From: Robert Chiras robert.chiras@nxp.com
This patch adds support for a new clock 'video_pll' in order to better set the video_pll clock to a clock-rate that satisfies a mode's clock. The video PLL, on i.MX8MQ, can drive both DC pixel-clock and DSI phy_ref clock. When used with a bridge that can drive multiple modes, like a DSI to HDMI bridge, the DSI can't be statically configured for a specific mode in the DTS file. So, this patch adds access to the video PLL inside the DSI driver, so that modes can be filtered-out if the required combination of phy_ref and pixel-clock can't be achieved using the video PLL.
Signed-off-by: Robert Chiras robert.chiras@nxp.com --- drivers/gpu/drm/bridge/nwl-dsi.c | 318 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 313 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c index ce94f79..1228466 100644 --- a/drivers/gpu/drm/bridge/nwl-dsi.c +++ b/drivers/gpu/drm/bridge/nwl-dsi.c @@ -39,6 +39,20 @@
#define NWL_DSI_MIPI_FIFO_TIMEOUT msecs_to_jiffies(500)
+/* Maximum Video PLL frequency: 1.2GHz */ +#define MAX_PLL_FREQ 1200000000 + +#define MBPS(x) ((x) * 1000000) +#define MIN_PHY_RATE MBPS(24) +#define MAX_PHY_RATE MBPS(30) + +/* Possible valid PHY reference clock rates*/ +static u32 phyref_rates[] = { + 27000000, + 25000000, + 24000000, +}; + enum transfer_direction { DSI_PACKET_SEND, DSI_PACKET_RECEIVE, @@ -67,6 +81,17 @@ struct nwl_dsi_transfer { size_t rx_len; /* in bytes */ };
+struct mode_config { + int clock; + int crtc_clock; + unsigned int lanes; + unsigned long bitclock; + unsigned long phy_rates[3]; + unsigned long pll_rates[3]; + int phy_rate_idx; + struct list_head list; +}; + struct nwl_dsi { struct drm_bridge bridge; struct mipi_dsi_host dsi_host; @@ -101,6 +126,7 @@ struct nwl_dsi { struct clk *rx_esc_clk; struct clk *tx_esc_clk; struct clk *core_clk; + struct clk *pll_clk; /* * hardware bug: the i.MX8MQ needs this clock on during reset * even when not using LCDIF. @@ -115,6 +141,7 @@ struct nwl_dsi { int error;
struct nwl_dsi_transfer *xfer; + struct list_head valid_modes; };
static const struct regmap_config nwl_dsi_regmap_config = { @@ -778,6 +805,207 @@ static void nwl_dsi_bridge_disable(struct drm_bridge *bridge) pm_runtime_put(dsi->dev); }
+static unsigned long nwl_dsi_get_bit_clock(struct nwl_dsi *dsi, + unsigned long pixclock, u32 lanes) +{ + int bpp; + + if (lanes < 1 || lanes > 4) + return 0; + + bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); + + return (pixclock * bpp) / lanes; +} + +/* + * Utility function to calculate least commom multiple, using an improved + * version of the Euclidean algorithm for greatest common factor. + */ +static unsigned long nwl_dsi_get_lcm(unsigned long a, unsigned long b) +{ + u32 gcf = 0; /* greatest common factor */ + unsigned long tmp_a = a; + unsigned long tmp_b = b; + + if (!a || !b) + return 0; + + while (tmp_a % tmp_b) { + gcf = tmp_a % tmp_b; + tmp_a = tmp_b; + tmp_b = gcf; + } + + if (!gcf) + return a; + + return ((unsigned long long)a * b) / gcf; +} + +/* + * This function tries to adjust the crtc_clock for a DSI device in such a way + * that the video pll will be able to satisfy both Display Controller pixel + * clock (feeding out DPI interface) and our input phy_ref clock. + */ +static void nwl_dsi_setup_pll_config(struct mode_config *config) +{ + unsigned long pll_rate; + int div; + size_t i, num_rates = ARRAY_SIZE(config->phy_rates); + + config->crtc_clock = 0; + + for (i = 0; i < num_rates; i++) { + int crtc_clock; + + if (!config->phy_rates[i]) + break; + /* + * First, we need to check if phy_ref can actually be obtained + * from pixel clock. To do this, we check their lowest common + * multiple, which has to be in PLL range. + */ + pll_rate = nwl_dsi_get_lcm(config->clock, config->phy_rates[i]); + if (pll_rate > MAX_PLL_FREQ) { + /* Drop pll_rate to a realistic value */ + while (pll_rate > MAX_PLL_FREQ) + pll_rate >>= 1; + /* Make sure pll_rate can provide phy_ref rate */ + div = DIV_ROUND_UP(pll_rate, config->phy_rates[i]); + pll_rate = config->phy_rates[i] * div; + } else { + /* + * Increase the pll rate to highest possible rate for + * better accuracy. + */ + while (pll_rate <= MAX_PLL_FREQ) + pll_rate <<= 1; + pll_rate >>= 1; + } + + /* + * Next, we need to tweak the pll_rate to a value that can also + * satisfy the crtc_clock. + */ + div = DIV_ROUND_CLOSEST(pll_rate, config->clock); + if (lvl) + pll_rate -= config->phy_rates[i] * lvl; + crtc_clock = pll_rate / div; + config->pll_rates[i] = pll_rate; + + /* + * Pick a crtc_clock which is closest to pixel clock. + * Also, make sure that the pixel clock is a multiply of + * 50Hz. + */ + if (!(crtc_clock % 50) && + abs(config->clock - crtc_clock) < + abs(config->clock - config->crtc_clock)) { + config->crtc_clock = crtc_clock; + config->phy_rate_idx = i; + } + } +} + + +/* + * This function will try the required phy speed for current mode + * If the phy speed can be achieved, the phy will save the speed + * configuration + */ +static struct mode_config *nwl_dsi_mode_probe(struct nwl_dsi *dsi, + const struct drm_display_mode *mode) +{ + struct device *dev = dsi->dev; + struct mode_config *config; + union phy_configure_opts phy_opts; + unsigned long clock = mode->clock * 1000; + unsigned long bit_clk = 0; + unsigned long phy_rates[3] = {0}; + int match_rates = 0; + u32 lanes = dsi->lanes; + size_t i = 0, num_rates = ARRAY_SIZE(phyref_rates); + + list_for_each_entry(config, &dsi->valid_modes, list) + if (config->clock == clock) + return config; + + phy_mipi_dphy_get_default_config(clock, + mipi_dsi_pixel_format_to_bpp(dsi->format), + lanes, &phy_opts.mipi_dphy); + phy_opts.mipi_dphy.lp_clk_rate = clk_get_rate(dsi->tx_esc_clk); + + while (i < num_rates) { + int ret; + + bit_clk = nwl_dsi_get_bit_clock(dsi, clock, lanes); + + clk_set_rate(dsi->pll_clk, phyref_rates[i] * 32); + clk_set_rate(dsi->phy_ref_clk, phyref_rates[i]); + ret = phy_validate(dsi->phy, PHY_MODE_MIPI_DPHY, 0, &phy_opts); + + /* Pick the non-failing rate, and search for more */ + if (!ret) { + phy_rates[match_rates++] = phyref_rates[i++]; + continue; + } + + if (match_rates) + break; + + /* Reached the end of phyref_rates, try another lane config */ + if ((i++ == num_rates - 1) && (--lanes > 2)) { + i = 0; + continue; + } + } + + /* + * Try swinging between min and max pll rates and see what rate (in terms + * of kHz) we can custom use to get the required bit-clock. + */ + if (!match_rates) { + int min_div, max_div; + int bit_clk_khz; + + lanes = dsi->lanes; + bit_clk = nwl_dsi_get_bit_clock(dsi, clock, lanes); + + min_div = DIV_ROUND_UP(bit_clk, MAX_PHY_RATE); + max_div = DIV_ROUND_DOWN_ULL(bit_clk, MIN_PHY_RATE); + bit_clk_khz = bit_clk / 1000; + + for (i = max_div; i > min_div; i--) { + if (!(bit_clk_khz % i)) { + phy_rates[0] = bit_clk / i; + match_rates = 1; + break; + } + } + } + + if (!match_rates) { + DRM_DEV_DEBUG_DRIVER(dev, + "Cannot setup PHY for mode: %ux%u @%d kHz\n", + mode->hdisplay, + mode->vdisplay, + mode->clock); + + return NULL; + } + + config = devm_kzalloc(dsi->dev, sizeof(struct mode_config), GFP_KERNEL); + config->clock = clock; + config->lanes = lanes; + config->bitclock = bit_clk; + memcpy(&config->phy_rates, &phy_rates, sizeof(phy_rates)); + list_add(&config->list, &dsi->valid_modes); + + return config; +} + + static int nwl_dsi_get_dphy_params(struct nwl_dsi *dsi, const struct drm_display_mode *mode, union phy_configure_opts *phy_opts) @@ -809,6 +1037,38 @@ static bool nwl_dsi_bridge_mode_fixup(struct drm_bridge *bridge, const struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode) { + struct nwl_dsi *dsi = bridge_to_dsi(bridge); + struct mode_config *config; + unsigned long pll_rate; + + DRM_DEV_DEBUG_DRIVER(dsi->dev, "Fixup mode:\n"); + drm_mode_debug_printmodeline(adjusted_mode); + + config = nwl_dsi_mode_probe(dsi, adjusted_mode); + if (!config) + return false; + + DRM_DEV_DEBUG_DRIVER(dsi->dev, "lanes=%u, data_rate=%lu\n", + config->lanes, config->bitclock); + if (config->lanes < 2 || config->lanes > 4) + return false; + + /* Max data rate for this controller is 1.5Gbps */ + if (config->bitclock > 1500000000) + return false; + + pll_rate = config->pll_rates[config->phy_rate_idx]; + if (dsi->pll_clk && pll_rate) { + clk_set_rate(dsi->pll_clk, pll_rate); + DRM_DEV_DEBUG_DRIVER(dsi->dev, + "Video pll rate: %lu (actual: %lu)", + pll_rate, clk_get_rate(dsi->pll_clk)); + } + /* Update the crtc_clock to be used by display controller */ + if (config->crtc_clock) + adjusted_mode->crtc_clock = config->crtc_clock / 1000; + + /* At least LCDIF + NWL needs active high sync */ adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC); adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC); @@ -822,14 +1082,29 @@ nwl_dsi_bridge_mode_valid(struct drm_bridge *bridge, const struct drm_display_mode *mode) { struct nwl_dsi *dsi = bridge_to_dsi(bridge); - int bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); + struct mode_config *config; + unsigned long pll_rate; + int bit_rate;
- if (mode->clock * bpp > 15000000 * dsi->lanes) + bit_rate = nwl_dsi_get_bit_clock(dsi, mode->clock * 1000, dsi->lanes); + + DRM_DEV_DEBUG_DRIVER(dsi->dev, "Validating mode:"); + drm_mode_debug_printmodeline(mode); + + if (bit_rate > MBPS(1500)) return MODE_CLOCK_HIGH;
- if (mode->clock * bpp < 80000 * dsi->lanes) + if (bit_rate < MBPS(80)) return MODE_CLOCK_LOW;
+ config = nwl_dsi_mode_probe(dsi, mode); + if (!config) + return MODE_NOCLOCK; + + pll_rate = config->pll_rates[config->phy_rate_idx]; + if (dsi->pll_clk && !pll_rate) + nwl_dsi_setup_pll_config(config); + return MODE_OK; }
@@ -842,8 +1117,22 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge, struct device *dev = dsi->dev; union phy_configure_opts new_cfg; unsigned long phy_ref_rate; + struct mode_config *config; int ret;
+ DRM_DEV_DEBUG_DRIVER(dsi->dev, "Setting mode:\n"); + drm_mode_debug_printmodeline(adjusted_mode); + + config = nwl_dsi_mode_probe(dsi, adjusted_mode); + /* New mode? This should NOT happen */ + if (!config) { + DRM_DEV_ERROR(dsi->dev, "Unsupported mode provided:\n"); + drm_mode_debug_printmodeline(adjusted_mode); + return; + } + + phy_ref_rate = config->phy_rates[config->phy_rate_idx]; + clk_set_rate(dsi->phy_ref_clk, phy_ref_rate); ret = nwl_dsi_get_dphy_params(dsi, adjusted_mode, &new_cfg); if (ret < 0) return; @@ -855,8 +1144,10 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge, if (new_cfg.mipi_dphy.hs_clk_rate == dsi->phy_cfg.mipi_dphy.hs_clk_rate) return;
- phy_ref_rate = clk_get_rate(dsi->phy_ref_clk); - DRM_DEV_DEBUG_DRIVER(dev, "PHY at ref rate: %lu\n", phy_ref_rate); + DRM_DEV_DEBUG_DRIVER(dev, + "PHY at ref rate: %lu (actual: %lu)\n", + phy_ref_rate, clk_get_rate(dsi->phy_ref_clk)); + /* Save the new desired phy config */ memcpy(&dsi->phy_cfg, &new_cfg, sizeof(new_cfg));
@@ -1014,6 +1305,12 @@ static int nwl_dsi_parse_dt(struct nwl_dsi *dsi) } dsi->tx_esc_clk = clk;
+ /* The video_pll clock is optional */ + clk = devm_clk_get(dsi->dev, "video_pll"); + if (!IS_ERR(clk)) + dsi->pll_clk = clk; + + dsi->mux = devm_mux_control_get(dsi->dev, NULL); if (IS_ERR(dsi->mux)) { ret = PTR_ERR(dsi->mux); @@ -1066,6 +1363,9 @@ static int nwl_dsi_parse_dt(struct nwl_dsi *dsi) PTR_ERR(dsi->rst_dpi)); return PTR_ERR(dsi->rst_dpi); } + + INIT_LIST_HEAD(&dsi->valid_modes); + return 0; }
@@ -1184,6 +1484,14 @@ static int nwl_dsi_probe(struct platform_device *pdev) static int nwl_dsi_remove(struct platform_device *pdev) { struct nwl_dsi *dsi = platform_get_drvdata(pdev); + struct mode_config *config; + struct list_head *pos, *tmp; + + list_for_each_safe(pos, tmp, &dsi->valid_modes) { + config = list_entry(pos, struct mode_config, list); + list_del(pos); + devm_kfree(dsi->dev, config); + }
nwl_dsi_deselect_input(dsi); mipi_dsi_host_unregister(&dsi->dsi_host);