diff options
Diffstat (limited to 'drivers/phy/phy-core-mipi-dphy.c')
| -rw-r--r-- | drivers/phy/phy-core-mipi-dphy.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/drivers/phy/phy-core-mipi-dphy.c b/drivers/phy/phy-core-mipi-dphy.c new file mode 100644 index 000000000..0aa740b73 --- /dev/null +++ b/drivers/phy/phy-core-mipi-dphy.c @@ -0,0 +1,166 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2013 NVIDIA Corporation + * Copyright (C) 2018 Cadence Design Systems Inc. + */ + +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/time64.h> + +#include <linux/phy/phy.h> +#include <linux/phy/phy-mipi-dphy.h> + +#define PSEC_PER_SEC 1000000000000LL + +/* + * Minimum D-PHY timings based on MIPI D-PHY specification. Derived + * from the valid ranges specified in Section 6.9, Table 14, Page 41 + * of the D-PHY specification (v2.1). + */ +int phy_mipi_dphy_get_default_config(unsigned long pixel_clock, + unsigned int bpp, + unsigned int lanes, + struct phy_configure_opts_mipi_dphy *cfg) +{ + unsigned long long hs_clk_rate; + unsigned long long ui; + + if (!cfg) + return -EINVAL; + + hs_clk_rate = pixel_clock * bpp; + do_div(hs_clk_rate, lanes); + + ui = ALIGN(PSEC_PER_SEC, hs_clk_rate); + do_div(ui, hs_clk_rate); + + cfg->clk_miss = 0; + cfg->clk_post = 60000 + 52 * ui; + cfg->clk_pre = 8000; + cfg->clk_prepare = 38000; + cfg->clk_settle = 95000; + cfg->clk_term_en = 0; + cfg->clk_trail = 60000; + cfg->clk_zero = 262000; + cfg->d_term_en = 0; + cfg->eot = 0; + cfg->hs_exit = 100000; + cfg->hs_prepare = 40000 + 4 * ui; + cfg->hs_zero = 105000 + 6 * ui; + cfg->hs_settle = 85000 + 6 * ui; + cfg->hs_skip = 40000; + + /* + * The MIPI D-PHY specification (Section 6.9, v1.2, Table 14, Page 40) + * contains this formula as: + * + * T_HS-TRAIL = max(n * 8 * ui, 60 + n * 4 * ui) + * + * where n = 1 for forward-direction HS mode and n = 4 for reverse- + * direction HS mode. There's only one setting and this function does + * not parameterize on anything other that ui, so this code will + * assumes that reverse-direction HS mode is supported and uses n = 4. + */ + cfg->hs_trail = max(4 * 8 * ui, 60000 + 4 * 4 * ui); + + cfg->init = 100; + cfg->lpx = 50000; + cfg->ta_get = 5 * cfg->lpx; + cfg->ta_go = 4 * cfg->lpx; + cfg->ta_sure = cfg->lpx; + cfg->wakeup = 1000; + + cfg->hs_clk_rate = hs_clk_rate; + cfg->lanes = lanes; + + return 0; +} +EXPORT_SYMBOL(phy_mipi_dphy_get_default_config); + +/* + * Validate D-PHY configuration according to MIPI D-PHY specification + * (v1.2, Section Section 6.9 "Global Operation Timing Parameters"). + */ +int phy_mipi_dphy_config_validate(struct phy_configure_opts_mipi_dphy *cfg) +{ + unsigned long long ui; + + if (!cfg) + return -EINVAL; + + ui = ALIGN(PSEC_PER_SEC, cfg->hs_clk_rate); + do_div(ui, cfg->hs_clk_rate); + + if (cfg->clk_miss > 60000) + return -EINVAL; + + if (cfg->clk_post < (60000 + 52 * ui)) + return -EINVAL; + + if (cfg->clk_pre < 8000) + return -EINVAL; + + if (cfg->clk_prepare < 38000 || cfg->clk_prepare > 95000) + return -EINVAL; + + if (cfg->clk_settle < 95000 || cfg->clk_settle > 300000) + return -EINVAL; + + if (cfg->clk_term_en > 38000) + return -EINVAL; + + if (cfg->clk_trail < 60000) + return -EINVAL; + + if ((cfg->clk_prepare + cfg->clk_zero) < 300000) + return -EINVAL; + + if (cfg->d_term_en > (35000 + 4 * ui)) + return -EINVAL; + + if (cfg->eot > (105000 + 12 * ui)) + return -EINVAL; + + if (cfg->hs_exit < 100000) + return -EINVAL; + + if (cfg->hs_prepare < (40000 + 4 * ui) || + cfg->hs_prepare > (85000 + 6 * ui)) + return -EINVAL; + + if ((cfg->hs_prepare + cfg->hs_zero) < (145000 + 10 * ui)) + return -EINVAL; + + if ((cfg->hs_settle < (85000 + 6 * ui)) || + (cfg->hs_settle > (145000 + 10 * ui))) + return -EINVAL; + + if (cfg->hs_skip < 40000 || cfg->hs_skip > (55000 + 4 * ui)) + return -EINVAL; + + if (cfg->hs_trail < max(8 * ui, 60000 + 4 * ui)) + return -EINVAL; + + if (cfg->init < 100) + return -EINVAL; + + if (cfg->lpx < 50000) + return -EINVAL; + + if (cfg->ta_get != (5 * cfg->lpx)) + return -EINVAL; + + if (cfg->ta_go != (4 * cfg->lpx)) + return -EINVAL; + + if (cfg->ta_sure < cfg->lpx || cfg->ta_sure > (2 * cfg->lpx)) + return -EINVAL; + + if (cfg->wakeup < 1000) + return -EINVAL; + + return 0; +} +EXPORT_SYMBOL(phy_mipi_dphy_config_validate); |