Re: [PATCH v3] staging: Add Xilinx Clocking Wizard driver
From: Laurent Pinchart
Date: Mon Oct 06 2014 - 06:54:39 EST
Hi Sören,
Thank you for the patch.
On Thursday 02 October 2014 09:13:35 Soren Brinkmann wrote:
> Add a driver for the Xilinx Clocking Wizard soft IP. The clocking wizard
> provides an AXI interface to dynamically reconfigure the clocking
> resources of Xilinx FPGAs.
>
> Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
For the DT bindings,
Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> v3:
> - allow building the driver as module
> - make speed grade positive
> - document valid values for speed-grade DT property
> v2:
> - implement dev_pm_ops
> - don't use array for clock inputs
> - add more information in error output
> - fix style issues
> - fix error path
> ---
> drivers/staging/Kconfig | 2 +
> drivers/staging/Makefile | 1 +
> drivers/staging/clocking-wizard/Kconfig | 9 +
> drivers/staging/clocking-wizard/Makefile | 1 +
> drivers/staging/clocking-wizard/TODO | 12 +
> .../clocking-wizard/clk-xlnx-clock-wizard.c | 335 ++++++++++++++++++
> drivers/staging/clocking-wizard/dt-binding.txt | 30 ++
> 7 files changed, 390 insertions(+)
> create mode 100644 drivers/staging/clocking-wizard/Kconfig
> create mode 100644 drivers/staging/clocking-wizard/Makefile
> create mode 100644 drivers/staging/clocking-wizard/TODO
> create mode 100644 drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c
> create mode 100644 drivers/staging/clocking-wizard/dt-binding.txt
>
> diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
> index 35b494f5667f..7daf345bec0e 100644
> --- a/drivers/staging/Kconfig
> +++ b/drivers/staging/Kconfig
> @@ -118,4 +118,6 @@ source "drivers/staging/skein/Kconfig"
>
> source "drivers/staging/unisys/Kconfig"
>
> +source "drivers/staging/clocking-wizard/Kconfig"
> +
> endif # STAGING
> diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
> index e66a5dbd9b02..03fec7f981cc 100644
> --- a/drivers/staging/Makefile
> +++ b/drivers/staging/Makefile
> @@ -51,3 +51,4 @@ obj-$(CONFIG_GS_FPGABOOT) += gs_fpgaboot/
> obj-$(CONFIG_BT_NOKIA_H4P) += nokia_h4p/
> obj-$(CONFIG_CRYPTO_SKEIN) += skein/
> obj-$(CONFIG_UNISYSSPAR) += unisys/
> +obj-$(CONFIG_COMMON_CLK_XLNX_CLKWZRD) += clocking-wizard/
> diff --git a/drivers/staging/clocking-wizard/Kconfig
> b/drivers/staging/clocking-wizard/Kconfig new file mode 100644
> index 000000000000..357af02c562c
> --- /dev/null
> +++ b/drivers/staging/clocking-wizard/Kconfig
> @@ -0,0 +1,9 @@
> +#
> +# Xilinx Clocking Wizard Driver
> +#
> +
> +config COMMON_CLK_XLNX_CLKWZRD
> + tristate "Xilinx Clocking Wizard"
> + depends on COMMON_CLK && OF
> + ---help---
> + Support for the Xilinx Clocking Wizard IP core clock generator.
> diff --git a/drivers/staging/clocking-wizard/Makefile
> b/drivers/staging/clocking-wizard/Makefile new file mode 100644
> index 000000000000..5ad352f521fe
> --- /dev/null
> +++ b/drivers/staging/clocking-wizard/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_COMMON_CLK_XLNX_CLKWZRD) += clk-xlnx-clock-wizard.o
> diff --git a/drivers/staging/clocking-wizard/TODO
> b/drivers/staging/clocking-wizard/TODO new file mode 100644
> index 000000000000..ebe99db7d153
> --- /dev/null
> +++ b/drivers/staging/clocking-wizard/TODO
> @@ -0,0 +1,12 @@
> +TODO:
> + - support for fractional multiplier
> + - support for fractional divider (output 0 only)
> + - support for set_rate() operations (may benefit from Stephen Boyd's
> + refactoring of the clk primitives: https://lkml.org/lkml/2014/9/5/766)
> + - review arithmetic
> + - overflow after multiplication?
> + - maximize accuracy before divisions
> +
> +Patches to:
> + Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> + Sören Brinkmann <soren.brinkmann@xxxxxxxxxx>
> diff --git a/drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c
> b/drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c new file mode
> 100644
> index 000000000000..b8d89525bffd
> --- /dev/null
> +++ b/drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c
> @@ -0,0 +1,335 @@
> +/*
> + * Xilinx 'Clocking Wizard' driver
> + *
> + * Copyright (C) 2013 - 2014 Xilinx
> + *
> + * Sören Brinkmann <soren.brinkmann@xxxxxxxxxx>
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License v2 as published by
> + * the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/clk-provider.h>
> +#include <linux/slab.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +
> +#define WZRD_NUM_OUTPUTS 7
> +#define WZRD_ACLK_MAX_FREQ 250000000UL
> +
> +#define WZRD_CLK_CFG_REG(n) (0x200 + 4 * n)
> +
> +#define WZRD_CLkOUT0_FRAC_EN BIT(18)
> +#define WZRD_CLkFBOUT_FRAC_EN BIT(26)
> +
> +#define WZRD_CLKFBOUT_MULT_SHIFT 8
> +#define WZRD_CLKFBOUT_MULT_MASK (0xff << WZRD_CLKFBOUT_MULT_SHIFT)
> +#define WZRD_DIVCLK_DIVIDE_SHIFT 0
> +#define WZRD_DIVCLK_DIVIDE_MASK (0xff << WZRD_DIVCLK_DIVIDE_SHIFT)
> +#define WZRD_CLKOUT_DIVIDE_SHIFT 0
> +#define WZRD_CLKOUT_DIVIDE_MASK (0xff << WZRD_DIVCLK_DIVIDE_SHIFT)
> +
> +enum clk_wzrd_int_clks {
> + wzrd_clk_mul,
> + wzrd_clk_mul_div,
> + wzrd_clk_int_max
> +};
> +
> +/**
> + * struct clk_wzrd:
> + * @clk_data: Clock data
> + * @nb: Notifier block
> + * @base: Memory base
> + * @clk_in1: Handle to input clock 'clk_in1'
> + * @axi_clk: Handle to input clock 's_axi_aclk'
> + * @clks_internal: Internal clocks
> + * @clkout: Output clocks
> + * @speed_grade: Speed grade of the device
> + * @suspended: Flag indicating power state of the device
> + */
> +struct clk_wzrd {
> + struct clk_onecell_data clk_data;
> + struct notifier_block nb;
> + void __iomem *base;
> + struct clk *clk_in1;
> + struct clk *axi_clk;
> + struct clk *clks_internal[wzrd_clk_int_max];
> + struct clk *clkout[WZRD_NUM_OUTPUTS];
> + int speed_grade;
> + bool suspended;
> +};
> +#define to_clk_wzrd(_nb) container_of(_nb, struct clk_wzrd, nb)
> +
> +/* maximum frequencies for input/output clocks per speed grade */
> +static const unsigned long clk_wzrd_max_freq[] = {
> + 800000000UL,
> + 933000000UL,
> + 1066000000UL
> +};
> +
> +static int clk_wzrd_clk_notifier(struct notifier_block *nb, unsigned long
> event, + void *data)
> +{
> + unsigned long max;
> + struct clk_notifier_data *ndata = data;
> + struct clk_wzrd *clk_wzrd = to_clk_wzrd(nb);
> +
> + if (clk_wzrd->suspended)
> + return NOTIFY_OK;
> +
> + if (ndata->clk == clk_wzrd->clk_in1)
> + max = clk_wzrd_max_freq[clk_wzrd->speed_grade - 1];
> + if (ndata->clk == clk_wzrd->axi_clk)
> + max = WZRD_ACLK_MAX_FREQ;
> +
> + switch (event) {
> + case PRE_RATE_CHANGE:
> + if (ndata->new_rate > max)
> + return NOTIFY_BAD;
> + return NOTIFY_OK;
> + case POST_RATE_CHANGE:
> + case ABORT_RATE_CHANGE:
> + default:
> + return NOTIFY_DONE;
> + }
> +}
> +
> +static int __maybe_unused clk_wzrd_suspend(struct device *dev)
> +{
> + struct clk_wzrd *clk_wzrd = dev_get_drvdata(dev);
> +
> + clk_disable_unprepare(clk_wzrd->axi_clk);
> + clk_wzrd->suspended = true;
> +
> + return 0;
> +}
> +
> +static int __maybe_unused clk_wzrd_resume(struct device *dev)
> +{
> + int ret;
> + struct clk_wzrd *clk_wzrd = dev_get_drvdata(dev);
> +
> + ret = clk_prepare_enable(clk_wzrd->axi_clk);
> + if (ret) {
> + dev_err(dev, "unable to enable s_axi_aclk\n");
> + return ret;
> + }
> +
> + clk_wzrd->suspended = false;
> +
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(clk_wzrd_dev_pm_ops, clk_wzrd_suspend,
> + clk_wzrd_resume);
> +
> +static int clk_wzrd_probe(struct platform_device *pdev)
> +{
> + int i, ret;
> + u32 reg;
> + unsigned long rate;
> + const char *clk_name;
> + struct clk_wzrd *clk_wzrd;
> + struct resource *mem;
> + struct device_node *np = pdev->dev.of_node;
> +
> + clk_wzrd = devm_kzalloc(&pdev->dev, sizeof(*clk_wzrd), GFP_KERNEL);
> + if (!clk_wzrd)
> + return -ENOMEM;
> + platform_set_drvdata(pdev, clk_wzrd);
> +
> + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + clk_wzrd->base = devm_ioremap_resource(&pdev->dev, mem);
> + if (IS_ERR(clk_wzrd->base))
> + return PTR_ERR(clk_wzrd->base);
> +
> + ret = of_property_read_u32(np, "speed-grade", &clk_wzrd->speed_grade);
> + if (!ret) {
> + if (clk_wzrd->speed_grade < 1 || clk_wzrd->speed_grade > 3) {
> + dev_warn(&pdev->dev, "invalid speed grade '%d'\n",
> + clk_wzrd->speed_grade);
> + clk_wzrd->speed_grade = 0;
> + }
> + }
> +
> + clk_wzrd->clk_in1 = devm_clk_get(&pdev->dev, "clk_in1");
> + if (IS_ERR(clk_wzrd->clk_in1)) {
> + if (clk_wzrd->clk_in1 != ERR_PTR(-EPROBE_DEFER))
> + dev_err(&pdev->dev, "clk_in1 not found\n");
> + return PTR_ERR(clk_wzrd->clk_in1);
> + }
> +
> + clk_wzrd->axi_clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
> + if (IS_ERR(clk_wzrd->axi_clk)) {
> + if (clk_wzrd->axi_clk != ERR_PTR(-EPROBE_DEFER))
> + dev_err(&pdev->dev, "s_axi_aclk not found\n");
> + return PTR_ERR(clk_wzrd->axi_clk);
> + }
> + ret = clk_prepare_enable(clk_wzrd->axi_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "enabling s_axi_aclk failed\n");
> + return ret;
> + }
> + rate = clk_get_rate(clk_wzrd->axi_clk);
> + if (rate > WZRD_ACLK_MAX_FREQ) {
> + dev_err(&pdev->dev, "s_axi_aclk frequency (%lu) too high\n",
> + rate);
> + ret = -EINVAL;
> + goto err_disable_clk;
> + }
> +
> + /* we don't support fractional div/mul yet */
> + reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
> + WZRD_CLkFBOUT_FRAC_EN;
> + reg |= readl(clk_wzrd->base + WZRD_CLK_CFG_REG(2)) &
> + WZRD_CLkOUT0_FRAC_EN;
> + if (reg)
> + dev_warn(&pdev->dev, "fractional div/mul not supported\n");
> +
> + /* register multiplier */
> + reg = (readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
> + WZRD_CLKFBOUT_MULT_MASK) >> WZRD_CLKFBOUT_MULT_SHIFT;
> + clk_name = kasprintf(GFP_KERNEL, "%s_mul", dev_name(&pdev->dev));
> + if (!clk_name) {
> + ret = -ENOMEM;
> + goto err_disable_clk;
> + }
> + clk_wzrd->clks_internal[wzrd_clk_mul] = clk_register_fixed_factor(
> + &pdev->dev, clk_name,
> + __clk_get_name(clk_wzrd->clk_in1),
> + 0, reg, 1);
> + kfree(clk_name);
> + if (IS_ERR(clk_wzrd->clks_internal[wzrd_clk_mul])) {
> + dev_err(&pdev->dev, "unable to register fixed-factor clock\n");
> + ret = PTR_ERR(clk_wzrd->clks_internal[wzrd_clk_mul]);
> + goto err_disable_clk;
> + }
> +
> + /* register div */
> + reg = (readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
> + WZRD_DIVCLK_DIVIDE_MASK) >> WZRD_DIVCLK_DIVIDE_SHIFT;
> + clk_name = kasprintf(GFP_KERNEL, "%s_mul_div", dev_name(&pdev->dev));
> + clk_wzrd->clks_internal[wzrd_clk_mul_div] = clk_register_fixed_factor(
> + &pdev->dev, clk_name,
> + __clk_get_name(clk_wzrd->clks_internal[wzrd_clk_mul]),
> + 0, 1, reg);
> + if (IS_ERR(clk_wzrd->clks_internal[wzrd_clk_mul_div])) {
> + dev_err(&pdev->dev, "unable to register divider clock\n");
> + ret = PTR_ERR(clk_wzrd->clks_internal[wzrd_clk_mul_div]);
> + goto err_rm_int_clk;
> + }
> +
> + /* register div per output */
> + for (i = WZRD_NUM_OUTPUTS - 1; i >= 0 ; i--) {
> + const char *clkout_name;
> + if (of_property_read_string_index(np, "clock-output-names", i,
> + &clkout_name)) {
> + dev_err(&pdev->dev,
> + "clock output name not specified\n");
> + ret = -EINVAL;
> + goto err_rm_int_clks;
> + }
> + reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(2) + i * 12);
> + reg &= WZRD_CLKOUT_DIVIDE_MASK;
> + reg >>= WZRD_CLKOUT_DIVIDE_SHIFT;
> + clk_wzrd->clkout[i] = clk_register_fixed_factor(&pdev->dev,
> + clkout_name, clk_name, 0, 1, reg);
> + if (IS_ERR(clk_wzrd->clkout[i])) {
> + int j;
> + for (j = i + 1; j < WZRD_NUM_OUTPUTS; j++)
> + clk_unregister(clk_wzrd->clkout[j]);
> + dev_err(&pdev->dev,
> + "unable to register divider clock\n");
> + ret = PTR_ERR(clk_wzrd->clkout[i]);
> + goto err_rm_int_clks;
> + }
> + }
> +
> + kfree(clk_name);
> +
> + clk_wzrd->clk_data.clks = clk_wzrd->clkout;
> + clk_wzrd->clk_data.clk_num = ARRAY_SIZE(clk_wzrd->clkout);
> + of_clk_add_provider(np, of_clk_src_onecell_get, &clk_wzrd->clk_data);
> +
> + if (clk_wzrd->speed_grade) {
> + clk_wzrd->nb.notifier_call = clk_wzrd_clk_notifier;
> +
> + ret = clk_notifier_register(clk_wzrd->clk_in1,
> + &clk_wzrd->nb);
> + if (ret)
> + dev_warn(&pdev->dev,
> + "unable to register clock notifier\n");
> +
> + ret = clk_notifier_register(clk_wzrd->axi_clk, &clk_wzrd->nb);
> + if (ret)
> + dev_warn(&pdev->dev,
> + "unable to register clock notifier\n");
> + }
> +
> + return 0;
> +
> +err_rm_int_clks:
> + clk_unregister(clk_wzrd->clks_internal[1]);
> +err_rm_int_clk:
> + kfree(clk_name);
> + clk_unregister(clk_wzrd->clks_internal[0]);
> +err_disable_clk:
> + clk_disable_unprepare(clk_wzrd->axi_clk);
> +
> + return ret;
> +}
> +
> +static int clk_wzrd_remove(struct platform_device *pdev)
> +{
> + int i;
> + struct clk_wzrd *clk_wzrd = platform_get_drvdata(pdev);
> +
> + of_clk_del_provider(pdev->dev.of_node);
> +
> + for (i = 0; i < WZRD_NUM_OUTPUTS; i++)
> + clk_unregister(clk_wzrd->clkout[i]);
> + for (i = 0; i < wzrd_clk_int_max; i++)
> + clk_unregister(clk_wzrd->clks_internal[i]);
> +
> + if (clk_wzrd->speed_grade) {
> + clk_notifier_unregister(clk_wzrd->axi_clk, &clk_wzrd->nb);
> + clk_notifier_unregister(clk_wzrd->clk_in1, &clk_wzrd->nb);
> + }
> +
> + clk_disable_unprepare(clk_wzrd->axi_clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id clk_wzrd_ids[] = {
> + { .compatible = "xlnx,clocking-wizard" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, clk_wzrd_ids);
> +
> +static struct platform_driver clk_wzrd_driver = {
> + .driver = {
> + .name = "clk-wizard",
> + .of_match_table = clk_wzrd_ids,
> + .pm = &clk_wzrd_dev_pm_ops,
> + },
> + .probe = clk_wzrd_probe,
> + .remove = clk_wzrd_remove,
> +};
> +module_platform_driver(clk_wzrd_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xxxxxxxxxx");
> +MODULE_DESCRIPTION("Driver for the Xilinx Clocking Wizard IP core");
> diff --git a/drivers/staging/clocking-wizard/dt-binding.txt
> b/drivers/staging/clocking-wizard/dt-binding.txt new file mode 100644
> index 000000000000..723271e93316
> --- /dev/null
> +++ b/drivers/staging/clocking-wizard/dt-binding.txt
> @@ -0,0 +1,30 @@
> +Binding for Xilinx Clocking Wizard IP Core
> +
> +This binding uses the common clock binding[1]. Details about the devices
> can be +found in the product guide[2].
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> +[2] Clocking Wizard Product Guide
> +http://www.xilinx.com/support/documentation/ip_documentation/clk_wiz/v5_1/p
> g065-clk-wiz.pdf +
> +Required properties:
> + - compatible: Must be 'xlnx,clocking-wizard'
> + - reg: Base and size of the cores register space
> + - clocks: Handle to input clock
> + - clock-names: Tuple containing 'clk_in1' and 's_axi_aclk'
> + - clock-output-names: Names for the output clocks
> +
> +Optional properties:
> + - speed-grade: Speed grade of the device (valid values are 1..3)
> +
> +Example:
> + clock-generator@40040000 {
> + reg = <0x40040000 0x1000>;
> + compatible = "xlnx,clocking-wizard";
> + speed-grade = <1>;
> + clock-names = "clk_in1", "s_axi_aclk";
> + clocks = <&clkc 15>, <&clkc 15>;
> + clock-output-names = "clk_out0", "clk_out1", "clk_out2",
> + "clk_out3", "clk_out4", "clk_out5",
> + "clk_out6", "clk_out7";
> + };
--
Regards,
Laurent Pinchart
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