Re: [PATCH v5 1/2] clk: zynq: Add clock wizard driver

[Sean Anderson <sean.anderson@seco.com>]

On 6/10/21 6:44 AM, Zhengxun Li wrote:
 > Hi,
 >
 > Sean Anderson <sean.anderson@seco.com> 於 2021年6月4日 週五 下午2:22寫道：
 >>
 >>
 >>
 >> On 6/4/21 1:05 PM, Zhengxun wrote:
 >>> The Clocking Wizard IP supports clock circuits customized
 >>> to your clocking requirements. The wizard support for
 >>> dynamically reconfiguring the clocking primitives for
 >>> Multiply, Divide, Phase Shift/Offset, or Duty Cycle.
 >>>
 >>> Limited by U-Boot clk uclass without set_phase API, this
 >>> patch only provides set_rate to modify the frequency.
 >>>
 >>> Signed-off-by: Zhengxun <zhengxunli.mxic@gmail.com>
 >>> ---
 >>>    drivers/clk/Kconfig                 |   9 ++
 >>>    drivers/clk/Makefile                |   1 +
 >>>    drivers/clk/clk-xlnx-clock-wizard.c | 186 ++++++++++++++++++++++++++++
 >>>    3 files changed, 196 insertions(+)
 >>>    create mode 100644 drivers/clk/clk-xlnx-clock-wizard.c
 >>>
 >>> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
 >>> index 40a5a5dd88..59922fc88e 100644
 >>> --- a/drivers/clk/Kconfig
 >>> +++ b/drivers/clk/Kconfig
 >>> @@ -128,6 +128,15 @@ config CLK_ZYNQ
 >>>          This clock driver adds support for clock related settings for
 >>>          Zynq platform.
 >>>
 >>> +config CLK_XLNX_CLKWZRD
 >>> +     bool "Xilinx Clocking Wizard"
 >>> +     depends on CLK
 >>> +     help
 >>> +       Support for the Xilinx Clocking Wizard IP core clock generator.
 >>> +       Adds support for clocking wizard and compatible.
 >>> +       This driver supports the Xilinx clocking wizard programmable clock
 >>> +       synthesizer.
 >>
 >> Please modify this description in accordance with my comments from last revision.
 >
 > Oops, I misunderstood your information and thought I needed to add the
 > dts binding
 > to tell how to use the clock wizard. So in this state, I need to add a
 > comment here or
 > create another comment to describe the clock wizard?

The current description states the same thing three times. It should
state this once. In addition, it should note any quirks of the driver or
device. For example, it might be prudent to note that this is a soft
device, or that you don't support setting the phase. For some good
examples, see drivers/clk/at91/Kconfig.

--Sean

 >
 >>> +
 >>>    config CLK_ZYNQMP
 >>>        bool "Enable clock driver support for ZynqMP"
 >>>        depends on ARCH_ZYNQMP
 >>> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
 >>> index 645709b855..4fcc33953a 100644
 >>> --- a/drivers/clk/Makefile
 >>> +++ b/drivers/clk/Makefile
 >>> @@ -43,6 +43,7 @@ obj-$(CONFIG_CLK_UNIPHIER) += uniphier/
 >>>    obj-$(CONFIG_CLK_VEXPRESS_OSC) += clk_vexpress_osc.o
 >>>    obj-$(CONFIG_CLK_ZYNQ) += clk_zynq.o
 >>>    obj-$(CONFIG_CLK_ZYNQMP) += clk_zynqmp.o
 >>> +obj-$(CONFIG_CLK_XLNX_CLKWZRD) += clk-xlnx-clock-wizard.o
 >>>    obj-$(CONFIG_ICS8N3QV01) += ics8n3qv01.o
 >>>    obj-$(CONFIG_MACH_PIC32) += clk_pic32.o
 >>>    obj-$(CONFIG_SANDBOX) += clk_sandbox.o
 >>> diff --git a/drivers/clk/clk-xlnx-clock-wizard.c b/drivers/clk/clk-xlnx-clock-wizard.c
 >>> new file mode 100644
 >>> index 0000000000..70ee3af107
 >>> --- /dev/null
 >>> +++ b/drivers/clk/clk-xlnx-clock-wizard.c
 >>> @@ -0,0 +1,186 @@
 >>> +// SPDX-License-Identifier: GPL-2.0
 >>> +/*
 >>> + * Xilinx 'Clocking Wizard' driver
 >>> + *
 >>> + * Copyright (c) 2021 Macronix Inc.
 >>> + *
 >>> + * Author: Zhengxun Li <zhengxunli@mxic.com.tw>
 >>> + */
 >>> +
 >>> +#include <common.h>
 >>> +#include <clk-uclass.h>
 >>> +#include <dm.h>
 >>> +#include <div64.h>
 >>> +#include <dm/device_compat.h>
 >>> +#include <linux/iopoll.h>
 >>> +
 >>> +#include <linux/bitfield.h>
 >>> +
 >>> +#define SRR                  0x0
 >>> +
 >>> +#define SR                   0x4
 >>> +#define SR_LOCKED            BIT(0)
 >>> +
 >>> +#define CCR(x)                       (0x200 + ((x) * 4))
 >>> +
 >>> +#define FBOUT_CFG            CCR(0)
 >>> +#define FBOUT_DIV(x)         (x)
 >>> +#define FBOUT_DIV_MASK               GENMASK(7, 0)
 >>> +#define FBOUT_GET_DIV(x)     FIELD_GET(FBOUT_DIV_MASK, x)
 >>> +#define FBOUT_MUL(x)         ((x) << 8)
 >>> +#define FBOUT_MUL_MASK               GENMASK(15, 8)
 >>> +#define FBOUT_GET_MUL(x)     FIELD_GET(FBOUT_MUL_MASK, x)
 >>> +#define FBOUT_FRAC(x)                ((x) << 16)
 >>> +#define FBOUT_FRAC_MASK              GENMASK(25, 16)
 >>> +#define FBOUT_GET_FRAC(x)    FIELD_GET(FBOUT_FRAC_MASK, x)
 >>> +#define FBOUT_FRAC_EN                BIT(26)
 >>> +
 >>> +#define FBOUT_PHASE          CCR(1)
 >>> +
 >>> +#define OUT_CFG(x)           CCR(2 + ((x) * 3))
 >>> +#define OUT_DIV(x)           (x)
 >>> +#define OUT_DIV_MASK         GENMASK(7, 0)
 >>> +#define OUT_GET_DIV(x)               FIELD_GET(OUT_DIV_MASK, x)
 >>> +#define OUT_FRAC(x)          ((x) << 8)
 >>> +#define OUT_GET_MASK         GENMASK(17, 8)
 >>> +#define OUT_GET_FRAC(x)              FIELD_GET(OUT_GET_MASK, x)
 >>> +#define OUT_FRAC_EN          BIT(18)
 >>> +
 >>> +#define OUT_PHASE(x)         CCR(3 + ((x) * 3))
 >>> +#define OUT_DUTY(x)          CCR(4 + ((x) * 3))
 >>> +
 >>> +#define CTRL                 CCR(23)
 >>> +#define CTRL_SEN             BIT(2)
 >>> +#define CTRL_SADDR           BIT(1)
 >>> +#define CTRL_LOAD            BIT(0)
 >>> +
 >>> +/**
 >>> + * struct clkwzrd - Clock wizard private data structure
 >>> + *
 >>> + * @base:            memory base
 >>> + * @vco_clk:         voltage-controlled oscillator frequency
 >>> + *
 >>> + */
 >>> +struct clkwzd {
 >>> +     void *base;
 >>> +     u64 vco_clk;
 >>> +};
 >>> +
 >>> +struct clkwzd_plat {
 >>> +     fdt_addr_t addr;
 >>> +};
 >>> +
 >>> +static int clk_wzrd_enable(struct clk *clk)
 >>> +{
 >>> +     struct clkwzd *priv = dev_get_priv(clk->dev);
 >>> +     int ret;
 >>> +     u32 val;
 >>> +
 >>> +     ret = readl_poll_sleep_timeout(priv->base + SR, val, val & SR_LOCKED,
 >>> +                                    1, 100);
 >>> +     if (!ret) {
 >>> +             writel(CTRL_SEN | CTRL_SADDR | CTRL_LOAD, priv->base + CTRL);
 >>> +             writel(CTRL_SADDR, priv->base + CTRL);
 >>> +             ret = readl_poll_sleep_timeout(priv->base + SR, val,
 >>> +                                            val & SR_LOCKED, 1, 100);
 >>> +     }
 >>> +
 >>> +     return ret;
 >>> +}
 >>> +
 >>> +static unsigned long clk_wzrd_set_rate(struct clk *clk, ulong rate)
 >>> +{
 >>> +     struct clkwzd *priv = dev_get_priv(clk->dev);
 >>> +     u64 div;
 >>> +     u32 cfg;
 >>> +
 >>> +     /* Get output clock divide value */
 >>> +     div = DIV_ROUND_DOWN_ULL(priv->vco_clk * 1000, rate);
 >>> +     if (div < 1000 || div > 255999)
 >>> +             return -EINVAL;
 >>> +
 >>> +     cfg = OUT_DIV((u32)div / 1000);
 >>> +
 >>> +     writel(cfg, priv->base + OUT_CFG(clk->id));
 >>> +
 >>> +     return 0;
 >>> +}
 >>> +
 >>> +static struct clk_ops clk_wzrd_ops = {
 >>> +     .enable = clk_wzrd_enable,
 >>> +     .set_rate = clk_wzrd_set_rate,
 >>> +};
 >>> +
 >>> +static int clk_wzrd_probe(struct udevice *dev)
 >>> +{
 >>> +     struct clkwzd_plat *plat = dev_get_plat(dev);
 >>> +     struct clkwzd *priv = dev_get_priv(dev);
 >>> +     struct clk clk_in1;
 >>> +     u64 clock, vco_clk;
 >>> +     u32 cfg;
 >>> +     int ret;
 >>> +
 >>> +     priv->base = (void *)plat->addr;
 >>> +
 >>> +     ret = clk_get_by_name(dev, "clk_in1", &clk_in1);
 >>> +     if (ret < 0) {
 >>> +             dev_err(dev, "failed to get clock\n");
 >>> +             return ret;
 >>> +     }
 >>> +
 >>> +     clock = clk_get_rate(&clk_in1);
 >>> +     if (IS_ERR_VALUE(clock)) {
 >>> +             dev_err(dev, "failed to get rate\n");
 >>> +             return clock;
 >>> +     }
 >>> +
 >>> +     ret = clk_enable(&clk_in1);
 >>> +     if (ret) {
 >>> +             dev_err(dev, "failed to enable clock\n");
 >>> +             clk_free(&clk_in1);
 >>> +             return ret;
 >>> +     }
 >>> +
 >>> +     /* Read clock configuration registers */
 >>> +     cfg = readl(priv->base + FBOUT_CFG);
 >>> +
 >>> +     /* Recalculate VCO rate */
 >>> +     if (cfg & FBOUT_FRAC_EN)
 >>> +             vco_clk = DIV_ROUND_DOWN_ULL(clock *
 >>> +                                          ((FBOUT_GET_MUL(cfg) * 1000) +
 >>> +                                           FBOUT_GET_FRAC(cfg)),
 >>> +                                          1000);
 >>> +     else
 >>> +             vco_clk = clock * FBOUT_GET_MUL(cfg);
 >>> +
 >>> +     priv->vco_clk = DIV_ROUND_DOWN_ULL(vco_clk, FBOUT_GET_DIV(cfg));
 >>> +
 >>> +     return 0;
 >>> +}
 >>> +
 >>> +static int clk_wzrd_of_to_plat(struct udevice *dev)
 >>> +{
 >>> +     struct clkwzd_plat *plat = dev_get_plat(dev);
 >>> +
 >>> +     plat->addr = dev_read_addr(dev);
 >>> +     if (plat->addr == FDT_ADDR_T_NONE)
 >>> +             return -EINVAL;
 >>> +
 >>> +     return 0;
 >>> +}
 >>> +
 >>> +static const struct udevice_id clk_wzrd_ids[] = {
 >>> +     { .compatible = "xlnx,clocking-wizard" },
 >>> +     { /* sentinel */ }
 >>> +};
 >>> +
 >>> +U_BOOT_DRIVER(clk_wzrd) = {
 >>> +     .name = "zynq-clk-wizard",
 >>> +     .id = UCLASS_CLK,
 >>> +     .of_match = clk_wzrd_ids,
 >>> +     .ops = &clk_wzrd_ops,
 >>> +     .probe = clk_wzrd_probe,
 >>> +     .of_to_plat = clk_wzrd_of_to_plat,
 >>> +     .priv_auto = sizeof(struct clkwzd),
 >>> +     .plat_auto = sizeof(struct clkwzd_plat),
 >>> +};
 >>>
 >>
 >> With that fixed,
 >>
 >> Reviewed-by: Sean Anderson <sean.anderson@seco.com>
 >
 > Thanks,
 > Zhengxun
 >