phy: cadence-torrent: Add support to drive refclk out

cmn_refclk_<p/m> lines in Torrent SERDES are used for connecting an
external reference clock. cmn_refclk_<p/m> can also be configured to
output the reference clock. Model this derived reference clock as a
"clock" so that platforms like AM642 EVM can enable it.

This is used by PCIe to use the same refclk both in local SERDES
and remote device. Add support here to drive refclk out.

Based on: https://lore.kernel.org/all/20210310120840.16447-7-kishon@ti.com/

Signed-off-by: George McCollister <george.mccollister@konsulko.com>
Tested-by: Bryan Brattlof <bb@ti.com>

diff --git a/drivers/phy/cadence/phy-cadence-torrent.c b/drivers/phy/cadence/phy-cadence-torrent.c
index 28fe026223c179e68cf919220f1f8865734574f7..933533b2b0b7338aa6cb04af7bbaf25a91689abe 100644 (file)
--- a/drivers/phy/cadence/phy-cadence-torrent.c
+++ b/drivers/phy/cadence/phy-cadence-torrent.c
@@ -11,16 +11,19 @@
  */
 
 #include <clk.h>
+#include <clk-uclass.h>
 #include <generic-phy.h>
 #include <reset.h>
 #include <dm/device.h>
 #include <dm/device_compat.h>
 #include <dm/device-internal.h>
+#include <dm/devres.h>
 #include <dm/lists.h>
 #include <dm/read.h>
 #include <dm/uclass.h>
 #include <linux/io.h>
 #include <dt-bindings/phy/phy.h>
+#include <dt-bindings/phy/phy-cadence.h>
 #include <regmap.h>
 #include <linux/delay.h>
 #include <linux/string.h>
@@ -64,6 +67,8 @@
 #define CMN_PLLSM1_PLLLOCK_TMR         0x0034U
 #define CMN_CDIAG_CDB_PWRI_OVRD                0x0041U
 #define CMN_CDIAG_XCVRC_PWRI_OVRD      0x0047U
+#define CMN_CDIAG_REFCLK_OVRD          0x004CU
+#define CMN_CDIAG_REFCLK_DRV0_CTRL     0x0050U
 #define CMN_BGCAL_INIT_TMR             0x0064U
 #define CMN_BGCAL_ITER_TMR             0x0065U
 #define CMN_IBCAL_INIT_TMR             0x0074U
@@ -191,6 +196,7 @@
 #define RX_DIAG_ACYA                   0x01FFU
 
 /* PHY PCS common registers */
+#define PHY_PIPE_CMN_CTRL1             0x0000U
 #define PHY_PLL_CFG                    0x000EU
 #define PHY_PIPE_USB3_GEN2_PRE_CFG0    0x0020U
 #define PHY_PIPE_USB3_GEN2_POST_CFG0   0x0022U
@@ -214,6 +220,26 @@ static const struct reg_field phy_pma_pll_raw_ctrl =
 #define reset_control reset_ctl
 #define reset_control_put reset_free
 
+static const struct reg_field phy_pipe_cmn_ctrl1_0 = REG_FIELD(PHY_PIPE_CMN_CTRL1, 0, 0);
+
+#define REFCLK_OUT_NUM_CMN_CONFIG      5
+
+enum cdns_torrent_refclk_out_cmn {
+       CMN_CDIAG_REFCLK_OVRD_4,
+       CMN_CDIAG_REFCLK_DRV0_CTRL_1,
+       CMN_CDIAG_REFCLK_DRV0_CTRL_4,
+       CMN_CDIAG_REFCLK_DRV0_CTRL_5,
+       CMN_CDIAG_REFCLK_DRV0_CTRL_6,
+};
+
+static const struct reg_field refclk_out_cmn_cfg[] = {
+       [CMN_CDIAG_REFCLK_OVRD_4]       = REG_FIELD(CMN_CDIAG_REFCLK_OVRD, 4, 4),
+       [CMN_CDIAG_REFCLK_DRV0_CTRL_1]  = REG_FIELD(CMN_CDIAG_REFCLK_DRV0_CTRL, 1, 1),
+       [CMN_CDIAG_REFCLK_DRV0_CTRL_4]  = REG_FIELD(CMN_CDIAG_REFCLK_DRV0_CTRL, 4, 4),
+       [CMN_CDIAG_REFCLK_DRV0_CTRL_5]  = REG_FIELD(CMN_CDIAG_REFCLK_DRV0_CTRL, 5, 5),
+       [CMN_CDIAG_REFCLK_DRV0_CTRL_6]  = REG_FIELD(CMN_CDIAG_REFCLK_DRV0_CTRL, 6, 6),
+};
+
 enum cdns_torrent_phy_type {
        TYPE_NONE,
        TYPE_DP,
@@ -257,6 +283,9 @@ struct cdns_torrent_phy {
        struct regmap_field *phy_pma_cmn_ctrl_1;
        struct regmap_field *phy_pma_cmn_ctrl_2;
        struct regmap_field *phy_pma_pll_raw_ctrl;
+       struct clk *clks[CDNS_TORRENT_REFCLK_DRIVER + 1];
+       struct regmap_field *phy_pipe_cmn_ctrl1_0;
+       struct regmap_field *cmn_fields[REFCLK_OUT_NUM_CMN_CONFIG];
 };
 
 struct cdns_reg_pairs {
@@ -592,6 +621,141 @@ static int cdns_torrent_phy_configure_multilink(struct cdns_torrent_phy *cdns_ph
        return 0;
 }
 
+struct cdns_torrent_derived_refclk {
+       unsigned int            id;
+       struct cdns_torrent_phy *cdns_phy;
+};
+
+static int cdns_torrent_derived_refclk_of_xlate(struct clk *clk, struct ofnode_phandle_args *args)
+{
+       struct udevice *dev = clk->dev;
+       struct cdns_torrent_derived_refclk *derived_refclk = dev_get_priv(dev);
+
+       if (derived_refclk->id != CDNS_TORRENT_REFCLK_DRIVER)
+               return -EINVAL;
+
+       derived_refclk->id = args->args[0];
+
+       return 0;
+}
+
+static int cdns_torrent_derived_refclk_enable(struct clk *clk)
+{
+       struct udevice *dev = clk->dev;
+       struct cdns_torrent_derived_refclk *derived_refclk = dev_get_priv(dev);
+       struct cdns_torrent_phy *cdns_phy = derived_refclk->cdns_phy;
+
+       if (derived_refclk->id != CDNS_TORRENT_REFCLK_DRIVER)
+               return -EINVAL;
+
+       regmap_field_write(cdns_phy->cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_6], 0);
+       regmap_field_write(cdns_phy->cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_4], 1);
+       regmap_field_write(cdns_phy->cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_5], 1);
+       regmap_field_write(cdns_phy->cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_1], 0);
+       regmap_field_write(cdns_phy->cmn_fields[CMN_CDIAG_REFCLK_OVRD_4], 1);
+       regmap_field_write(cdns_phy->phy_pipe_cmn_ctrl1_0, 1);
+
+       return 0;
+}
+
+static int cdns_torrent_derived_refclk_disable(struct clk *clk)
+{
+       struct udevice *dev = clk->dev;
+       struct cdns_torrent_derived_refclk *derived_refclk = dev_get_priv(dev);
+       struct cdns_torrent_phy *cdns_phy = derived_refclk->cdns_phy;
+
+       regmap_field_write(cdns_phy->phy_pipe_cmn_ctrl1_0, 0);
+
+       return 0;
+}
+
+static const struct clk_ops cdns_torrent_derived_refclk_ops = {
+       .of_xlate = cdns_torrent_derived_refclk_of_xlate,
+       .enable = cdns_torrent_derived_refclk_enable,
+       .disable = cdns_torrent_derived_refclk_disable,
+};
+
+int cdns_torrent_derived_refclk_probe(struct udevice *dev)
+{
+       struct cdns_torrent_derived_refclk *priv = dev_get_priv(dev);
+
+       priv->cdns_phy = dev_get_priv(dev->parent);
+
+       return 0;
+}
+
+U_BOOT_DRIVER(cdns_torrent_derived_refclk) = {
+       .name           = "cdns_torrent_derived_refclk",
+       .id             = UCLASS_CLK,
+       .priv_auto      = sizeof(struct cdns_torrent_derived_refclk),
+       .ops            = &cdns_torrent_derived_refclk_ops,
+       .probe          = cdns_torrent_derived_refclk_probe,
+};
+
+static int cdns_torrent_derived_refclk_register(struct cdns_torrent_phy *cdns_phy)
+{
+       struct driver *cdns_torrent_derived_refclk_drv;
+       struct udevice *dev = cdns_phy->dev;
+       struct regmap_field *field;
+       struct regmap *regmap;
+       struct clk *clk;
+       int rc;
+       int i;
+
+       clk = devm_clk_get_optional(dev, "phy_en_refclk");
+       if (IS_ERR(clk)) {
+               dev_err(dev, "No parent clock for derived_refclk\n");
+               return PTR_ERR(clk);
+       }
+
+       clk_enable(clk);
+
+       regmap = cdns_phy->regmap_phy_pcs_common_cdb;
+       field = devm_regmap_field_alloc(dev, regmap, phy_pipe_cmn_ctrl1_0);
+       if (IS_ERR(field)) {
+               dev_err(dev, "phy_pipe_cmn_ctrl1_0 reg field init failed\n");
+               return PTR_ERR(field);
+       }
+       cdns_phy->phy_pipe_cmn_ctrl1_0 = field;
+
+       regmap = cdns_phy->regmap_common_cdb;
+       for (i = 0; i < REFCLK_OUT_NUM_CMN_CONFIG; i++) {
+               field = devm_regmap_field_alloc(dev, regmap, refclk_out_cmn_cfg[i]);
+               if (IS_ERR(field)) {
+                       dev_err(dev, "CMN reg field init failed\n");
+                       return PTR_ERR(field);
+               }
+               cdns_phy->cmn_fields[i] = field;
+       }
+
+       cdns_torrent_derived_refclk_drv = lists_driver_lookup_name("cdns_torrent_derived_refclk");
+       if (!cdns_torrent_derived_refclk_drv) {
+               dev_err(dev, "Cannot find driver 'cdns_torrent_derived_refclk'\n");
+               return -ENOENT;
+       }
+
+       rc = device_bind(dev, cdns_torrent_derived_refclk_drv, "cdns-torrent-derived-refclk",
+                        NULL, dev_ofnode(dev), NULL);
+       if (rc)
+               dev_err(dev, "cannot bind driver for clock cdns-torrent-derived-refclk\n");
+
+       return 0;
+}
+
+static int cdns_torrent_clk_register(struct cdns_torrent_phy *cdns_phy)
+{
+       struct udevice *dev = cdns_phy->dev;
+       int ret;
+
+       ret = cdns_torrent_derived_refclk_register(cdns_phy);
+       if (ret) {
+               dev_err(dev, "failed to register derived refclk\n");
+               return ret;
+       }
+
+       return 0;
+}
+
 static int cdns_torrent_phy_probe(struct udevice *dev)
 {
        struct cdns_torrent_phy *cdns_phy = dev_get_priv(dev);
@@ -646,6 +810,10 @@ static int cdns_torrent_phy_probe(struct udevice *dev)
        if (ret)
                return ret;
 
+       ret = cdns_torrent_clk_register(cdns_phy);
+       if (ret)
+               return ret;
+
        /* Going through all the available subnodes or children*/
        ofnode_for_each_subnode(child, dev_ofnode(dev)) {
                /* PHY subnode name must be a 'phy' */