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path: root/drivers/gpu/drm/tegra/mipi-phy.c
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Diffstat (limited to 'drivers/gpu/drm/tegra/mipi-phy.c')
-rw-r--r--drivers/gpu/drm/tegra/mipi-phy.c138
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 000000000000..e2c4aedaee78
--- /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;
+}