Messages in this thread | | | Date | Thu, 16 Sep 2021 12:22:54 +0200 | From | Paul Kocialkowski <> | Subject | Re: [PATCH v5 2/6] phy: cdns-dphy: Add Rx support |
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Hi,
On Fri 03 Sep 21, 00:25, Pratyush Yadav wrote: > 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 mode in which the DPHY has to be used is selected based on > the compatible.
I just realized that I didn't follow-up on a previous revision on the debate about using the phy sub-mode to distinguish between rx/tx.
I see that you've been using a dedicated compatible, but I'm not sure this is a good fit either. My understanding is that the compatible should describe a group of register-compatible revisions of a hardware component, not how the hardware is used specifically. I guess the distinction between rx/tx falls under the latter rather than the former.
I just sent out a patch in my Allwinner MIPI CSI-2+ISP series adding a specific direction property: - https://lists.infradead.org/pipermail/linux-phy/2021-September/001420.html - https://lists.infradead.org/pipermail/linux-phy/2021-September/001421.html
Which I feel is a more appropriate solution to implement the distinction.
What do you think?
Cheers,
Paul
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com> > > --- > > Changes in v5: > - Use the new cdns_dphy_info to specify PHY ops. > - Re-order include in alphabetical order. > - Make bands const. > - Drop num_bands. > - Make i, lanes unsigned. > - Drop the maximum check in cdns_dphy_rx_get_band_ctrl(). Let the loop > complete and return -EOPNOTSUPP when we reach the end. > - Drop the "rate < bands[i].min_rate" check since the bands are in > ascending order. > - Move data_lane_ctrl to start of function and make it static const. > > Changes in v4: > - Drop the submode parts. Use a different compatible for the Rx ops. > - Make bands and num_bands static. > > Changes in v3: > - Use a table to select the band. > - Use a table to poll the data lane ready bits. > - Multiply the DPHY HS clock rate by 2 to get the bit rate since the > clock is DDR. > > drivers/phy/cadence/cdns-dphy.c | 182 ++++++++++++++++++++++++++++++++ > 1 file changed, 182 insertions(+) > > diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c > index e2c2b27c6539..9a4c1c684e9a 100644 > --- 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/bitfield.h> > #include <linux/bitops.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; > @@ -105,6 +132,20 @@ struct cdns_dphy { > struct phy *phy; > }; > > +struct cdns_dphy_rx_band { > + unsigned int min_rate; > + unsigned int max_rate; > +}; > + > +/* Order of bands is important since the index is the band number. */ > +static const struct cdns_dphy_rx_band bands[] = { > + {80, 100}, {100, 120}, {120, 160}, {160, 200}, {200, 240}, > + {240, 280}, {280, 320}, {320, 360}, {360, 400}, {400, 480}, > + {480, 560}, {560, 640}, {640, 720}, {720, 800}, {800, 880}, > + {880, 1040}, {1040, 1200}, {1200, 1350}, {1350, 1500}, {1500, 1750}, > + {1750, 2000}, {2000, 2250}, {2250, 2500} > +}; > + > static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy, > struct cdns_dphy_cfg *cfg, > struct phy_configure_opts_mipi_dphy *opts, > @@ -360,6 +401,145 @@ static const struct cdns_dphy_info tx_ref_info = { > .tx_ops = &tx_ref_dphy_ops, > }; > > +static int cdns_dphy_rx_power_on(struct phy *phy) > +{ > + struct cdns_dphy *dphy = phy_get_drvdata(phy); > + > + /* 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 phy *phy) > +{ > + struct cdns_dphy *dphy = phy_get_drvdata(phy); > + > + 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, i; > + > + rate = hs_clk_rate / 1000000UL; > + /* Since CSI-2 clock is DDR, the bit rate is twice the clock rate. */ > + rate *= 2; > + > + if (rate < bands[0].min_rate) > + return -EOPNOTSUPP; > + > + for (i = 0; i < ARRAY_SIZE(bands); i++) { > + if (rate < bands[i].max_rate) > + return i; > + } > + > + return -EOPNOTSUPP; > +} > + > +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, > + unsigned int lanes) > +{ > + static const u32 data_lane_ctrl[] = {DPHY_ISO_DL_CTRL_L0, > + DPHY_ISO_DL_CTRL_L1, > + DPHY_ISO_DL_CTRL_L2, > + DPHY_ISO_DL_CTRL_L3}; > + void __iomem *reg = dphy->regs; > + unsigned int i; > + int ret; > + > + /* Data lanes. Minimum one lane is mandatory. */ > + 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; > + > + for (i = 0; i < lanes; i++) { > + ret = cdns_dphy_rx_wait_for_bit(reg + data_lane_ctrl[i], > + DPHY_ISO_LANE_READY_BIT); > + if (ret) > + return ret; > + } > + > + return 0; > +} > + > +static int cdns_dphy_rx_configure(struct phy *phy, > + union phy_configure_opts *opts) > +{ > + struct cdns_dphy *dphy = phy_get_drvdata(phy); > + 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 phy *phy, enum phy_mode mode, > + int submode, union phy_configure_opts *opts) > +{ > + int ret; > + > + if (mode != PHY_MODE_MIPI_DPHY) > + 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 phy_ops rx_ref_phy_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, > +}; > + > +static const struct cdns_dphy_info rx_ref_info = { > + .phy_ops = &rx_ref_phy_ops, > +}; > + > static int cdns_dphy_probe(struct platform_device *pdev) > { > struct phy_provider *phy_provider; > @@ -417,6 +597,7 @@ static int cdns_dphy_remove(struct platform_device *pdev) > > static const struct of_device_id cdns_dphy_of_match[] = { > { .compatible = "cdns,dphy", .data = &tx_ref_info }, > + { .compatible = "cdns,dphy-rx", .data = &rx_ref_info }, > { /* sentinel */ }, > }; > MODULE_DEVICE_TABLE(of, cdns_dphy_of_match); > @@ -432,5 +613,6 @@ 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"); > -- > 2.33.0 >
-- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com [unhandled content-type:application/pgp-signature] | |