Re: [PATCH v2 8/9] phy: Add Cadence D-PHY support

From: Kishon Vijay Abraham I
Date: Mon Nov 12 2018 - 04:53:29 EST

Next message: David Laight: "RE: [PATCH] slab.h: Avoid using & for logical and of booleans"
Previous message: Chao Fan: "Re: [PATCH v11 3/5] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdlien from kexec"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hi Maxime,

On 06/11/18 8:24 PM, Maxime Ripard wrote:
> Cadence has designed a D-PHY that can be used by the, currently in tree,
> DSI bridge (DRM), CSI Transceiver and CSI Receiver (v4l2) drivers.
>
> Only the DSI driver has an ad-hoc driver for that phy at the moment, while
> the v4l2 drivers are completely missing any phy support. In order to make
> that phy support available to all these drivers, without having to
> duplicate that code three times, let's create a generic phy framework
> driver.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt | 21 +-
> Documentation/devicetree/bindings/phy/cdns,dphy.txt | 20 +-
> drivers/phy/cadence/Kconfig | 13 +-
> drivers/phy/cadence/Makefile | 1 +-
> drivers/phy/cadence/cdns-dphy.c | 459 +++++++-
> 5 files changed, 492 insertions(+), 22 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/phy/cdns,dphy.txt
> create mode 100644 drivers/phy/cadence/cdns-dphy.c
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> index f5725bb6c61c..525a4bfd8634 100644
> --- a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> +++ b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> @@ -31,28 +31,7 @@ Required subnodes:
> - one subnode per DSI device connected on the DSI bus. Each DSI device should
> contain a reg property encoding its virtual channel.
>
> -Cadence DPHY
> -============
> -
> -Cadence DPHY block.
> -
> -Required properties:
> -- compatible: should be set to "cdns,dphy".
> -- reg: physical base address and length of the DPHY registers.
> -- clocks: DPHY reference clocks.
> -- clock-names: must contain "psm" and "pll_ref".
> -- #phy-cells: must be set to 0.
> -
> -
> Example:
> - dphy0: dphy@fd0e0000{
> - compatible = "cdns,dphy";
> - reg = <0x0 0xfd0e0000 0x0 0x1000>;
> - clocks = <&psm_clk>, <&pll_ref_clk>;
> - clock-names = "psm", "pll_ref";
> - #phy-cells = <0>;
> - };
> -
> dsi0: dsi@fd0c0000 {
> compatible = "cdns,dsi";
> reg = <0x0 0xfd0c0000 0x0 0x1000>;
> diff --git a/Documentation/devicetree/bindings/phy/cdns,dphy.txt b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> new file mode 100644
> index 000000000000..1095bc4e72d9
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> @@ -0,0 +1,20 @@
> +Cadence DPHY
> +============
> +
> +Cadence DPHY block.
> +
> +Required properties:
> +- compatible: should be set to "cdns,dphy".
> +- reg: physical base address and length of the DPHY registers.
> +- clocks: DPHY reference clocks.
> +- clock-names: must contain "psm" and "pll_ref".
> +- #phy-cells: must be set to 0.
> +
> +Example:
> + dphy0: dphy@fd0e0000{
> + compatible = "cdns,dphy";
> + reg = <0x0 0xfd0e0000 0x0 0x1000>;
> + clocks = <&psm_clk>, <&pll_ref_clk>;
> + clock-names = "psm", "pll_ref";
> + #phy-cells = <0>;
> + };
> diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
> index 57fff7de4031..240effa81046 100644
> --- a/drivers/phy/cadence/Kconfig
> +++ b/drivers/phy/cadence/Kconfig
> @@ -1,6 +1,7 @@
> #
> -# Phy driver for Cadence MHDP DisplayPort controller
> +# Phy drivers for Cadence IPs
> #
> +
> config PHY_CADENCE_DP
> tristate "Cadence MHDP DisplayPort PHY driver"
> depends on OF
> @@ -8,3 +9,13 @@ config PHY_CADENCE_DP
> select GENERIC_PHY
> help
> Support for Cadence MHDP DisplayPort PHY.
> +
> +config PHY_CADENCE_DPHY
> + tristate "Cadence D-PHY Support"
> + depends on HAS_IOMEM && OF
> + select GENERIC_PHY
> + select GENERIC_PHY_MIPI_DPHY
> + help
> + Choose this option if you have a Cadence D-PHY in your
> + system. If M is selected, the module will be called
> + cdns-csi.
> diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
> index e5b0a11cf28a..64cb9ea66ceb 100644
> --- a/drivers/phy/cadence/Makefile
> +++ b/drivers/phy/cadence/Makefile
> @@ -1 +1,2 @@
> obj-$(CONFIG_PHY_CADENCE_DP) += phy-cadence-dp.o
> +obj-$(CONFIG_PHY_CADENCE_DPHY) += cdns-dphy.o
> diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
> new file mode 100644
> index 000000000000..a398b401e5d3
> --- /dev/null
> +++ b/drivers/phy/cadence/cdns-dphy.c
> @@ -0,0 +1,459 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright: 2017-2018 Cadence Design Systems, Inc.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +#include <linux/phy/phy.h>
> +#include <linux/phy/phy-mipi-dphy.h>
> +
> +#define REG_WAKEUP_TIME_NS 800
> +#define DPHY_PLL_RATE_HZ 108000000
> +
> +/* DPHY registers */
> +#define DPHY_PMA_CMN(reg) (reg)
> +#define DPHY_PMA_LCLK(reg) (0x100 + (reg))
> +#define DPHY_PMA_LDATA(lane, reg) (0x200 + ((lane) * 0x100) + (reg))
> +#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_CMN_SSM DPHY_PMA_CMN(0x20)
> +#define DPHY_CMN_SSM_EN BIT(0)
> +#define DPHY_CMN_TX_MODE_EN BIT(9)
> +
> +#define DPHY_CMN_PWM DPHY_PMA_CMN(0x40)
> +#define DPHY_CMN_PWM_DIV(x) ((x) << 20)
> +#define DPHY_CMN_PWM_LOW(x) ((x) << 10)
> +#define DPHY_CMN_PWM_HIGH(x) (x)
> +
> +#define DPHY_CMN_FBDIV DPHY_PMA_CMN(0x4c)
> +#define DPHY_CMN_FBDIV_VAL(low, high) (((high) << 11) | ((low) << 22))
> +#define DPHY_CMN_FBDIV_FROM_REG (BIT(10) | BIT(21))
> +
> +#define DPHY_CMN_OPIPDIV DPHY_PMA_CMN(0x50)
> +#define DPHY_CMN_IPDIV_FROM_REG BIT(0)
> +#define DPHY_CMN_IPDIV(x) ((x) << 1)
> +#define DPHY_CMN_OPDIV_FROM_REG BIT(6)
> +#define DPHY_CMN_OPDIV(x) ((x) << 7)
> +
> +#define DPHY_PSM_CFG DPHY_PCS(0x4)
> +#define DPHY_PSM_CFG_FROM_REG BIT(0)
> +#define DPHY_PSM_CLK_DIV(x) ((x) << 1)
> +
> +#define DSI_HBP_FRAME_OVERHEAD 12
> +#define DSI_HSA_FRAME_OVERHEAD 14
> +#define DSI_HFP_FRAME_OVERHEAD 6
> +#define DSI_HSS_VSS_VSE_FRAME_OVERHEAD 4
> +#define DSI_BLANKING_FRAME_OVERHEAD 6
> +#define DSI_NULL_FRAME_OVERHEAD 6
> +#define DSI_EOT_PKT_SIZE 4
> +
> +struct cdns_dphy_cfg {
> + u8 pll_ipdiv;
> + u8 pll_opdiv;
> + u16 pll_fbdiv;
> + unsigned int nlanes;
> +};
> +
> +enum cdns_dphy_clk_lane_cfg {
> + DPHY_CLK_CFG_LEFT_DRIVES_ALL = 0,
> + DPHY_CLK_CFG_LEFT_DRIVES_RIGHT = 1,
> + DPHY_CLK_CFG_LEFT_DRIVES_LEFT = 2,
> + DPHY_CLK_CFG_RIGHT_DRIVES_ALL = 3,
> +};
> +
> +struct cdns_dphy;
> +struct cdns_dphy_ops {
> + int (*probe)(struct cdns_dphy *dphy);
> + void (*remove)(struct cdns_dphy *dphy);
> + void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
> + void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
> + enum cdns_dphy_clk_lane_cfg cfg);
> + void (*set_pll_cfg)(struct cdns_dphy *dphy,
> + const struct cdns_dphy_cfg *cfg);
> + unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
> +};
> +
> +struct cdns_dphy {
> + struct cdns_dphy_cfg cfg;
> + void __iomem *regs;
> + struct clk *psm_clk;
> + struct clk *pll_ref_clk;
> + const struct cdns_dphy_ops *ops;
> + struct phy *phy;
> +};
> +
> +static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
> + struct cdns_dphy_cfg *cfg,
> + struct phy_configure_opts_mipi_dphy *opts,
> + unsigned int *dsi_hfp_ext)
> +{
> + u64 dlane_bps, dlane_bps_max, fbdiv, fbdiv_max, adj_dsi_htotal;
> + unsigned long pll_ref_hz = clk_get_rate(dphy->pll_ref_clk);
> +
> + memset(cfg, 0, sizeof(*cfg));
> +
> + if (pll_ref_hz < 9600000 || pll_ref_hz >= 150000000)
> + return -EINVAL;
> + else if (pll_ref_hz < 19200000)
> + cfg->pll_ipdiv = 1;
> + else if (pll_ref_hz < 38400000)
> + cfg->pll_ipdiv = 2;
> + else if (pll_ref_hz < 76800000)
> + cfg->pll_ipdiv = 4;
> + else
> + cfg->pll_ipdiv = 8;
> +
> + dlane_bps = opts->hs_clk_rate;
> +
> + if (dlane_bps > 2500000000UL || dlane_bps < 160000000UL)
> + return -EINVAL;
> + else if (dlane_bps >= 1250000000)
> + cfg->pll_opdiv = 1;
> + else if (dlane_bps >= 630000000)
> + cfg->pll_opdiv = 2;
> + else if (dlane_bps >= 320000000)
> + cfg->pll_opdiv = 4;
> + else if (dlane_bps >= 160000000)
> + cfg->pll_opdiv = 8;
> +
> + /*
> + * Allow a deviation of 0.2% on the per-lane data rate to try to
> + * recover a potential mismatch between DPI and PPI clks.
> + */
> + dlane_bps_max = dlane_bps + DIV_ROUND_DOWN_ULL(dlane_bps, 500);
> + fbdiv_max = DIV_ROUND_DOWN_ULL(dlane_bps_max * 2 *
> + cfg->pll_opdiv * cfg->pll_ipdiv,
> + pll_ref_hz);
> + fbdiv = DIV_ROUND_UP_ULL(dlane_bps * 2 * cfg->pll_opdiv *
> + cfg->pll_ipdiv,
> + pll_ref_hz);
> +
> + /*
> + * Iterate over all acceptable fbdiv and try to find an adjusted DSI
> + * htotal length providing an exact match.
> + *
> + * Note that we could do something even trickier by relying on the fact
> + * that a new line is not necessarily aligned on a lane boundary, so,
> + * by making adj_dsi_htotal non aligned on a dsi_lanes we can improve a
> + * bit the precision. With this, the step would be
> + *
> + * pll_ref_hz / (2 * opdiv * ipdiv * nlanes)
> + *
> + * instead of
> + *
> + * pll_ref_hz / (2 * opdiv * ipdiv)
> + *
> + * The drawback of this approach is that we would need to make sure the
> + * number or lines is a multiple of the realignment periodicity which is
> + * a function of the number of lanes and the original misalignment. For
> + * example, for NLANES = 4 and HTOTAL % NLANES = 3, it takes 4 lines
> + * to realign on a lane:
> + * LINE 0: expected number of bytes, starts emitting first byte of
> + * LINE 1 on LANE 3
> + * LINE 1: expected number of bytes, starts emitting first 2 bytes of
> + * LINE 2 on LANES 2 and 3
> + * LINE 2: expected number of bytes, starts emitting first 3 bytes of
> + * of LINE 3 on LANES 1, 2 and 3
> + * LINE 3: one byte less, now things are realigned on LANE 0 for LINE 4
> + *
> + * I figured this extra complexity was not worth the benefit, but if
> + * someone really has unfixable mismatch, that would be something to
> + * investigate.
> + */
> + for (; fbdiv <= fbdiv_max; fbdiv++) {
> + u32 rem;
> +
> + /*
> + * Do the division in 2 steps to avoid an overflow on the
> + * divider.
> + */
> + rem = do_div(adj_dsi_htotal, opts->hs_clk_rate);
> + if (rem)
> + continue;
> +
> + rem = do_div(adj_dsi_htotal,
> + cfg->pll_opdiv * cfg->pll_ipdiv * 2 * 8);
> + if (rem)
> + continue;
> +
> + cfg->pll_fbdiv = fbdiv;
> + break;
> + }
> +
> + /* No match, let's just reject the display mode. */
> + if (!cfg->pll_fbdiv)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int cdns_dphy_setup_psm(struct cdns_dphy *dphy)
> +{
> + unsigned long psm_clk_hz = clk_get_rate(dphy->psm_clk);
> + unsigned long psm_div;
> +
> + if (!psm_clk_hz || psm_clk_hz > 100000000)
> + return -EINVAL;
> +
> + psm_div = DIV_ROUND_CLOSEST(psm_clk_hz, 1000000);
> + if (dphy->ops->set_psm_div)
> + dphy->ops->set_psm_div(dphy, psm_div);
> +
> + return 0;
> +}
> +
> +static void cdns_dphy_set_clk_lane_cfg(struct cdns_dphy *dphy,
> + enum cdns_dphy_clk_lane_cfg cfg)
> +{
> + if (dphy->ops->set_clk_lane_cfg)
> + dphy->ops->set_clk_lane_cfg(dphy, cfg);
> +}
> +
> +static void cdns_dphy_set_pll_cfg(struct cdns_dphy *dphy,
> + const struct cdns_dphy_cfg *cfg)
> +{
> + if (dphy->ops->set_pll_cfg)
> + dphy->ops->set_pll_cfg(dphy, cfg);
> +}
> +
> +static unsigned long cdns_dphy_get_wakeup_time_ns(struct cdns_dphy *dphy)
> +{
> + return dphy->ops->get_wakeup_time_ns(dphy);
> +}
> +
> +static unsigned long cdns_dphy_ref_get_wakeup_time_ns(struct cdns_dphy *dphy)
> +{
> + /* Default wakeup time is 800 ns (in a simulated environment). */
> + return 800;
> +}
> +
> +static void cdns_dphy_ref_set_pll_cfg(struct cdns_dphy *dphy,
> + const struct cdns_dphy_cfg *cfg)
> +{
> + u32 fbdiv_low, fbdiv_high;
> +
> + fbdiv_low = (cfg->pll_fbdiv / 4) - 2;
> + fbdiv_high = cfg->pll_fbdiv - fbdiv_low - 2;
> +
> + writel(DPHY_CMN_IPDIV_FROM_REG | DPHY_CMN_OPDIV_FROM_REG |
> + DPHY_CMN_IPDIV(cfg->pll_ipdiv) |
> + DPHY_CMN_OPDIV(cfg->pll_opdiv),
> + dphy->regs + DPHY_CMN_OPIPDIV);
> + writel(DPHY_CMN_FBDIV_FROM_REG |
> + DPHY_CMN_FBDIV_VAL(fbdiv_low, fbdiv_high),
> + dphy->regs + DPHY_CMN_FBDIV);
> + writel(DPHY_CMN_PWM_HIGH(6) | DPHY_CMN_PWM_LOW(0x101) |
> + DPHY_CMN_PWM_DIV(0x8),
> + dphy->regs + DPHY_CMN_PWM);
> +}
> +
> +static void cdns_dphy_ref_set_psm_div(struct cdns_dphy *dphy, u8 div)
> +{
> + writel(DPHY_PSM_CFG_FROM_REG | DPHY_PSM_CLK_DIV(div),
> + dphy->regs + DPHY_PSM_CFG);
> +}
> +
> +/*
> + * 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
> + * to wire things in the SoC.
> + */
> +static const struct cdns_dphy_ops ref_dphy_ops = {
> + .get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
> + .set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
> + .set_psm_div = cdns_dphy_ref_set_psm_div,
> +};
> +
> +static int cdns_dphy_config_from_opts(struct phy *phy,
> + struct phy_configure_opts_mipi_dphy *opts,
> + struct cdns_dphy_cfg *cfg)
> +{
> + struct cdns_dphy *dphy = phy_get_drvdata(phy);
> + unsigned int dsi_hfp_ext = 0;
> + int ret;
> +
> + ret = phy_mipi_dphy_config_validate(opts);
> + if (ret)
> + return ret;
> +
> + ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
> + opts, &dsi_hfp_ext);
> + if (ret)
> + return ret;
> +
> + opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
> +
> + return 0;
> +}
> +
> +static int cdns_dphy_init(struct phy *phy)
> +{
> + struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +
> + clk_prepare_enable(dphy->psm_clk);
> + clk_prepare_enable(dphy->pll_ref_clk);
> +
> + return 0;
> +}
> +
> +static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode,
> + union phy_configure_opts *opts)
> +{
> + struct cdns_dphy_cfg cfg = { 0 };
> +
> + if (mode != PHY_MODE_MIPI_DPHY)
> + return -EINVAL;
> +
> + return cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> +}
> +
> +static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
> +{
> + struct cdns_dphy *dphy = phy_get_drvdata(phy);
> + struct cdns_dphy_cfg cfg = { 0 };
> + int ret;
> +
> + ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> + if (ret)
> + return ret;

Can you explain why you need the same function to be invoked from both validate
and configure callback? I see this to be redundant.

Thanks
Kishon

Next message: David Laight: "RE: [PATCH] slab.h: Avoid using & for logical and of booleans"
Previous message: Chao Fan: "Re: [PATCH v11 3/5] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdlien from kexec"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]