diff options
Diffstat (limited to 'drivers/gpu/drm/tegra/mipi-phy.c')
-rw-r--r-- | drivers/gpu/drm/tegra/mipi-phy.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/drivers/gpu/drm/tegra/mipi-phy.c b/drivers/gpu/drm/tegra/mipi-phy.c new file mode 100644 index 00000000000..e2c4aedaee7 --- /dev/null +++ b/drivers/gpu/drm/tegra/mipi-phy.c @@ -0,0 +1,138 @@ +/* + * Copyright (C) 2013 NVIDIA Corporation + * + * Permission to use, copy, modify, distribute, and sell this software and its + * documentation for any purpose is hereby granted without fee, provided that + * the above copyright notice appear in all copies and that both that copyright + * notice and this permission notice appear in supporting documentation, and + * that the name of the copyright holders not be used in advertising or + * publicity pertaining to distribution of the software without specific, + * written prior permission. The copyright holders make no representations + * about the suitability of this software for any purpose. It is provided "as + * is" without express or implied warranty. + * + * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO + * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, + * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE + * OF THIS SOFTWARE. + */ + +#include <linux/errno.h> +#include <linux/kernel.h> + +#include "mipi-phy.h" + +/* + * Default D-PHY timings based on MIPI D-PHY specification. Derived from + * the valid ranges specified in Section 5.9 of the D-PHY specification + * with minor adjustments. + */ +int mipi_dphy_timing_get_default(struct mipi_dphy_timing *timing, + unsigned long period) +{ + timing->clkmiss = 0; + timing->clkpost = 70 + 52 * period; + timing->clkpre = 8; + timing->clkprepare = 65; + timing->clksettle = 95; + timing->clktermen = 0; + timing->clktrail = 80; + timing->clkzero = 260; + timing->dtermen = 0; + timing->eot = 0; + timing->hsexit = 120; + timing->hsprepare = 65 + 5 * period; + timing->hszero = 145 + 5 * period; + timing->hssettle = 85 + 6 * period; + timing->hsskip = 40; + timing->hstrail = max(8 * period, 60 + 4 * period); + timing->init = 100000; + timing->lpx = 60; + timing->taget = 5 * timing->lpx; + timing->tago = 4 * timing->lpx; + timing->tasure = 2 * timing->lpx; + timing->wakeup = 1000000; + + return 0; +} + +/* + * Validate D-PHY timing according to MIPI Alliance Specification for D-PHY, + * Section 5.9 "Global Operation Timing Parameters". + */ +int mipi_dphy_timing_validate(struct mipi_dphy_timing *timing, + unsigned long period) +{ + if (timing->clkmiss > 60) + return -EINVAL; + + if (timing->clkpost < (60 + 52 * period)) + return -EINVAL; + + if (timing->clkpre < 8) + return -EINVAL; + + if (timing->clkprepare < 38 || timing->clkprepare > 95) + return -EINVAL; + + if (timing->clksettle < 95 || timing->clksettle > 300) + return -EINVAL; + + if (timing->clktermen > 38) + return -EINVAL; + + if (timing->clktrail < 60) + return -EINVAL; + + if (timing->clkprepare + timing->clkzero < 300) + return -EINVAL; + + if (timing->dtermen > 35 + 4 * period) + return -EINVAL; + + if (timing->eot > 105 + 12 * period) + return -EINVAL; + + if (timing->hsexit < 100) + return -EINVAL; + + if (timing->hsprepare < 40 + 4 * period || + timing->hsprepare > 85 + 6 * period) + return -EINVAL; + + if (timing->hsprepare + timing->hszero < 145 + 10 * period) + return -EINVAL; + + if ((timing->hssettle < 85 + 6 * period) || + (timing->hssettle > 145 + 10 * period)) + return -EINVAL; + + if (timing->hsskip < 40 || timing->hsskip > 55 + 4 * period) + return -EINVAL; + + if (timing->hstrail < max(8 * period, 60 + 4 * period)) + return -EINVAL; + + if (timing->init < 100000) + return -EINVAL; + + if (timing->lpx < 50) + return -EINVAL; + + if (timing->taget != 5 * timing->lpx) + return -EINVAL; + + if (timing->tago != 4 * timing->lpx) + return -EINVAL; + + if (timing->tasure < timing->lpx || timing->tasure > 2 * timing->lpx) + return -EINVAL; + + if (timing->wakeup < 1000000) + return -EINVAL; + + return 0; +} |