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path: root/drivers/phy/phy-core-mipi-dphy.c
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Diffstat (limited to 'drivers/phy/phy-core-mipi-dphy.c')
-rw-r--r--drivers/phy/phy-core-mipi-dphy.c166
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);