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Date: Wed, 26 Jun 2019 00:37:07 +0200
From: Paul Cercueil <paul@...pouillou.net>
To: Stephen Boyd <sboyd@...nel.org>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>,
James Hogan <jhogan@...nel.org>,
Jason Cooper <jason@...edaemon.net>,
Jonathan Corbet <corbet@....net>,
Lee Jones <lee.jones@...aro.org>,
Marc Zyngier <marc.zyngier@....com>,
Michael Turquette <mturquette@...libre.com>,
Paul Burton <paul.burton@...s.com>,
Ralf Baechle <ralf@...ux-mips.org>,
Thomas Gleixner <tglx@...utronix.de>,
Mathieu Malaterre <malat@...ian.org>, od@...c.me,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mips@...r.kernel.org, linux-doc@...r.kernel.org,
linux-clk@...r.kernel.org, Artur Rojek <contact@...ur-rojek.eu>
Subject: Re: [PATCH v13 05/13] clk: ingenic: Add driver for the TCU clocks
Le mer. 26 juin 2019 à 0:09, Stephen Boyd <sboyd@...nel.org> a écrit :
> Quoting Paul Cercueil (2019-06-24 15:57:51)
>> diff --git a/drivers/clk/ingenic/tcu.c b/drivers/clk/ingenic/tcu.c
>> new file mode 100644
>> index 000000000000..6d667c4a2bd5
>> --- /dev/null
>> +++ b/drivers/clk/ingenic/tcu.c
>> @@ -0,0 +1,473 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * JZ47xx SoCs TCU clocks driver
>> + * Copyright (C) 2019 Paul Cercueil <paul@...pouillou.net>
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/clockchips.h>
>> +#include <linux/mfd/ingenic-tcu.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +#include <linux/syscore_ops.h>
>> +
>> +#include <dt-bindings/clock/ingenic,tcu.h>
>> +
> [...]
>> +
>> +static const struct ingenic_soc_info jz4740_soc_info = {
>> + .num_channels = 8,
>> + .has_ost = false,
>> + .has_tcu_clk = true,
>> +};
>> +
>> +static const struct ingenic_soc_info jz4725b_soc_info = {
>> + .num_channels = 6,
>> + .has_ost = true,
>> + .has_tcu_clk = true,
>> +};
>> +
>> +static const struct ingenic_soc_info jz4770_soc_info = {
>> + .num_channels = 8,
>> + .has_ost = true,
>> + .has_tcu_clk = false,
>> +};
>> +
>> +static const struct of_device_id ingenic_tcu_of_match[]
>> __initconst = {
>> + { .compatible = "ingenic,jz4740-tcu", .data =
>> &jz4740_soc_info, },
>> + { .compatible = "ingenic,jz4725b-tcu", .data =
>> &jz4725b_soc_info, },
>> + { .compatible = "ingenic,jz4770-tcu", .data =
>> &jz4770_soc_info, },
>> + { }
>> +};
>> +
>> +static int __init ingenic_tcu_probe(struct device_node *np)
>> +{
>> + const struct of_device_id *id =
>> of_match_node(ingenic_tcu_of_match, np);
>> + struct ingenic_tcu *tcu;
>> + struct regmap *map;
>> + unsigned int i;
>> + int ret;
>> +
>> + map = ingenic_tcu_get_regmap(np);
>> + if (IS_ERR(map))
>> + return PTR_ERR(map);
>> +
>> + tcu = kzalloc(sizeof(*tcu), GFP_KERNEL);
>> + if (!tcu)
>> + return -ENOMEM;
>> +
>> + tcu->map = map;
>> + tcu->soc_info = id->data;
>> +
>> + if (tcu->soc_info->has_tcu_clk) {
>> + tcu->clk = of_clk_get_by_name(np, "tcu");
>
> Do you need to get the clk by name? Or can that clk be "known" to the
> TCU somehow so we can already have a direct clk pointer?
This clock is provided by a separate driver, so I have to obtain the
clock pointer from devicetree.
>
>> + if (IS_ERR(tcu->clk)) {
>> + ret = PTR_ERR(tcu->clk);
>> + pr_crit("Cannot get TCU clock\n");
>> + goto err_free_tcu;
>> + }
>> +
>> + ret = clk_prepare_enable(tcu->clk);
>> + if (ret) {
>> + pr_crit("Unable to enable TCU clock\n");
>> + goto err_put_clk;
>> + }
>> + }
>> +
>> + tcu->clocks = kzalloc(sizeof(*tcu->clocks) +
>> + sizeof(*tcu->clocks->hws) *
>> TCU_CLK_COUNT,
>> + GFP_KERNEL);
>> + if (!tcu->clocks) {
>> + ret = -ENOMEM;
>> + goto err_clk_disable;
>> + }
>> +
>> + tcu->clocks->num = TCU_CLK_COUNT;
>> +
>> + for (i = 0; i < tcu->soc_info->num_channels; i++) {
>> + ret = ingenic_tcu_register_clock(tcu, i,
>> TCU_PARENT_EXT,
>> +
>> &ingenic_tcu_clk_info[i],
>> + tcu->clocks);
>> + if (ret) {
>> + pr_crit("cannot register clock %i\n", i);
>> + goto err_unregister_timer_clocks;
>> + }
>> + }
>> +
>> + /*
>> + * We set EXT as the default parent clock for all the TCU
>> clocks
>> + * except for the watchdog one, where we set the RTC clock
>> as the
>> + * parent. Since the EXT and PCLK are much faster than the
>> RTC clock,
>> + * the watchdog would kick after a maximum time of 5s, and
>> we might
>> + * want a slower kicking time.
>> + */
>> + ret = ingenic_tcu_register_clock(tcu, TCU_CLK_WDT,
>> TCU_PARENT_RTC,
>> +
>> &ingenic_tcu_watchdog_clk_info,
>> + tcu->clocks);
>> + if (ret) {
>> + pr_crit("cannot register watchdog clock\n");
>> + goto err_unregister_timer_clocks;
>> + }
>> +
>> + if (tcu->soc_info->has_ost) {
>> + ret = ingenic_tcu_register_clock(tcu, TCU_CLK_OST,
>> + TCU_PARENT_EXT,
>> +
>> &ingenic_tcu_ost_clk_info,
>> + tcu->clocks);
>> + if (ret) {
>> + pr_crit("cannot register ost clock\n");
>> + goto err_unregister_watchdog_clock;
>> + }
>> + }
>> +
>> + ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get,
>> tcu->clocks);
>> + if (ret) {
>> + pr_crit("cannot add OF clock provider\n");
>> + goto err_unregister_ost_clock;
>> + }
>> +
>> + ingenic_tcu = tcu;
>> +
>> + return 0;
>> +
>> +err_unregister_ost_clock:
>> + if (tcu->soc_info->has_ost)
>> + clk_hw_unregister(tcu->clocks->hws[i + 1]);
>> +err_unregister_watchdog_clock:
>> + clk_hw_unregister(tcu->clocks->hws[i]);
>> +err_unregister_timer_clocks:
>> + for (i = 0; i < tcu->clocks->num; i++)
>> + if (tcu->clocks->hws[i])
>> + clk_hw_unregister(tcu->clocks->hws[i]);
>> + kfree(tcu->clocks);
>> +err_clk_disable:
>> + if (tcu->soc_info->has_tcu_clk)
>> + clk_disable_unprepare(tcu->clk);
>> +err_put_clk:
>> + if (tcu->soc_info->has_tcu_clk)
>> + clk_put(tcu->clk);
>> +err_free_tcu:
>> + kfree(tcu);
>> + return ret;
>
> Too bad this isn't a device with devm!
>
>> +}
>> +
>> +static int __maybe_unused tcu_pm_suspend(void)
>> +{
>> + struct ingenic_tcu *tcu = ingenic_tcu;
>> +
>> + if (tcu->clk)
>> + clk_disable(tcu->clk);
>
> Do you need to unprepare? Or it just isn't possible because this is
> called from syscore and thus we can't sleep?
I thought that clk_disable() was enough. We don't actually need to
unprepare, do we? And yes, as you pointed out, this call cannot sleep.
>> +
>> + return 0;
>> +}
>> +
>> +static void __maybe_unused tcu_pm_resume(void)
>> +{
>> + struct ingenic_tcu *tcu = ingenic_tcu;
>> +
>> + if (tcu->clk)
>> + clk_enable(tcu->clk);
>> +}
>> +
>> +static struct syscore_ops __maybe_unused tcu_pm_ops = {
>> + .suspend = tcu_pm_suspend,
>> + .resume = tcu_pm_resume,
>> +};
>> +
>> +static void __init ingenic_tcu_init(struct device_node *np)
>> +{
>> + int ret = ingenic_tcu_probe(np);
>> +
>> + if (ret)
>> + pr_crit("Failed to initialize TCU clocks: %i\n",
>> ret);
>
> Should be %d instead of %i? Applies to all this file.
OK.
Thanks,
-Paul
>> +
>> + if (IS_ENABLED(CONFIG_PM_SLEEP))
>> + register_syscore_ops(&tcu_pm_ops);
>> +}
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