phy: cadence: Sierra: Add support for derived reference clock output

Sierra has derived differential reference clock output which is sourced
after the spread spectrum generation has been added. Add support to drive
derived reference clock out of serdes. Model this derived clock as a
"clock" so that platforms using this can enable it.

Sierra Main LC VCO PLL divider 1 clock is programmed to output 100MHz
clock output.

Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
Reviewed-by: Aswath Govindraju <a-govindraju@ti.com>
Link: https://lore.kernel.org/r/20211223060137.9252-16-sjakhade@cadence.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/cadence/phy-cadence-sierra.c

@@ -34,6 +34,7 @@
 #define SIERRA_CMN_PLLLC_LF_COEFF_MODE1_PREG		0x49
 #define SIERRA_CMN_PLLLC_LF_COEFF_MODE0_PREG		0x4A
 #define SIERRA_CMN_PLLLC_LOCK_CNTSTART_PREG		0x4B
+#define SIERRA_CMN_PLLLC_CLK1_PREG			0x4D
 #define SIERRA_CMN_PLLLC_BWCAL_MODE1_PREG		0x4F
 #define SIERRA_CMN_PLLLC_BWCAL_MODE0_PREG		0x50
 #define SIERRA_CMN_PLLLC_DSMCORR_PREG			0x51
@@ -203,7 +204,7 @@
 #define SIERRA_MAX_LANES				16
 #define PLL_LOCK_TIME					100000
 
-#define CDNS_SIERRA_OUTPUT_CLOCKS			2
+#define CDNS_SIERRA_OUTPUT_CLOCKS			3
 #define CDNS_SIERRA_INPUT_CLOCKS			5
 enum cdns_sierra_clock_input {
 	PHY_CLK,
@@ -226,10 +227,15 @@ static const struct reg_field pllctrl_lock =
 				REG_FIELD(SIERRA_PLLCTRL_STATUS_PREG, 0, 0);
 static const struct reg_field phy_iso_link_ctrl_1 =
 				REG_FIELD(SIERRA_PHY_ISO_LINK_CTRL, 1, 1);
+static const struct reg_field cmn_plllc_clk1outdiv_preg =
+				REG_FIELD(SIERRA_CMN_PLLLC_CLK1_PREG, 0, 6);
+static const struct reg_field cmn_plllc_clk1_en_preg =
+				REG_FIELD(SIERRA_CMN_PLLLC_CLK1_PREG, 12, 12);
 
 static const char * const clk_names[] = {
 	[CDNS_SIERRA_PLL_CMNLC] = "pll_cmnlc",
 	[CDNS_SIERRA_PLL_CMNLC1] = "pll_cmnlc1",
+	[CDNS_SIERRA_DERIVED_REFCLK] = "refclk_der",
 };
 
 enum cdns_sierra_cmn_plllc {
@@ -277,6 +283,16 @@ static u32 cdns_sierra_pll_mux_table[][SIERRA_NUM_CMN_PLLC_PARENTS] = {
 	[CMN_PLLLC1] = { 1, 0 },
 };
 
+struct cdns_sierra_derived_refclk {
+	struct clk_hw           hw;
+	struct regmap_field     *cmn_plllc_clk1outdiv_preg;
+	struct regmap_field     *cmn_plllc_clk1_en_preg;
+	struct clk_init_data	clk_data;
+};
+
+#define to_cdns_sierra_derived_refclk(_hw)	\
+			container_of(_hw, struct cdns_sierra_derived_refclk, hw)
+
 enum cdns_sierra_phy_type {
 	TYPE_NONE,
 	TYPE_PCIE,
@@ -766,6 +782,91 @@ static int cdns_sierra_phy_register_pll_mux(struct cdns_sierra_phy *sp)
 	return 0;
 }
 
+static int cdns_sierra_derived_refclk_enable(struct clk_hw *hw)
+{
+	struct cdns_sierra_derived_refclk *derived_refclk = to_cdns_sierra_derived_refclk(hw);
+
+	regmap_field_write(derived_refclk->cmn_plllc_clk1_en_preg, 0x1);
+
+	/* Programming to get 100Mhz clock output in ref_der_clk_out 5GHz VCO/50 = 100MHz */
+	regmap_field_write(derived_refclk->cmn_plllc_clk1outdiv_preg, 0x2E);
+
+	return 0;
+}
+
+static void cdns_sierra_derived_refclk_disable(struct clk_hw *hw)
+{
+	struct cdns_sierra_derived_refclk *derived_refclk = to_cdns_sierra_derived_refclk(hw);
+
+	regmap_field_write(derived_refclk->cmn_plllc_clk1_en_preg, 0);
+}
+
+static int cdns_sierra_derived_refclk_is_enabled(struct clk_hw *hw)
+{
+	struct cdns_sierra_derived_refclk *derived_refclk = to_cdns_sierra_derived_refclk(hw);
+	int val;
+
+	regmap_field_read(derived_refclk->cmn_plllc_clk1_en_preg, &val);
+
+	return !!val;
+}
+
+static const struct clk_ops cdns_sierra_derived_refclk_ops = {
+	.enable = cdns_sierra_derived_refclk_enable,
+	.disable = cdns_sierra_derived_refclk_disable,
+	.is_enabled = cdns_sierra_derived_refclk_is_enabled,
+};
+
+static int cdns_sierra_derived_refclk_register(struct cdns_sierra_phy *sp)
+{
+	struct cdns_sierra_derived_refclk *derived_refclk;
+	struct device *dev = sp->dev;
+	struct regmap_field *field;
+	struct clk_init_data *init;
+	struct regmap *regmap;
+	char clk_name[100];
+	struct clk *clk;
+
+	derived_refclk = devm_kzalloc(dev, sizeof(*derived_refclk), GFP_KERNEL);
+	if (!derived_refclk)
+		return -ENOMEM;
+
+	snprintf(clk_name, sizeof(clk_name), "%s_%s", dev_name(dev),
+		 clk_names[CDNS_SIERRA_DERIVED_REFCLK]);
+
+	init = &derived_refclk->clk_data;
+
+	init->ops = &cdns_sierra_derived_refclk_ops;
+	init->flags = 0;
+	init->name = clk_name;
+
+	regmap = sp->regmap_common_cdb;
+
+	field = devm_regmap_field_alloc(dev, regmap, cmn_plllc_clk1outdiv_preg);
+	if (IS_ERR(field)) {
+		dev_err(dev, "cmn_plllc_clk1outdiv_preg reg field init failed\n");
+		return PTR_ERR(field);
+	}
+	derived_refclk->cmn_plllc_clk1outdiv_preg = field;
+
+	field = devm_regmap_field_alloc(dev, regmap, cmn_plllc_clk1_en_preg);
+	if (IS_ERR(field)) {
+		dev_err(dev, "cmn_plllc_clk1_en_preg reg field init failed\n");
+		return PTR_ERR(field);
+	}
+	derived_refclk->cmn_plllc_clk1_en_preg = field;
+
+	derived_refclk->hw.init = init;
+
+	clk = devm_clk_register(dev, &derived_refclk->hw);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	sp->output_clks[CDNS_SIERRA_DERIVED_REFCLK] = clk;
+
+	return 0;
+}
+
 static void cdns_sierra_clk_unregister(struct cdns_sierra_phy *sp)
 {
 	struct device *dev = sp->dev;
@@ -786,6 +887,12 @@ static int cdns_sierra_clk_register(struct cdns_sierra_phy *sp)
 		return ret;
 	}
 
+	ret = cdns_sierra_derived_refclk_register(sp);
+	if (ret) {
+		dev_err(dev, "Failed to register derived refclk\n");
+		return ret;
+	}
+
 	sp->clk_data.clks = sp->output_clks;
 	sp->clk_data.clk_num = CDNS_SIERRA_OUTPUT_CLOCKS;
 	ret = of_clk_add_provider(node, of_clk_src_onecell_get, &sp->clk_data);