	refclk = clk_get_rate(priv->refclk);
>> +
>> +	best_diff = UINT_MAX;
>> +	best_pll = 0;
>> +	best_prd = 0;
>> +	best_fbd = 0;
>> +
>> +	for (prd = 0; prd < 16; ++prd) {
>> +		u32 divisor = (prd + 1) * (1 << frs);
>> +		u32 fbd;
>> +
>> +		for (fbd = 0; fbd < 512; ++fbd) {
>> +			u32 pll, diff;
>> +
>> +			pll = (u32)div_u64((u64)refclk * (fbd + 1), divisor);
>> +
>> +			if (pll >= max_pll || pll < min_pll)
>> +				continue;
>> +
>> +			diff = max(pll, target_pll) - min(pll, target_pll);
>> +
>> +			if (diff < best_diff) {
>> +				best_diff = diff;
>> +				best_pll = pll;
>> +				best_prd = prd;
>> +				best_fbd = fbd;
>> +			}
>> +
>> +			if (best_diff == 0)
>> +				goto found;
> 
> 
> More optimal would be put above check inside block few lines above, at
> the cost of another indent, up to you.

True, but having the fourth indent level is a stretch, let mes see how
it looks and then I decide.

> 
>> +		}
>> +	}
>> +
>> +found:
>> +	if (best_diff == UINT_MAX) {
>> +		dev_err(priv->dev, "could not find suitable PLL setup\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (verify_only)
>> +		return 0;
>> +
>> +	priv->fbd = best_fbd;
>> +	priv->prd = best_prd;
>> +	priv->frs = frs;
>> +	priv->dsiclk = best_pll / 2;
>> +
>> +	return 0;
>> +}
>> +
>> +static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>> +				    struct mipi_dsi_device *dev)
>> +{
>> +	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
>> +	struct drm_bridge *bridge;
>> +	struct drm_panel *panel;
>> +	struct device_node *ep;
>> +	int ret;
>> +
>> +	if (dev->lanes > 4) {
>> +		dev_err(priv->dev, "unsupported number of data lanes(%u)\n",
>> +			dev->lanes);
>> +		return -EINVAL;
>> +	}
>> +
>> +	/*
>> +	 * tc358768 supports both Video and Pulse mode, but the driver only
>> +	 * implements Video (event) mode currently
>> +	 */
>> +	if (!(dev->mode_flags & MIPI_DSI_MODE_VIDEO)) {
>> +		dev_err(priv->dev, "Only MIPI_DSI_MODE_VIDEO is supported\n");
>> +		return -ENOTSUPP;
>> +	}
>> +
>> +	/*
>> +	 * tc358768 supports RGB888, RGB666, RGB666_PACKED and RGB565, but only
>> +	 * RGB888 is verified.
>> +	 */
>> +	if (dev->format != MIPI_DSI_FMT_RGB888) {
>> +		dev_warn(priv->dev, "Only MIPI_DSI_FMT_RGB888 tested!\n");
>> +		return -ENOTSUPP;
>> +	}
>> +
>> +	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0, &panel,
>> +					  &bridge);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (panel) {
>> +		bridge = drm_panel_bridge_add_typed(panel,
>> +						    DRM_MODE_CONNECTOR_DSI);
>> +		if (IS_ERR(bridge))
>> +			return PTR_ERR(bridge);
>> +	}
>> +
>> +	priv->output.dev = dev;
>> +	priv->output.bridge = bridge;
>> +	priv->output.panel = panel;
>> +
>> +	priv->dsi_lanes = dev->lanes;
>> +
>> +	/* get input ep (port0/endpoint0) */
>> +	ret = -EINVAL;
>> +	ep = of_graph_get_endpoint_by_regs(host->dev->of_node, 0, 0);
>> +	if (ep) {
>> +		ret = of_property_read_u32(ep, "data-lines", &priv->pd_lines);
>> +
>> +		of_node_put(ep);
>> +	}
>> +
>> +	if (ret)
>> +		priv->pd_lines = mipi_dsi_pixel_format_to_bpp(dev->format);
>> +
>> +	drm_bridge_add(&priv->bridge);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
>> +				    struct mipi_dsi_device *dev)
>> +{
>> +	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
>> +
>> +	drm_bridge_remove(&priv->bridge);
>> +	if (priv->output.panel)
>> +		drm_panel_bridge_remove(priv->output.bridge);
>> +
>> +	return 0;
>> +}
>> +
>> +static ssize_t tc358768_dsi_host_transfer(struct mipi_dsi_host *host,
>> +					  const struct mipi_dsi_msg *msg)
>> +{
>> +	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
>> +	struct mipi_dsi_packet packet;
>> +	int ret;
>> +
>> +	if (msg->rx_len) {
>> +		dev_warn(priv->dev, "MIPI rx is not supported\n");
>> +		return -ENOTSUPP;
>> +	}
>> +
>> +	if (msg->tx_len > 8) {
>> +		dev_warn(priv->dev, "Maximum 8 byte MIPI tx is supported\n");
>> +		return -ENOTSUPP;
>> +	}
>> +
>> +	ret = mipi_dsi_create_packet(&packet, msg);
>> +	if (ret)
>> +		return ret;
>> +
>> +	tc358768_hw_enable(priv);
> 
> 
> This looks suspicious, if you put tc358768_hw_enable here it means you
> are assuming hw can be disabled when transfer is requested, it means
> that after transfer the hardware will be disabled again, I do not think
> it is good thing - DSI bus is not designed for short transfers
> interleaved with hw enable/disable cycle, I guess it can be even harmful
> for downstream devices.
> 
> If this is workaround to allow downstream devices initialization in
> .pre_enable/.prepare callbacks I guess it can be solved properly by
> avoiding bridge->next callback chain, and calling downstream device
> opses directly, or we should think about more convenient solution.

I think I have seen a command sent before tc358768_bridge_enable() was
called, and this is the reason I have the refcounting of hw enabled
status, so commands after the bridge is enabled is not going to be
turned off.

If it is not valid to send commands before bridge.pre_enable() then it
is safe to remove the hw enable/disable from here.

I'll read more documentation and driver code to see how it is best done.


>> +
>> +	if (mipi_dsi_packet_format_is_short(msg->type)) {
>> +		tc358768_write(priv, TC358768_DSICMD_TYPE,
>> +			       (0x10 << 8) | (packet.header[0] & 0x3f));
>> +		tc358768_write(priv, TC358768_DSICMD_WC, 0);
>> +		tc358768_write(priv, TC358768_DSICMD_WD0,
>> +			       (packet.header[2] << 8) | packet.header[1]);
>> +	} else {
>> +		int i;
>> +
>> +		tc358768_write(priv, TC358768_DSICMD_TYPE,
>> +			       (0x40 << 8) | (packet.header[0] & 0x3f));
>> +		tc358768_write(priv, TC358768_DSICMD_WC, packet.payload_length);
>> +		for (i = 0; i < packet.payload_length; i += 2) {
>> +			u16 val = packet.payload[i];
>> +
>> +			if (i + 1 < packet.payload_length)
>> +				val |= packet.payload[i + 1] << 8;
>> +
>> +			tc358768_write(priv, TC358768_DSICMD_WD0 + i, val);
>> +		}
>> +	}
>> +
>> +	/* start transfer */
>> +	tc358768_write(priv, TC358768_DSICMD_TX, 1);
>> +
>> +	tc358768_hw_disable(priv);
>> +
>> +	return tc358768_clear_error(priv);
>> +}
>> +
>> +static const struct mipi_dsi_host_ops tc358768_dsi_host_ops = {
>> +	.attach = tc358768_dsi_host_attach,
>> +	.detach = tc358768_dsi_host_detach,
>> +	.transfer = tc358768_dsi_host_transfer,
>> +};
>> +
>> +static int tc358768_bridge_attach(struct drm_bridge *bridge)
>> +{
>> +	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
>> +
>> +	if (!drm_core_check_feature(bridge->dev, DRIVER_ATOMIC)) {
>> +		dev_err(priv->dev, "needs atomic updates support\n");
>> +		return -ENOTSUPP;
>> +	}
>> +
>> +	return drm_bridge_attach(bridge->encoder, priv->output.bridge, bridge);
>> +}
>> +
>> +static enum drm_mode_status
>> +tc358768_bridge_mode_valid(struct drm_bridge *bridge,
>> +			   const struct drm_display_mode *mode)
>> +{
>> +	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
>> +
>> +	if (tc358768_calc_pll(priv, mode, true))
>> +		return MODE_CLOCK_RANGE;
>> +
>> +	return MODE_OK;
>> +}
>> +
>> +static void tc358768_bridge_disable(struct drm_bridge *bridge)
>> +{
>> +	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
>> +	int ret;
>> +
>> +	/* set FrmStop */
>> +	tc358768_update_bits(priv, TC358768_PP_MISC, BIT(15), BIT(15));
>> +
>> +	/* wait at least for one frame */
>> +	msleep(50);
>> +
>> +	/* clear PP_en */
>> +	tc358768_update_bits(priv, TC358768_CONFCTL, BIT(6), 0);
>> +
>> +	/* set RstPtr */
>> +	tc358768_update_bits(priv, TC358768_PP_MISC, BIT(14), BIT(14));
>> +
>> +	ret = tc358768_clear_error(priv);
>> +	if (ret)
>> +		dev_warn(priv->dev, "Software disable failed: %d\n", ret);
>> +
>> +	tc358768_hw_disable(priv);
>> +}
>> +
>> +static int tc358768_setup_pll(struct tc358768_priv *priv,
>> +			      const struct drm_display_mode *mode)
>> +{
>> +	u32 fbd, prd, frs;
>> +	int ret;
>> +
>> +	ret = tc358768_calc_pll(priv, mode, false);
>> +	if (ret) {
>> +		dev_err(priv->dev, "PLL calculation failed: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	fbd = priv->fbd;
>> +	prd = priv->prd;
>> +	frs = priv->frs;
>> +
>> +	dev_dbg(priv->dev, "PLL: refclk %lu, fbd %u, prd %u, frs %u\n",
>> +		clk_get_rate(priv->refclk), fbd, prd, frs);
>> +	dev_dbg(priv->dev, "PLL: pll_clk: %u, DSIClk %u, DSIByteClk %u\n",
>> +		priv->dsiclk * 2, priv->dsiclk, priv->dsiclk / 4);
>> +	dev_dbg(priv->dev, "PLL: pclk %u (panel: %u)\n",
>> +		tc358768_pll_to_pclk(priv, priv->dsiclk * 2),
>> +		mode->clock * 1000);
>> +
>> +	/* PRD[15:12] FBD[8:0] */
>> +	tc358768_write(priv, TC358768_PLLCTL0, (prd << 12) | fbd);
>> +
>> +	/* FRS[11:10] LBWS[9:8] CKEN[4] RESETB[1] EN[0] */
>> +	tc358768_write(priv, TC358768_PLLCTL1,
>> +		       (frs << 10) | (0x2 << 8) | BIT(1) | BIT(0));
>> +
>> +	/* wait for lock */
>> +	usleep_range(1000, 2000);
>> +
>> +	/* FRS[11:10] LBWS[9:8] CKEN[4] PLL_CKEN[4] RESETB[1] EN[0] */
>> +	tc358768_write(priv, TC358768_PLLCTL1,
>> +		       (frs << 10) | (0x2 << 8) | BIT(4) | BIT(1) | BIT(0));
>> +
>> +	return tc358768_clear_error(priv);
>> +}
>> +
>> +#define TC358768_PRECISION	1000
>> +static u32 tc358768_ns_to_cnt(u32 ns, u32 period_nsk)
>> +{
>> +	return (ns * TC358768_PRECISION + period_nsk) / period_nsk;
>> +}
>> +
>> +static u32 tc358768_to_ns(u32 nsk)
>> +{
>> +	return (nsk / TC358768_PRECISION);
>> +}
>> +
>> +static void tc358768_bridge_enable(struct drm_bridge *bridge)
>> +{
>> +	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
>> +	struct mipi_dsi_device *dsi_dev = priv->output.dev;
>> +	u32 val, val2, lptxcnt, hact, data_type;
>> +	const struct drm_display_mode *mode;
>> +	u32 dsibclk_nsk, dsiclk_nsk, ui_nsk, phy_delay_nsk;
>> +	u32 dsiclk, dsibclk;
>> +	int ret, i;
>> +
>> +	tc358768_hw_enable(priv);
>> +
>> +	ret = tc358768_sw_reset(priv);
>> +	if (ret) {
>> +		dev_err(priv->dev, "Software reset failed: %d\n", ret);
>> +		return;
>> +	}
> 
> 
> I think above code (maybe more) should go to pre_enable, bridges should
> follow quite well established practices for panels [1], ie
> bridge.pre_enable should do similar things as panel.prepare, etc,
> 
> this can be separated if user requiring it appears.
> 
> https://dri.freedesktop.org/docs/drm/gpu/drm-kms-helpers.html?highlight=drm_panel_funcs#c.drm_panel_funcs

Thanks for the pointer, I'll rework this to comply with the 'standard'

>> +
>> +	mode = &bridge->encoder->crtc->state->adjusted_mode;
>> +	ret = tc358768_setup_pll(priv, mode);
>> +	if (ret) {
>> +		dev_err(priv->dev, "PLL setup failed: %d\n", ret);
>> +		return;
>> +	}
>> +
>> +	dsiclk = priv->dsiclk;
>> +	dsibclk = dsiclk / 4;
>> +
>> +	/* Data Format Control Register */
>> +	val = BIT(2) | BIT(1) | BIT(0); /* rdswap_en | dsitx_en | txdt_en */
>> +	switch (dsi_dev->format) {
>> +	case MIPI_DSI_FMT_RGB888:
>> +		val |= (0x3 << 4);
>> +		hact = mode->hdisplay * 3;
>> +		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_24;
>> +		break;
>> +	case MIPI_DSI_FMT_RGB666:
>> +		val |= (0x4 << 4);
>> +		hact = mode->hdisplay * 3;
>> +		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_18;
>> +		break;
>> +
>> +	case MIPI_DSI_FMT_RGB666_PACKED:
>> +		val |= (0x4 << 4) | BIT(3);
>> +		hact = mode->hdisplay * 18 / 8;
>> +		data_type = MIPI_DSI_PIXEL_STREAM_3BYTE_18;
>> +		break;
>> +
>> +	case MIPI_DSI_FMT_RGB565:
>> +		val |= (0x5 << 4);
>> +		hact = mode->hdisplay * 2;
>> +		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_16;
>> +		break;
>> +	default:
>> +		dev_err(priv->dev, "Invalid data format (%u)\n",
>> +			dsi_dev->format);
>> +		return;
>> +	}
>> +
>> +	/* VSDly[9:0] */
>> +	tc358768_write(priv, TC358768_VSDLY, 1);
>> +
>> +	tc358768_write(priv, TC358768_DATAFMT, val);
>> +	tc358768_write(priv, TC358768_DSITX_DT, data_type);
>> +
>> +	/* Enable D-PHY (HiZ->LP11) */
>> +	tc358768_write(priv, TC358768_CLW_CNTRL, 0x0000);
>> +	/* Enable lanes */
>> +	for (i = 0; i < dsi_dev->lanes; i++)
>> +		tc358768_write(priv, TC358768_D0W_CNTRL + i * 4, 0x0000);
>> +
>> +	/* DSI Timings */
>> +	dsibclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION,
>> +				  dsibclk);
>> +	dsiclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION, dsiclk);
>> +	ui_nsk = dsiclk_nsk / 2;
>> +	phy_delay_nsk = dsibclk_nsk + 2 * dsiclk_nsk;
>> +	dev_dbg(priv->dev, "dsiclk_nsk: %u\n", dsiclk_nsk);
>> +	dev_dbg(priv->dev, "ui_nsk: %u\n", ui_nsk);
>> +	dev_dbg(priv->dev, "dsibclk_nsk: %u\n", dsibclk_nsk);
>> +	dev_dbg(priv->dev, "phy_delay_nsk: %u\n", phy_delay_nsk);
>> +
>> +	/* LP11 > 100us for D-PHY Rx Init */
>> +	val = tc358768_ns_to_cnt(100 * 1000, dsibclk_nsk) - 1;
>> +	dev_dbg(priv->dev, "LINEINITCNT: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_LINEINITCNT, val);
>> +
>> +	/* LPTimeCnt > 50ns */
>> +	val = tc358768_ns_to_cnt(50, dsibclk_nsk) - 1;
>> +	lptxcnt = val;
>> +	dev_dbg(priv->dev, "LPTXTIMECNT: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_LPTXTIMECNT, val);
>> +
>> +	/* 38ns < TCLK_PREPARE < 95ns */
>> +	val = tc358768_ns_to_cnt(65, dsibclk_nsk) - 1;
>> +	/* TCLK_PREPARE > 300ns */
>> +	val2 = tc358768_ns_to_cnt(300 + tc358768_to_ns(3 * ui_nsk),
>> +				  dsibclk_nsk);
>> +	val |= (val2 - tc358768_to_ns(phy_delay_nsk - dsibclk_nsk)) << 8;
>> +	dev_dbg(priv->dev, "TCLK_HEADERCNT: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_TCLK_HEADERCNT, val);
>> +
>> +	/* TCLK_TRAIL > 60ns + 3*UI */
>> +	val = 60 + tc358768_to_ns(3 * ui_nsk);
>> +	val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 5;
>> +	dev_dbg(priv->dev, "TCLK_TRAILCNT: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_TCLK_TRAILCNT, val);
>> +
>> +	/* 40ns + 4*UI < THS_PREPARE < 85ns + 6*UI */
>> +	val = 50 + tc358768_to_ns(4 * ui_nsk);
>> +	val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 1;
>> +	/* THS_ZERO > 145ns + 10*UI */
>> +	val2 = tc358768_ns_to_cnt(145 - tc358768_to_ns(ui_nsk), dsibclk_nsk);
>> +	val |= (val2 - tc358768_to_ns(phy_delay_nsk)) << 8;
>> +	dev_dbg(priv->dev, "THS_HEADERCNT: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_THS_HEADERCNT, val);
>> +
>> +	/* TWAKEUP > 1ms in lptxcnt steps */
>> +	val = tc358768_ns_to_cnt(1020000, dsibclk_nsk);
>> +	val = val / (lptxcnt + 1) - 1;
>> +	dev_dbg(priv->dev, "TWAKEUP: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_TWAKEUP, val);
>> +
>> +	/* TCLK_POSTCNT > 60ns + 52*UI */
>> +	val = tc358768_ns_to_cnt(60 + tc358768_to_ns(52 * ui_nsk),
>> +				 dsibclk_nsk) - 3;
>> +	dev_dbg(priv->dev, "TCLK_POSTCNT: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_TCLK_POSTCNT, val);
>> +
>> +	/* 60ns + 4*UI < THS_PREPARE < 105ns + 12*UI */
>> +	val = tc358768_ns_to_cnt(60 + tc358768_to_ns(15 * ui_nsk),
>> +				 dsibclk_nsk) - 5;
>> +	dev_dbg(priv->dev, "THS_TRAILCNT: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_THS_TRAILCNT, val);
>> +
>> +	val = BIT(0);
>> +	for (i = 0; i < dsi_dev->lanes; i++)
>> +		val |= BIT(i + 1);
>> +	tc358768_write(priv, TC358768_HSTXVREGEN, val);
>> +
>> +	if (!(dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
>> +		tc358768_write(priv, TC358768_TXOPTIONCNTRL, 0x1);
>> +
>> +	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
>> +	val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
>> +	val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 1;
>> +	val2 = tc358768_ns_to_cnt(tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk),
>> +				  dsibclk_nsk) - 2;
>> +	val |= val2 << 16;
>> +	dev_dbg(priv->dev, "BTACNTRL1: 0x%x\n", val);
>> +	tc358768_write(priv, TC358768_BTACNTRL1, val);
>> +
>> +	/* START[0] */
>> +	tc358768_write(priv, TC358768_STARTCNTRL, 1);
>> +
>> +	/* Set event mode */
>> +	tc358768_write(priv, TC358768_DSI_EVENT, 1);
>> +
>> +	/* vsw (+ vbp) */
>> +	tc358768_write(priv, TC358768_DSI_VSW,
>> +		       mode->vtotal - mode->vsync_start);
>> +	/* vbp (not used in event mode) */
>> +	tc358768_write(priv, TC358768_DSI_VBPR, 0);
>> +	/* vact */
>> +	tc358768_write(priv, TC358768_DSI_VACT, mode->vdisplay);
>> +
>> +	/* (hsw + hbp) * byteclk * ndl / pclk */
>> +	val = (u32)div_u64((mode->htotal - mode->hsync_start) *
>> +			   ((u64)priv->dsiclk / 4) * priv->dsi_lanes,
>> +			   mode->clock * 1000);
>> +	tc358768_write(priv, TC358768_DSI_HSW, val);
>> +	/* hbp (not used in event mode) */
>> +	tc358768_write(priv, TC358768_DSI_HBPR, 0);
>> +	/* hact (bytes) */
>> +	tc358768_write(priv, TC358768_DSI_HACT, hact);
>> +
>> +	/* VSYNC polarity */
>> +	if (!(mode->flags & DRM_MODE_FLAG_NVSYNC))
>> +		tc358768_update_bits(priv, TC358768_CONFCTL, BIT(5), BIT(5));
>> +	/* HSYNC polarity */
>> +	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
>> +		tc358768_update_bits(priv, TC358768_PP_MISC, BIT(0), BIT(0));
>> +
>> +	/* Start DSI Tx */
>> +	tc358768_write(priv, TC358768_DSI_START, 0x1);
>> +
>> +	/* Configure DSI_Control register */
>> +	val = (6 << 29) | (0x3 << 24); /* CLEAR, DSI_Control */
>> +	val |= BIT(7) | BIT(5) | 0x3 << 1 | BIT(0);
>> +	tc358768_write(priv, TC358768_DSI_CONFW, val);
>> +
>> +	val = (5 << 29) | (0x3 << 24); /* SET, DSI_Control */
>> +	if (!(dsi_dev->mode_flags & MIPI_DSI_MODE_LPM))
>> +		val |= BIT(7);
>> +	if (!(dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
>> +		val |= BIT(5);
>> +	val |= (dsi_dev->lanes - 1) << 1;
>> +	if (dsi_dev->mode_flags & MIPI_DSI_MODE_EOT_PACKET)
>> +		val |= BIT(0);
>> +	tc358768_write(priv, TC358768_DSI_CONFW, val);
>> +
>> +	val = (6 << 29) | (0x3 << 24); /* CLEAR, DSI_Control */
>> +	val |= 0x8000; /* DSI mode */
>> +	tc358768_write(priv, TC358768_DSI_CONFW, val);
>> +
>> +	/* clear FrmStop and RstPtr */
>> +	tc358768_update_bits(priv, TC358768_PP_MISC, 0x3 << 14, 0);
>> +
>> +	/* set PP_en */
>> +	tc358768_update_bits(priv, TC358768_CONFCTL, BIT(6), BIT(6));
>> +
>> +	ret = tc358768_clear_error(priv);
>> +	if (ret) {
>> +		dev_err(priv->dev, "Bridge enable failed: %d\n", ret);
>> +		tc358768_bridge_disable(bridge);
>> +	}
>> +}
>> +
>> +static const struct drm_bridge_funcs tc358768_bridge_funcs = {
>> +	.attach = tc358768_bridge_attach,
>> +	.mode_valid = tc358768_bridge_mode_valid,
>> +	.disable = tc358768_bridge_disable,
>> +	.enable = tc358768_bridge_enable,
>> +};
>> +
>> +static const struct drm_bridge_timings default_tc358768_timings = {
>> +	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE
>> +		 | DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE
>> +		 | DRM_BUS_FLAG_DE_HIGH,
>> +};
>> +
>> +static bool tc358768_is_reserved_reg(unsigned int reg)
>> +{
>> +	switch (reg) {
>> +	case 0x114 ... 0x13f:
>> +	case 0x200:
>> +	case 0x20c:
>> +	case 0x400 ... 0x408:
>> +	case 0x41c ... 0x42f:
>> +		return true;
>> +	default:
>> +		return false;
>> +	}
>> +}
>> +
>> +static bool tc358768_writeable_reg(struct device *dev, unsigned int reg)
>> +{
>> +	if (tc358768_is_reserved_reg(reg))
>> +		return false;
>> +
>> +	switch (reg) {
>> +	case TC358768_CHIPID:
>> +	case TC358768_FIFOSTATUS:
>> +	case TC358768_DSITXSTATUS ... (TC358768_DSITXSTATUS + 2):
>> +	case TC358768_DSI_CONTROL ... (TC358768_DSI_INT_ENA + 2):
>> +	case TC358768_DSICMD_RDFIFO ... (TC358768_DSI_ERR_HALT + 2):
>> +		return false;
>> +	default:
>> +		return true;
>> +	}
>> +}
>> +
>> +static bool tc358768_readable_reg(struct device *dev, unsigned int reg)
>> +{
>> +	if (tc358768_is_reserved_reg(reg))
>> +		return false;
>> +
>> +	switch (reg) {
>> +	case TC358768_STARTCNTRL:
>> +	case TC358768_DSI_CONFW ... (TC358768_DSI_CONFW + 2):
>> +	case TC358768_DSI_INT_CLR ... (TC358768_DSI_INT_CLR + 2):
>> +	case TC358768_DSI_START ... (TC358768_DSI_START + 2):
>> +	case TC358768_DBG_DATA:
>> +		return false;
>> +	default:
>> +		return true;
>> +	}
>> +}
>> +
>> +static const struct regmap_config tc358768_regmap_config = {
>> +	.name = "tc358768",
>> +	.reg_bits = 16,
>> +	.val_bits = 16,
>> +	.max_register = TC358768_DSI_HACT,
>> +	.cache_type = REGCACHE_NONE,
>> +	.writeable_reg = tc358768_writeable_reg,
>> +	.readable_reg = tc358768_readable_reg,
>> +	.reg_format_endian = REGMAP_ENDIAN_BIG,
>> +	.val_format_endian = REGMAP_ENDIAN_BIG,
>> +};
>> +
>> +static const struct i2c_device_id tc358768_i2c_ids[] = {
>> +	{ "tc358768", 0 },
>> +	{ "tc358778", 0 },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, tc358768_i2c_ids);
>> +
>> +static const struct of_device_id tc358768_of_ids[] = {
>> +	{ .compatible = "toshiba,tc358768", },
>> +	{ .compatible = "toshiba,tc358778", },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(of, tc358768_of_ids);
>> +
>> +static int tc358768_get_regulators(struct tc358768_priv *priv)
>> +{
>> +	int i, ret;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(priv->supplies); ++i)
>> +		priv->supplies[i].supply = tc358768_supplies[i];
>> +
>> +	ret = devm_regulator_bulk_get(priv->dev, ARRAY_SIZE(priv->supplies),
>> +				      priv->supplies);
>> +	if (ret < 0)
>> +		dev_err(priv->dev, "failed to get regulators: %d\n", ret);
>> +
>> +	return ret;
>> +}
>> +
>> +static int tc358768_i2c_probe(struct i2c_client *client,
>> +			      const struct i2c_device_id *id)
>> +{
>> +	struct tc358768_priv *priv;
>> +	struct device *dev = &client->dev;
>> +	struct device_node *np = dev->of_node;
>> +	int ret;
>> +
>> +	if (!np)
>> +		return -ENODEV;
>> +
>> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	dev_set_drvdata(dev, priv);
>> +	priv->dev = dev;
>> +
>> +	ret = tc358768_get_regulators(priv);
>> +	if (ret)
>> +		return ret;
>> +
>> +	priv->refclk = devm_clk_get(dev, "refclk");
>> +	if (IS_ERR(priv->refclk))
>> +		return PTR_ERR(priv->refclk);
>> +
>> +	/*
>> +	 * RESX is low active, to disable tc358768 initially (keep in reset)
>> +	 * the gpio line must be LOW. This is the ASSERTED state of
>> +	 * GPIO_ACTIVE_LOW (GPIOD_OUT_HIGH == ASSERTED).
>> +	 */
>> +	priv->reset_gpio  = devm_gpiod_get_optional(dev, "reset",
>> +						    GPIOD_OUT_HIGH);
>> +	if (IS_ERR(priv->reset_gpio))
>> +		return PTR_ERR(priv->reset_gpio);
>> +
>> +	priv->regmap = devm_regmap_init_i2c(client, &tc358768_regmap_config);
>> +	if (IS_ERR(priv->regmap)) {
>> +		dev_err(dev, "Failed to init regmap\n");
>> +		return PTR_ERR(priv->regmap);
>> +	}
>> +
>> +	priv->dsi_host.dev = dev;
>> +	priv->dsi_host.ops = &tc358768_dsi_host_ops;
>> +
>> +	priv->bridge.funcs = &tc358768_bridge_funcs;
>> +	priv->bridge.timings = &default_tc358768_timings;
>> +	priv->bridge.of_node = np;
>> +
>> +	i2c_set_clientdata(client, priv);
>> +
>> +	ret = mipi_dsi_host_register(&priv->dsi_host);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return 0;
> 
> 
> It could be replaced by:
> 
> ÂÂÂ return mipi_dsi_host_register(&priv->dsi_host);
> 
> Matter of taste, up to you.

Sure, I'm not sure why I left it like this to be honest.

> 
> Overall the driver is in good shape, except hw_enable refcounting, which
> I hope we will clarify quickly.

I can take a look at this on Monday, most likely I can send v3 on the
afternoon.

Thank you,
- PÃter

> 
> 
> Regards
> 
> Andrzej
> 
> 
>> +}
>> +
>> +static int tc358768_i2c_remove(struct i2c_client *client)
>> +{
>> +	struct tc358768_priv *priv = i2c_get_clientdata(client);
>> +
>> +	mipi_dsi_host_unregister(&priv->dsi_host);
>> +
>> +	return 0;
>> +}
>> +
>> +static struct i2c_driver tc358768_driver = {
>> +	.driver = {
>> +		.name = "tc358768",
>> +		.of_match_table = tc358768_of_ids,
>> +	},
>> +	.id_table = tc358768_i2c_ids,
>> +	.probe = tc358768_i2c_probe,
>> +	.remove	= tc358768_i2c_remove,
>> +};
>> +module_i2c_driver(tc358768_driver);
>> +
>> +MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@xxxxxx>");
>> +MODULE_DESCRIPTION("TC358768AXBG/TC358778XBG DSI bridge");
>> +MODULE_LICENSE("GPL v2");
> 
> 

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