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9a8406ba1a
The D-PHY specification (v1.2) explicitly mentions that the T-CLK-PRE
parameter's unit is Unit Interval(UI) and the minimum value is 8. Also,
kernel doc of the 'clk_pre' member of struct phy_configure_opts_mipi_dphy
mentions that it should be in UI. However, the dphy core driver wrongly
sets 'clk_pre' to 8000, which seems to hint that it's in picoseconds.
So, let's fix the dphy core driver to correctly reflect the T-CLK-PRE
parameter's minimum value according to the D-PHY specification.
I'm assuming that all impacted custom drivers shall program values in
TxByteClkHS cycles into hardware for the T-CLK-PRE parameter. The D-PHY
specification mentions that the frequency of TxByteClkHS is exactly 1/8
the High-Speed(HS) bit rate(each HS bit consumes one UI). So, relevant
custom driver code is changed to program those values as
DIV_ROUND_UP(cfg->clk_pre, BITS_PER_BYTE), then.
Note that I've only tested the patch with RM67191 DSI panel on i.MX8mq EVK.
Help is needed to test with other i.MX8mq, Meson and Rockchip platforms,
as I don't have the hardwares.
Fixes: 2ed869990e ("phy: Add MIPI D-PHY configuration options")
Tested-by: Liu Ying <victor.liu@nxp.com> # RM67191 DSI panel on i.MX8mq EVK
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> # for phy-meson-axg-mipi-dphy.c
Tested-by: Neil Armstrong <narmstrong@baylibre.com> # for phy-meson-axg-mipi-dphy.c
Tested-by: Guido Günther <agx@sigxcpu.org> # Librem 5 (imx8mq) with it's rather picky panel
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20220124024007.1465018-1-victor.liu@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
165 lines
3.7 KiB
C
165 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2013 NVIDIA Corporation
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* Copyright (C) 2018 Cadence Design Systems Inc.
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*/
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#include <linux/errno.h>
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/time64.h>
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#include <linux/phy/phy.h>
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#include <linux/phy/phy-mipi-dphy.h>
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/*
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* Minimum D-PHY timings based on MIPI D-PHY specification. Derived
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* from the valid ranges specified in Section 6.9, Table 14, Page 41
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* of the D-PHY specification (v1.2).
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*/
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int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
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unsigned int bpp,
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unsigned int lanes,
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struct phy_configure_opts_mipi_dphy *cfg)
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{
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unsigned long long hs_clk_rate;
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unsigned long long ui;
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if (!cfg)
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return -EINVAL;
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hs_clk_rate = pixel_clock * bpp;
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do_div(hs_clk_rate, lanes);
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ui = ALIGN(PSEC_PER_SEC, hs_clk_rate);
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do_div(ui, hs_clk_rate);
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cfg->clk_miss = 0;
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cfg->clk_post = 60000 + 52 * ui;
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cfg->clk_pre = 8;
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cfg->clk_prepare = 38000;
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cfg->clk_settle = 95000;
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cfg->clk_term_en = 0;
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cfg->clk_trail = 60000;
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cfg->clk_zero = 262000;
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cfg->d_term_en = 0;
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cfg->eot = 0;
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cfg->hs_exit = 100000;
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cfg->hs_prepare = 40000 + 4 * ui;
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cfg->hs_zero = 105000 + 6 * ui;
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cfg->hs_settle = 85000 + 6 * ui;
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cfg->hs_skip = 40000;
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/*
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* The MIPI D-PHY specification (Section 6.9, v1.2, Table 14, Page 40)
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* contains this formula as:
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*
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* T_HS-TRAIL = max(n * 8 * ui, 60 + n * 4 * ui)
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*
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* where n = 1 for forward-direction HS mode and n = 4 for reverse-
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* direction HS mode. There's only one setting and this function does
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* not parameterize on anything other that ui, so this code will
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* assumes that reverse-direction HS mode is supported and uses n = 4.
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*/
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cfg->hs_trail = max(4 * 8 * ui, 60000 + 4 * 4 * ui);
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cfg->init = 100;
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cfg->lpx = 60000;
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cfg->ta_get = 5 * cfg->lpx;
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cfg->ta_go = 4 * cfg->lpx;
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cfg->ta_sure = 2 * cfg->lpx;
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cfg->wakeup = 1000;
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cfg->hs_clk_rate = hs_clk_rate;
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cfg->lanes = lanes;
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return 0;
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}
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EXPORT_SYMBOL(phy_mipi_dphy_get_default_config);
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/*
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* Validate D-PHY configuration according to MIPI D-PHY specification
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* (v1.2, Section Section 6.9 "Global Operation Timing Parameters").
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*/
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int phy_mipi_dphy_config_validate(struct phy_configure_opts_mipi_dphy *cfg)
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{
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unsigned long long ui;
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if (!cfg)
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return -EINVAL;
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ui = ALIGN(PSEC_PER_SEC, cfg->hs_clk_rate);
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do_div(ui, cfg->hs_clk_rate);
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if (cfg->clk_miss > 60000)
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return -EINVAL;
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if (cfg->clk_post < (60000 + 52 * ui))
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return -EINVAL;
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if (cfg->clk_pre < 8)
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return -EINVAL;
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if (cfg->clk_prepare < 38000 || cfg->clk_prepare > 95000)
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return -EINVAL;
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if (cfg->clk_settle < 95000 || cfg->clk_settle > 300000)
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return -EINVAL;
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if (cfg->clk_term_en > 38000)
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return -EINVAL;
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if (cfg->clk_trail < 60000)
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return -EINVAL;
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if ((cfg->clk_prepare + cfg->clk_zero) < 300000)
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return -EINVAL;
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if (cfg->d_term_en > (35000 + 4 * ui))
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return -EINVAL;
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if (cfg->eot > (105000 + 12 * ui))
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return -EINVAL;
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if (cfg->hs_exit < 100000)
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return -EINVAL;
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if (cfg->hs_prepare < (40000 + 4 * ui) ||
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cfg->hs_prepare > (85000 + 6 * ui))
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return -EINVAL;
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if ((cfg->hs_prepare + cfg->hs_zero) < (145000 + 10 * ui))
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return -EINVAL;
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if ((cfg->hs_settle < (85000 + 6 * ui)) ||
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(cfg->hs_settle > (145000 + 10 * ui)))
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return -EINVAL;
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if (cfg->hs_skip < 40000 || cfg->hs_skip > (55000 + 4 * ui))
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return -EINVAL;
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if (cfg->hs_trail < max(8 * ui, 60000 + 4 * ui))
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return -EINVAL;
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if (cfg->init < 100)
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return -EINVAL;
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if (cfg->lpx < 50000)
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return -EINVAL;
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if (cfg->ta_get != (5 * cfg->lpx))
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return -EINVAL;
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if (cfg->ta_go != (4 * cfg->lpx))
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return -EINVAL;
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if (cfg->ta_sure < cfg->lpx || cfg->ta_sure > (2 * cfg->lpx))
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return -EINVAL;
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if (cfg->wakeup < 1000)
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return -EINVAL;
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return 0;
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}
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EXPORT_SYMBOL(phy_mipi_dphy_config_validate);
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