![Pawel Moll](/assets/img/avatar_default.png)
Components of the Versatile Express platform (configuration microcontrollers on motherboard and daughterboards in particular) talk to each other over a custom configuration bus. They provide miscellaneous functions (from clock generator control to energy sensors) which are represented as platform devices (and Device Tree nodes). The transactions on the bus can be generated by different "bridges" in the system, some of which are universal for the whole platform (for the price of high transfer latencies), others restricted to a subsystem (but much faster). Until now drivers for such functions were using custom "func" API, which is being replaced in this patch by regmap calls. This required: * a rework (and move to drivers/bus directory, as suggested by Samuel and Arnd) of the config bus core, which is much simpler now and uses device model infrastructure (class) to keep track of the bridges; non-DT case (soon to be retired anyway) is simply covered by a special device registration function * the new config-bus driver also takes over device population, so there is no need for special matching table for of_platform_populate nor "simple-bus" hack in the arm64 model dtsi file (relevant bindings documentation has been updated); this allows all the vexpress devices fit into normal device model, making it possible to remove plenty of early inits and other hacks in the near future * adaptation of the syscfg bridge implementation in the sysreg driver, again making it much simpler; there is a special case of the "energy" function spanning two registers, where they should be both defined in the tree now, but backward compatibility is maintained in the code * modification of the relevant drivers: * hwmon - just a straight-forward API change * power/reset driver - API change * regulator - API change plus error handling simplification * osc clock driver - this one required larger rework in order to turn in into a standard platform driver Signed-off-by: Pawel Moll <pawel.moll@arm.com> Acked-by: Mark Brown <broonie@linaro.org> Acked-by: Lee Jones <lee.jones@linaro.org> Acked-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Mike Turquette <mturquette@linaro.org>
148 lines
3.7 KiB
C
148 lines
3.7 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Copyright (C) 2012 ARM Limited
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*/
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#include <linux/delay.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/stat.h>
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#include <linux/vexpress.h>
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#include <asm/system_misc.h>
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static void vexpress_reset_do(struct device *dev, const char *what)
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{
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int err = -ENOENT;
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struct regmap *reg = dev_get_drvdata(dev);
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if (reg) {
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err = regmap_write(reg, 0, 0);
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if (!err)
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mdelay(1000);
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}
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dev_emerg(dev, "Unable to %s (%d)\n", what, err);
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}
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static struct device *vexpress_power_off_device;
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static void vexpress_power_off(void)
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{
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vexpress_reset_do(vexpress_power_off_device, "power off");
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}
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static struct device *vexpress_restart_device;
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static void vexpress_restart(enum reboot_mode reboot_mode, const char *cmd)
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{
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vexpress_reset_do(vexpress_restart_device, "restart");
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}
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static ssize_t vexpress_reset_active_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return sprintf(buf, "%d\n", vexpress_restart_device == dev);
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}
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static ssize_t vexpress_reset_active_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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long value;
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int err = kstrtol(buf, 0, &value);
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if (!err && value)
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vexpress_restart_device = dev;
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return err ? err : count;
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}
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DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
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vexpress_reset_active_store);
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enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
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static struct of_device_id vexpress_reset_of_match[] = {
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{
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.compatible = "arm,vexpress-reset",
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.data = (void *)FUNC_RESET,
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}, {
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.compatible = "arm,vexpress-shutdown",
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.data = (void *)FUNC_SHUTDOWN
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}, {
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.compatible = "arm,vexpress-reboot",
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.data = (void *)FUNC_REBOOT
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},
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{}
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};
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static int vexpress_reset_probe(struct platform_device *pdev)
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{
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enum vexpress_reset_func func;
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const struct of_device_id *match =
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of_match_device(vexpress_reset_of_match, &pdev->dev);
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struct regmap *regmap;
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if (match)
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func = (enum vexpress_reset_func)match->data;
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else
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func = pdev->id_entry->driver_data;
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regmap = devm_regmap_init_vexpress_config(&pdev->dev);
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if (IS_ERR(regmap))
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return PTR_ERR(regmap);
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dev_set_drvdata(&pdev->dev, regmap);
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switch (func) {
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case FUNC_SHUTDOWN:
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vexpress_power_off_device = &pdev->dev;
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pm_power_off = vexpress_power_off;
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break;
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case FUNC_RESET:
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if (!vexpress_restart_device)
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vexpress_restart_device = &pdev->dev;
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arm_pm_restart = vexpress_restart;
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device_create_file(&pdev->dev, &dev_attr_active);
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break;
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case FUNC_REBOOT:
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vexpress_restart_device = &pdev->dev;
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arm_pm_restart = vexpress_restart;
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device_create_file(&pdev->dev, &dev_attr_active);
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break;
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};
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return 0;
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}
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static const struct platform_device_id vexpress_reset_id_table[] = {
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{ .name = "vexpress-reset", .driver_data = FUNC_RESET, },
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{ .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, },
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{ .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, },
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{}
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};
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static struct platform_driver vexpress_reset_driver = {
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.probe = vexpress_reset_probe,
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.driver = {
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.name = "vexpress-reset",
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.of_match_table = vexpress_reset_of_match,
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},
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.id_table = vexpress_reset_id_table,
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};
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static int __init vexpress_reset_init(void)
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{
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return platform_driver_register(&vexpress_reset_driver);
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}
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device_initcall(vexpress_reset_init);
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