RE: [PATCH v2 9/9] phy: cadence-torrent: Add support to drive refclk out

Swapnil Kashinath Jakhade
2021-03-09T14:23:10Z

Hi Kishon,

> -----Original Message-----
> From: Kishon Vijay Abraham I <kishon@ti.com>
> Sent: Monday, February 22, 2021 4:53 PM
> To: Kishon Vijay Abraham I <kishon@ti.com>; Vinod Koul
> <vkoul@kernel.org>; Rob Herring <robh+dt@kernel.org>; Peter Rosin
> <peda@axentia.se>; Swapnil Kashinath Jakhade <sjakhade@cadence.com>
> Cc: linux-kernel@vger.kernel.org; devicetree@vger.kernel.org; linux-
> phy@lists.infradead.org
> Subject: [PATCH v2 9/9] phy: cadence-torrent: Add support to drive refclk out
>
> EXTERNAL MAIL
>
>
> cmn_refclk_<p/m> lines in Torrent SERDES is used for connecting 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.
>
> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
> ---
> drivers/phy/cadence/phy-cadence-torrent.c | 202 +++++++++++++++++++++-
> 1 file changed, 199 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/phy/cadence/phy-cadence-torrent.c
> b/drivers/phy/cadence/phy-cadence-torrent.c
> index f310e15d94cb..07eebdd90d4b 100644
> --- a/drivers/phy/cadence/phy-cadence-torrent.c
> +++ b/drivers/phy/cadence/phy-cadence-torrent.c
> @@ -7,7 +7,9 @@
> */
>
> #include <dt-bindings/phy/phy.h>
> +#include <dt-bindings/phy/phy-cadence-torrent.h>
> #include <linux/clk.h>
> +#include <linux/clk-provider.h>
> #include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/io.h>
> @@ -76,6 +78,8 @@
> * register offsets from SD0801 PHY register block base (i.e MHDP
> * register base + 0x500000)
> */
> +#define CMN_CDIAG_REFCLK_OVRD 0x004CU
> +#define CMN_CDIAG_REFCLK_DRV0_CTRL 0x0050U

Nitpick, this can be added sequentially.

> #define CMN_SSM_BANDGAP_TMR 0x0021U
> #define CMN_SSM_BIAS_TMR 0x0022U
> #define CMN_PLLSM0_PLLPRE_TMR 0x002AU
> @@ -206,6 +210,8 @@
> #define RX_DIAG_ACYA 0x01FFU
>
> /* PHY PCS common registers */
> +#define PHY_PIPE_CMN_CTRL1 0x0000U
> +#define PHY_ISO_CMN_CTRL 0x0008U
> #define PHY_PLL_CFG 0x000EU
> #define PHY_PIPE_USB3_GEN2_PRE_CFG0 0x0020U
> #define PHY_PIPE_USB3_GEN2_POST_CFG0 0x0022U
> @@ -216,6 +222,10 @@
> #define PHY_PMA_CMN_CTRL2 0x0001U
> #define PHY_PMA_PLL_RAW_CTRL 0x0003U
>
> +static const char * const clk_names[] = {
> + [CDNS_TORRENT_REFCLK_DRIVER] = "refclk-driver",
> +};
> +
> static const struct reg_field phy_pll_cfg =
> REG_FIELD(PHY_PLL_CFG, 0, 1);
>
> @@ -231,6 +241,36 @@ static const struct reg_field phy_pma_pll_raw_ctrl =
> static const struct reg_field phy_reset_ctrl =
> REG_FIELD(PHY_RESET, 8, 8);
>
> +#define REFCLK_OUT_NUM_CONFIGURATIONS_PCS_CONFIG 2

This could be reduced just to REFCLK_OUT_NUM_PCS_CONFIG, but up to you.
Same below.

> +
> +enum cdns_torrent_refclk_out_pcs {
> + PHY_ISO_CMN_CTRL_8,
> + PHY_PIPE_CMN_CTRL1_0,
> +};
> +
> +#define REFCLK_OUT_NUM_CONFIGURATIONS_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_pcs_cfg[] = {
> + [PHY_ISO_CMN_CTRL_8] = REG_FIELD(PHY_ISO_CMN_CTRL, 8,
> 8),
> + [PHY_PIPE_CMN_CTRL1_0] = REG_FIELD(PHY_PIPE_CMN_CTRL1,
> 0, 0),
> +};
> +
> +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,
> @@ -279,6 +319,8 @@ struct cdns_torrent_phy {
> struct regmap_field *phy_pma_cmn_ctrl_2;
> struct regmap_field *phy_pma_pll_raw_ctrl;
> struct regmap_field *phy_reset_ctrl;
> + struct clk *clks[CDNS_TORRENT_REFCLK_DRIVER + 1];
> + struct clk_onecell_data clk_data;
> };
>
> enum phy_powerstate {
> @@ -288,6 +330,16 @@ enum phy_powerstate {
> POWERSTATE_A3 = 3,
> };
>
> +struct cdns_torrent_derived_refclk {
> + struct clk_hw hw;
> + struct regmap_field
> *pcs_fields[REFCLK_OUT_NUM_CONFIGURATIONS_PCS_CONFIG];
> + struct regmap_field
> *cmn_fields[REFCLK_OUT_NUM_CONFIGURATIONS_CMN_CONFIG];
> + struct clk_init_data clk_data;
> +};
> +
> +#define to_cdns_torrent_derived_refclk(_hw) \
> + container_of(_hw, struct
> cdns_torrent_derived_refclk, hw)
> +
> static int cdns_torrent_phy_init(struct phy *phy);
> static int cdns_torrent_dp_init(struct phy *phy);
> static int cdns_torrent_dp_run(struct cdns_torrent_phy *cdns_phy,
> @@ -1604,6 +1656,111 @@ static int cdns_torrent_dp_run(struct
> cdns_torrent_phy *cdns_phy, u32 num_lanes)
> return ret;
> }
>
> +static int cdns_torrent_derived_refclk_enable(struct clk_hw *hw)
> +{
> + struct cdns_torrent_derived_refclk *derived_refclk =
> to_cdns_torrent_derived_refclk(hw);
> +
> + regmap_field_write(derived_refclk-
> >cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_6], 0);
> + regmap_field_write(derived_refclk-
> >cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_4], 1);
> + regmap_field_write(derived_refclk-
> >cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_5], 1);
> + regmap_field_write(derived_refclk-
> >cmn_fields[CMN_CDIAG_REFCLK_DRV0_CTRL_1], 0);
> + regmap_field_write(derived_refclk-
> >cmn_fields[CMN_CDIAG_REFCLK_OVRD_4], 1);
> + regmap_field_write(derived_refclk-
> >pcs_fields[PHY_PIPE_CMN_CTRL1_0], 1);
> + regmap_field_write(derived_refclk-
> >pcs_fields[PHY_ISO_CMN_CTRL_8], 1);
> +
> + return 0;
> +}
> +
> +static void cdns_torrent_derived_refclk_disable(struct clk_hw *hw)
> +{
> + struct cdns_torrent_derived_refclk *derived_refclk =
> to_cdns_torrent_derived_refclk(hw);
> +
> + regmap_field_write(derived_refclk-
> >pcs_fields[PHY_ISO_CMN_CTRL_8], 0);
> +}
> +

PHY_ISO_CMN_CTRL is a PHY isolation register. Not sure, but is this correct
to control phy_en_refclk to enable/disable refclk output from here?

> +static int cdns_torrent_derived_refclk_is_enabled(struct clk_hw *hw)
> +{
> + struct cdns_torrent_derived_refclk *derived_refclk =
> to_cdns_torrent_derived_refclk(hw);
> + int val;
> +
> + regmap_field_read(derived_refclk-
> >pcs_fields[PHY_ISO_CMN_CTRL_8], &val);
> +
> + return !!val;
> +}
> +
> +static const struct clk_ops cdns_torrent_derived_refclk_ops = {
> + .enable = cdns_torrent_derived_refclk_enable,
> + .disable = cdns_torrent_derived_refclk_disable,
> + .is_enabled = cdns_torrent_derived_refclk_is_enabled,
> +};
> +
> +static int cdns_torrent_derived_refclk_register(struct cdns_torrent_phy
> *cdns_phy)
> +{
> + struct cdns_torrent_derived_refclk *derived_refclk;
> + struct device *dev = cdns_phy->dev;
> + struct regmap_field *field;
> + struct clk_init_data *init;
> + const char *parent_name;
> + struct regmap *regmap;
> + char clk_name[100];
> + struct clk *clk;
> + int i;
> +
> + 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_TORRENT_REFCLK_DRIVER]);
> +
> + 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);
> + }
> +
> + init = &derived_refclk->clk_data;
> +
> + if (clk) {
> + parent_name = __clk_get_name(clk);
> + init->parent_names = &parent_name;
> + init->num_parents = 1;
> + }
> + init->ops = &cdns_torrent_derived_refclk_ops;
> + init->flags = 0;
> + init->name = clk_name;
> +
> + regmap = cdns_phy->regmap_phy_pcs_common_cdb;
> + for (i = 0; i < REFCLK_OUT_NUM_CONFIGURATIONS_PCS_CONFIG;
> i++) {
> + field = devm_regmap_field_alloc(dev, regmap,
> refclk_out_pcs_cfg[i]);
> + if (IS_ERR(field)) {
> + dev_err(dev, "PCS reg field init failed\n");
> + return PTR_ERR(field);
> + }
> + derived_refclk->pcs_fields[i] = field;
> + }
> +
> + regmap = cdns_phy->regmap_common_cdb;
> + for (i = 0; i < REFCLK_OUT_NUM_CONFIGURATIONS_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);
> + }
> + derived_refclk->cmn_fields[i] = field;
> + }
> +
> + derived_refclk->hw.init = init;
> +
> + clk = devm_clk_register(dev, &derived_refclk->hw);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + cdns_phy->clks[CDNS_TORRENT_REFCLK_DRIVER] = clk;
> +
> + return 0;
> +}
> +
> static int cdns_torrent_phy_on(struct phy *phy)
> {
> struct cdns_torrent_inst *inst = phy_get_drvdata(phy);
> @@ -2071,6 +2228,37 @@ int cdns_torrent_phy_configure_multilink(struct
> cdns_torrent_phy *cdns_phy)
> return 0;
> }
>
> +static void cdns_torrent_clk_cleanup(struct cdns_torrent_phy *cdns_phy)
> +{
> + struct device *dev = cdns_phy->dev;
> +
> + of_clk_del_provider(dev->of_node);
> +}
> +
> +static int cdns_torrent_clk_register(struct cdns_torrent_phy *cdns_phy)
> +{
> + struct device *dev = cdns_phy->dev;
> + struct device_node *node = dev->of_node;
> + int ret;
> +
> + ret = cdns_torrent_derived_refclk_register(cdns_phy);
> + if (ret) {
> + dev_err(dev, "failed to register derived refclk\n");
> + return ret;
> + }
> +
> + cdns_phy->clk_data.clks = cdns_phy->clks;
> + cdns_phy->clk_data.clk_num = CDNS_TORRENT_REFCLK_DRIVER + 1;
> +
> + ret = of_clk_add_provider(node, of_clk_src_onecell_get, &cdns_phy-
> >clk_data);
> + if (ret) {
> + dev_err(dev, "Failed to add clock provider: %s\n", node-
> >name);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static int cdns_torrent_phy_probe(struct platform_device *pdev)
> {
> struct cdns_torrent_phy *cdns_phy;
> @@ -2134,17 +2322,21 @@ static int cdns_torrent_phy_probe(struct
> platform_device *pdev)
> if (ret)
> return ret;
>
> + ret = cdns_torrent_clk_register(cdns_phy);
> + if (ret)
> + return ret;
> +
> ret = clk_prepare_enable(cdns_phy->clk);
> if (ret) {
> dev_err(cdns_phy->dev, "Failed to prepare ref clock\n");
> - return ret;
> + goto clk_cleanup;
> }
>
> cdns_phy->ref_clk_rate = clk_get_rate(cdns_phy->clk);
> if (!(cdns_phy->ref_clk_rate)) {
> dev_err(cdns_phy->dev, "Failed to get ref clock rate\n");
> - clk_disable_unprepare(cdns_phy->clk);
> - return -EINVAL;
> + ret = -EINVAL;
> + goto clk_disable;
> }
>
> /* Enable APB */
> @@ -2322,7 +2514,10 @@ static int cdns_torrent_phy_probe(struct
> platform_device *pdev)
> reset_control_put(cdns_phy->phys[i].lnk_rst);
> of_node_put(child);
> reset_control_assert(cdns_phy->apb_rst);
> +clk_disable:
> clk_disable_unprepare(cdns_phy->clk);
> +clk_cleanup:
> + cdns_torrent_clk_cleanup(cdns_phy);
> return ret;
> }
>
> @@ -2339,6 +2534,7 @@ static int cdns_torrent_phy_remove(struct
> platform_device *pdev)
> }
>
> clk_disable_unprepare(cdns_phy->clk);
> + cdns_torrent_clk_cleanup(cdns_phy);
>
> return 0;
> }
> --
> 2.17.1

Thanks & regards,
Swapnil