phy: cdns-dphy: Add Rx support

The Cadence DPHY can be used to receive image data over the CSI-2
protocol. Add support for Rx mode. The programming sequence differs from
the Tx mode so it is added as a separate set of hooks to isolate the two
paths.

The PHY is in Tx mode by default and it needs to be set in Rx mode by
setting the submode to PHY_MIPI_DPHY_SUBMODE_RX in the set_mode()
callback.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>

diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
index af375d47011484e50d3d4a3d21993f869958878c..1f40f3817e7a41d7e52c04982db1a255fc1ec3b1 100644 (file)
--- a/drivers/phy/cadence/cdns-dphy.c
+++ b/drivers/phy/cadence/cdns-dphy.c
@@ -1,11 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright: 2017-2018 Cadence Design Systems, Inc.
+ * Copyright (C) 2021 Texas Instruments Incorporated - https://www.ti.com/
  */
 
 #include <linux/bitops.h>
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
@@ -25,10 +28,14 @@
 #define DPHY_PMA_RCLK(reg)             (0x600 + (reg))
 #define DPHY_PMA_RDATA(lane, reg)      (0x700 + ((lane) * 0x100) + (reg))
 #define DPHY_PCS(reg)                  (0xb00 + (reg))
+#define DPHY_ISO(reg)                  (0xc00 + (reg))
 
 #define DPHY_CMN_SSM                   DPHY_PMA_CMN(0x20)
 #define DPHY_CMN_SSM_EN                        BIT(0)
+#define DPHY_CMN_RX_BANDGAP_TIMER_MASK GENMASK(8, 1)
 #define DPHY_CMN_TX_MODE_EN            BIT(9)
+#define DPHY_CMN_RX_MODE_EN            BIT(10)
+#define DPHY_CMN_RX_BANDGAP_TIMER      0x14
 
 #define DPHY_CMN_PWM                   DPHY_PMA_CMN(0x40)
 #define DPHY_CMN_PWM_DIV(x)            ((x) << 20)
@@ -45,10 +52,27 @@
 #define DPHY_CMN_OPDIV_FROM_REG                BIT(6)
 #define DPHY_CMN_OPDIV(x)              ((x) << 7)
 
+#define DPHY_BAND_CFG                  DPHY_PCS(0x0)
+#define DPHY_BAND_CFG_LEFT_BAND                GENMASK(4, 0)
+#define DPHY_BAND_CFG_RIGHT_BAND       GENMASK(9, 5)
+
 #define DPHY_PSM_CFG                   DPHY_PCS(0x4)
 #define DPHY_PSM_CFG_FROM_REG          BIT(0)
 #define DPHY_PSM_CLK_DIV(x)            ((x) << 1)
 
+#define DPHY_POWER_ISLAND_EN_DATA      DPHY_PCS(0x8)
+#define DPHY_POWER_ISLAND_EN_DATA_VAL  0xaaaaaaaa
+#define DPHY_POWER_ISLAND_EN_CLK       DPHY_PCS(0xc)
+#define DPHY_POWER_ISLAND_EN_CLK_VAL   0xaa
+
+#define DPHY_ISO_CL_CTRL_L             DPHY_ISO(0x10)
+#define DPHY_ISO_DL_CTRL_L0            DPHY_ISO(0x14)
+#define DPHY_ISO_DL_CTRL_L1            DPHY_ISO(0x20)
+#define DPHY_ISO_DL_CTRL_L2            DPHY_ISO(0x30)
+#define DPHY_ISO_DL_CTRL_L3            DPHY_ISO(0x3c)
+#define DPHY_ISO_LANE_READY_BIT                0
+#define DPHY_ISO_LANE_READY_TIMEOUT_MS 100UL
+
 #define DSI_HBP_FRAME_OVERHEAD         12
 #define DSI_HSA_FRAME_OVERHEAD         14
 #define DSI_HFP_FRAME_OVERHEAD         6
@@ -57,6 +81,9 @@
 #define DSI_NULL_FRAME_OVERHEAD                6
 #define DSI_EOT_PKT_SIZE               4
 
+#define DPHY_LANES_MIN                 1
+#define DPHY_LANES_MAX                 4
+
 struct cdns_dphy_cfg {
        u8 pll_ipdiv;
        u8 pll_opdiv;
@@ -312,6 +339,214 @@ static const struct cdns_dphy_ops tx_ref_dphy_ops = {
        .set_psm_div = cdns_dphy_ref_set_psm_div,
 };
 
+static int cdns_dphy_rx_power_on(struct cdns_dphy *dphy)
+{
+       /* Start RX state machine. */
+       writel(DPHY_CMN_SSM_EN | DPHY_CMN_RX_MODE_EN |
+              FIELD_PREP(DPHY_CMN_RX_BANDGAP_TIMER_MASK,
+                         DPHY_CMN_RX_BANDGAP_TIMER),
+              dphy->regs + DPHY_CMN_SSM);
+
+       return 0;
+}
+
+static int cdns_dphy_rx_power_off(struct cdns_dphy *dphy)
+{
+       writel(0, dphy->regs + DPHY_CMN_SSM);
+
+       return 0;
+}
+
+static int cdns_dphy_rx_get_band_ctrl(unsigned long hs_clk_rate)
+{
+       unsigned int rate = hs_clk_rate / 1000000UL;
+
+       if (rate < 80 || rate >= 2500)
+               return -EOPNOTSUPP;
+
+       if (rate >= 80 && rate < 100)
+               return 0;
+
+       if (rate >= 100 && rate < 120)
+               return 1;
+
+       if (rate >= 120 && rate < 160)
+               return 2;
+
+       if (rate >= 160 && rate < 200)
+               return 3;
+
+       if (rate >= 200 && rate < 240)
+               return 4;
+
+       if (rate >= 240 && rate < 280)
+               return 5;
+
+       if (rate >= 280 && rate < 320)
+               return 6;
+
+       if (rate >= 320 && rate < 360)
+               return 7;
+
+       if (rate >= 360 && rate < 400)
+               return 8;
+
+       if (rate >= 400 && rate < 480)
+               return 9;
+
+       if (rate >= 480 && rate < 560)
+               return 10;
+
+       if (rate >= 560 && rate < 640)
+               return 11;
+
+       if (rate >= 640 && rate < 720)
+               return 12;
+
+       if (rate >= 720 && rate < 800)
+               return 13;
+
+       if (rate >= 800 && rate < 880)
+               return 14;
+
+       if (rate >= 880 && rate < 1040)
+               return 15;
+
+       if (rate >= 1040 && rate < 1200)
+               return 16;
+
+       if (rate >= 1200 && rate < 1350)
+               return 17;
+
+       if (rate >= 1350 && rate < 1500)
+               return 18;
+
+       if (rate >= 1500 && rate < 1750)
+               return 19;
+
+       if (rate >= 1750 && rate < 2000)
+               return 20;
+
+       if (rate >= 2000 && rate < 2250)
+               return 21;
+
+       if (rate >= 2250 && rate < 2500)
+               return 22;
+
+       /* Unreachable. */
+       WARN(1, "Reached unreachable code.");
+       return -EINVAL;
+}
+
+static int cdns_dphy_rx_wait_for_bit(void __iomem *addr, unsigned int bit)
+{
+       u32 val;
+
+       return readl_relaxed_poll_timeout(addr, val, val & BIT(bit), 10,
+                                         DPHY_ISO_LANE_READY_TIMEOUT_MS * 1000);
+}
+
+static int cdns_dphy_rx_wait_lane_ready(struct cdns_dphy *dphy, int lanes)
+{
+       void __iomem *reg = dphy->regs;
+       int ret;
+
+       if (lanes < DPHY_LANES_MIN || lanes > DPHY_LANES_MAX)
+               return -EINVAL;
+
+       /* Clock lane */
+       ret = cdns_dphy_rx_wait_for_bit(reg + DPHY_ISO_CL_CTRL_L,
+                                       DPHY_ISO_LANE_READY_BIT);
+       if (ret)
+               return ret;
+
+       /* Data lanes. Minimum one lane is mandatory. */
+       ret = cdns_dphy_rx_wait_for_bit(reg + DPHY_ISO_DL_CTRL_L0,
+                                       DPHY_ISO_LANE_READY_BIT);
+       if (ret)
+               return ret;
+
+       if (lanes < 2)
+               return 0;
+
+       ret = cdns_dphy_rx_wait_for_bit(reg + DPHY_ISO_DL_CTRL_L1,
+                                       DPHY_ISO_LANE_READY_BIT);
+       if (ret)
+               return ret;
+
+       if (lanes < 3)
+               return 0;
+
+       ret = cdns_dphy_rx_wait_for_bit(reg + DPHY_ISO_DL_CTRL_L2,
+                                       DPHY_ISO_LANE_READY_BIT);
+       if (ret)
+               return ret;
+
+       if (lanes < 4)
+               return 0;
+
+       ret = cdns_dphy_rx_wait_for_bit(reg + DPHY_ISO_DL_CTRL_L3,
+                                       DPHY_ISO_LANE_READY_BIT);
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
+static int cdns_dphy_rx_configure(struct cdns_dphy *dphy,
+                                 union phy_configure_opts *opts)
+{
+       unsigned int reg;
+       int band_ctrl, ret;
+
+       band_ctrl = cdns_dphy_rx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
+       if (band_ctrl < 0)
+               return band_ctrl;
+
+       reg = FIELD_PREP(DPHY_BAND_CFG_LEFT_BAND, band_ctrl) |
+             FIELD_PREP(DPHY_BAND_CFG_RIGHT_BAND, band_ctrl);
+       writel(reg, dphy->regs + DPHY_BAND_CFG);
+
+       /*
+        * Set the required power island phase 2 time. This is mandated by DPHY
+        * specs.
+        */
+       reg = DPHY_POWER_ISLAND_EN_DATA_VAL;
+       writel(reg, dphy->regs + DPHY_POWER_ISLAND_EN_DATA);
+       reg = DPHY_POWER_ISLAND_EN_CLK_VAL;
+       writel(reg, dphy->regs + DPHY_POWER_ISLAND_EN_CLK);
+
+       ret = cdns_dphy_rx_wait_lane_ready(dphy, opts->mipi_dphy.lanes);
+       if (ret) {
+               dev_err(dphy->dev, "DPHY wait for lane ready timeout\n");
+               return ret;
+       }
+
+       return 0;
+}
+
+static int cdns_dphy_rx_validate(struct cdns_dphy *dphy, enum phy_mode mode,
+                                int submode, union phy_configure_opts *opts)
+{
+       int ret;
+
+       if (submode != PHY_MIPI_DPHY_SUBMODE_RX)
+               return -EINVAL;
+
+       ret = cdns_dphy_rx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
+       if (ret < 0)
+               return ret;
+
+       return phy_mipi_dphy_config_validate(&opts->mipi_dphy);
+}
+
+static const struct cdns_dphy_ops rx_ref_dphy_ops = {
+       .power_on = cdns_dphy_rx_power_on,
+       .power_off = cdns_dphy_rx_power_off,
+       .configure = cdns_dphy_rx_configure,
+       .validate = cdns_dphy_rx_validate,
+};
+
 /*
  * This is the reference implementation of DPHY hooks. Specific integration of
  * this IP may have to re-implement some of them depending on how they decided
@@ -319,6 +554,7 @@ static const struct cdns_dphy_ops tx_ref_dphy_ops = {
  */
 static const struct cdns_dphy_driver_data ref_dphy_ops = {
        .tx = &tx_ref_dphy_ops,
+       .rx = &rx_ref_dphy_ops,
 };
 
 static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode, int submode,
@@ -485,5 +721,6 @@ static struct platform_driver cdns_dphy_platform_driver = {
 module_platform_driver(cdns_dphy_platform_driver);
 
 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@bootlin.com>");
+MODULE_AUTHOR("Pratyush Yadav <p.yadav@ti.com>");
 MODULE_DESCRIPTION("Cadence MIPI D-PHY Driver");
 MODULE_LICENSE("GPL");