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![Liu Ying](/assets/img/avatar_default.png)
Simple Power-Managed bus controller may need functional clock(s) to be enabled before child devices connected to the bus can be accessed. Get the clock(s) as a bulk and enable/disable the clock(s) when the bus is being power managed. One example is that Freescale i.MX8qxp pixel link MSI bus controller needs MSI clock and AHB clock to be enabled before accessing child devices. Signed-off-by: Liu Ying <victor.liu@nxp.com> Tested-by: Maxim Kochetkov <fido_max@inbox.ru> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://lore.kernel.org/r/20221226031417.1056745-1-victor.liu@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
141 lines
3.8 KiB
C
141 lines
3.8 KiB
C
/*
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* Simple Power-Managed Bus Driver
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*
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* Copyright (C) 2014-2015 Glider bvba
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/clk.h>
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#include <linux/module.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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struct simple_pm_bus {
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struct clk_bulk_data *clks;
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int num_clks;
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};
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static int simple_pm_bus_probe(struct platform_device *pdev)
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{
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const struct device *dev = &pdev->dev;
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const struct of_dev_auxdata *lookup = dev_get_platdata(dev);
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struct device_node *np = dev->of_node;
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const struct of_device_id *match;
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struct simple_pm_bus *bus;
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/*
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* Allow user to use driver_override to bind this driver to a
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* transparent bus device which has a different compatible string
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* that's not listed in simple_pm_bus_of_match. We don't want to do any
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* of the simple-pm-bus tasks for these devices, so return early.
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*/
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if (pdev->driver_override)
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return 0;
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match = of_match_device(dev->driver->of_match_table, dev);
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/*
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* These are transparent bus devices (not simple-pm-bus matches) that
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* have their child nodes populated automatically. So, don't need to
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* do anything more. We only match with the device if this driver is
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* the most specific match because we don't want to incorrectly bind to
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* a device that has a more specific driver.
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*/
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if (match && match->data) {
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if (of_property_match_string(np, "compatible", match->compatible) == 0)
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return 0;
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else
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return -ENODEV;
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}
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bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
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if (!bus)
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return -ENOMEM;
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bus->num_clks = devm_clk_bulk_get_all(&pdev->dev, &bus->clks);
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if (bus->num_clks < 0)
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return dev_err_probe(&pdev->dev, bus->num_clks, "failed to get clocks\n");
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dev_set_drvdata(&pdev->dev, bus);
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dev_dbg(&pdev->dev, "%s\n", __func__);
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pm_runtime_enable(&pdev->dev);
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if (np)
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of_platform_populate(np, NULL, lookup, &pdev->dev);
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return 0;
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}
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static int simple_pm_bus_remove(struct platform_device *pdev)
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{
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const void *data = of_device_get_match_data(&pdev->dev);
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if (pdev->driver_override || data)
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return 0;
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dev_dbg(&pdev->dev, "%s\n", __func__);
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pm_runtime_disable(&pdev->dev);
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return 0;
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}
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static int simple_pm_bus_runtime_suspend(struct device *dev)
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{
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struct simple_pm_bus *bus = dev_get_drvdata(dev);
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clk_bulk_disable_unprepare(bus->num_clks, bus->clks);
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return 0;
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}
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static int simple_pm_bus_runtime_resume(struct device *dev)
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{
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struct simple_pm_bus *bus = dev_get_drvdata(dev);
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int ret;
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ret = clk_bulk_prepare_enable(bus->num_clks, bus->clks);
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if (ret) {
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dev_err(dev, "failed to enable clocks: %d\n", ret);
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return ret;
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}
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return 0;
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}
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static const struct dev_pm_ops simple_pm_bus_pm_ops = {
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RUNTIME_PM_OPS(simple_pm_bus_runtime_suspend, simple_pm_bus_runtime_resume, NULL)
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NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
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};
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#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */
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static const struct of_device_id simple_pm_bus_of_match[] = {
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{ .compatible = "simple-pm-bus", },
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{ .compatible = "simple-bus", .data = ONLY_BUS },
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{ .compatible = "simple-mfd", .data = ONLY_BUS },
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{ .compatible = "isa", .data = ONLY_BUS },
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{ .compatible = "arm,amba-bus", .data = ONLY_BUS },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);
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static struct platform_driver simple_pm_bus_driver = {
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.probe = simple_pm_bus_probe,
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.remove = simple_pm_bus_remove,
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.driver = {
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.name = "simple-pm-bus",
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.of_match_table = simple_pm_bus_of_match,
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.pm = pm_ptr(&simple_pm_bus_pm_ops),
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},
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};
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module_platform_driver(simple_pm_bus_driver);
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MODULE_DESCRIPTION("Simple Power-Managed Bus Driver");
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MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
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MODULE_LICENSE("GPL v2");
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