3b9334ac83
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>
138 lines
3.2 KiB
C
138 lines
3.2 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/clkdev.h>
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#include <linux/clk-provider.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/vexpress.h>
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struct vexpress_osc {
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struct regmap *reg;
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struct clk_hw hw;
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unsigned long rate_min;
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unsigned long rate_max;
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};
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#define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
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static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct vexpress_osc *osc = to_vexpress_osc(hw);
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u32 rate;
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regmap_read(osc->reg, 0, &rate);
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return rate;
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}
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static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *parent_rate)
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{
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struct vexpress_osc *osc = to_vexpress_osc(hw);
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if (WARN_ON(osc->rate_min && rate < osc->rate_min))
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rate = osc->rate_min;
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if (WARN_ON(osc->rate_max && rate > osc->rate_max))
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rate = osc->rate_max;
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return rate;
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}
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static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long parent_rate)
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{
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struct vexpress_osc *osc = to_vexpress_osc(hw);
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return regmap_write(osc->reg, 0, rate);
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}
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static struct clk_ops vexpress_osc_ops = {
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.recalc_rate = vexpress_osc_recalc_rate,
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.round_rate = vexpress_osc_round_rate,
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.set_rate = vexpress_osc_set_rate,
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};
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static int vexpress_osc_probe(struct platform_device *pdev)
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{
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struct clk_lookup *cl = pdev->dev.platform_data; /* Non-DT lookup */
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struct clk_init_data init;
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struct vexpress_osc *osc;
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struct clk *clk;
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u32 range[2];
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osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
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if (!osc)
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return -ENOMEM;
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osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
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if (IS_ERR(osc->reg))
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return PTR_ERR(osc->reg);
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if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
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ARRAY_SIZE(range)) == 0) {
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osc->rate_min = range[0];
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osc->rate_max = range[1];
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}
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if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
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&init.name) != 0)
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init.name = dev_name(&pdev->dev);
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init.ops = &vexpress_osc_ops;
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init.flags = CLK_IS_ROOT;
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init.num_parents = 0;
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osc->hw.init = &init;
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clk = clk_register(NULL, &osc->hw);
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if (IS_ERR(clk))
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return PTR_ERR(clk);
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of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
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/* Only happens for non-DT cases */
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if (cl) {
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cl->clk = clk;
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clkdev_add(cl);
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}
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dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
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return 0;
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}
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static struct of_device_id vexpress_osc_of_match[] = {
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{ .compatible = "arm,vexpress-osc", },
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{}
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};
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static struct platform_driver vexpress_osc_driver = {
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.driver = {
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.name = "vexpress-osc",
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.of_match_table = vexpress_osc_of_match,
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},
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.probe = vexpress_osc_probe,
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};
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static int __init vexpress_osc_init(void)
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{
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return platform_driver_register(&vexpress_osc_driver);
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}
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core_initcall(vexpress_osc_init);
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