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Date: Thu, 25 Jul 2019 17:15:47 +0200
From: Kamil Konieczny <k.konieczny@...tner.samsung.com>
To: cwchoi00@...il.com
Cc: Chanwoo Choi <cw00.choi@...sung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Krzysztof Kozlowski <krzk@...nel.org>,
Kukjin Kim <kgene@...nel.org>,
Kyungmin Park <kyungmin.park@...sung.com>,
Mark Rutland <mark.rutland@....com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Nishanth Menon <nm@...com>, Rob Herring <robh+dt@...nel.org>,
Stephen Boyd <sboyd@...nel.org>,
Viresh Kumar <vireshk@...nel.org>,
devicetree <devicetree@...r.kernel.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Linux PM list <linux-pm@...r.kernel.org>,
linux-samsung-soc <linux-samsung-soc@...r.kernel.org>
Subject: Re: [PATCH v3 3/5] devfreq: exynos-bus: convert to use
dev_pm_opp_set_rate()
Hi,
On 25.07.2019 16:53, Chanwoo Choi wrote:
> 2019년 7월 25일 (목) 오후 11:19, Kamil Konieczny
> <k.konieczny@...tner.samsung.com>님이 작성:
>>
>> Hi Chanwoo,
>>
>> On 25.07.2019 12:17, Chanwoo Choi wrote:
>>> Hi Kamil,
>>>
>>> Looks good to me. But, I have some comment. Please check them.
>>
>> Thank you for review, please see answers below.
>>
>>> After this patch, exynos_bus_target is perfectly same with
>>> exynos_bus_passive_target. The exynos_bus_passive_target() could be removed.
>>
>> Ok, I will make it in separate patch to simplify review process.
>
> I think you can just modify this patch without any separate patch.
Do you want me to send v5 with patch 5 squashed in patch 3 ?
>>> On 19. 7. 20. 오전 12:05, k.konieczny@...tner.samsung.com wrote:
>>>> Reuse opp core code for setting bus clock and voltage. As a side
>>>> effect this allow useage of coupled regulators feature (required
>>>
>>> s/useage/usage ?
>>
>> Good catch, I will change it.
>>
>>>> for boards using Exynos5422/5800 SoCs) because dev_pm_opp_set_rate()
>>>> uses regulator_set_voltage_triplet() for setting regulator voltage
>>>> while the old code used regulator_set_voltage_tol() with fixed
>>>> tolerance. This patch also removes no longer needed parsing of DT
>>>> property "exynos,voltage-tolerance" (no Exynos devfreq DT node uses
>>>> it).
>>>>
>>>> Signed-off-by: Kamil Konieczny <k.konieczny@...tner.samsung.com>
>>>> ---
>>>> drivers/devfreq/exynos-bus.c | 143 +++++++++--------------------------
>>>> 1 file changed, 37 insertions(+), 106 deletions(-)
>>>>
>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>> index f391044aa39d..c2147b0912a0 100644
>>>> --- a/drivers/devfreq/exynos-bus.c
>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>> @@ -25,7 +25,6 @@
>>>> #include <linux/slab.h>
>>>>
>>>> #define DEFAULT_SATURATION_RATIO 40
>>>> -#define DEFAULT_VOLTAGE_TOLERANCE 2
>>>>
>>>> struct exynos_bus {
>>>> struct device *dev;
>>>> @@ -37,9 +36,9 @@ struct exynos_bus {
>>>>
>>>> unsigned long curr_freq;
>>>>
>>>> - struct regulator *regulator;
>>>> + struct opp_table *opp_table;
>>>> +
>>>> struct clk *clk;
>>>> - unsigned int voltage_tolerance;
>>>> unsigned int ratio;
>>>> };
>>>>
>>>> @@ -99,56 +98,23 @@ static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
>>>> {
>>>> struct exynos_bus *bus = dev_get_drvdata(dev);
>>>> struct dev_pm_opp *new_opp;
>>>> - unsigned long old_freq, new_freq, new_volt, tol;
>>>> int ret = 0;
>>>>
>>>> - /* Get new opp-bus instance according to new bus clock */
>>>> + /* Get correct frequency for bus. */
>>>> new_opp = devfreq_recommended_opp(dev, freq, flags);
>>>> if (IS_ERR(new_opp)) {
>>>> dev_err(dev, "failed to get recommended opp instance\n");
>>>> return PTR_ERR(new_opp);
>>>> }
>>>>
>>>> - new_freq = dev_pm_opp_get_freq(new_opp);
>>>> - new_volt = dev_pm_opp_get_voltage(new_opp);
>>>> dev_pm_opp_put(new_opp);
>>>>
>>>> - old_freq = bus->curr_freq;
>>>> -
>>>> - if (old_freq == new_freq)
>>>> - return 0;
>>>> - tol = new_volt * bus->voltage_tolerance / 100;
>>>> -
>>>> /* Change voltage and frequency according to new OPP level */
>>>> mutex_lock(&bus->lock);
>>>> + ret = dev_pm_opp_set_rate(dev, *freq);
>>>> + if (!ret)
>>>> + bus->curr_freq = *freq;
>>>>
>>>> - if (old_freq < new_freq) {
>>>> - ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
>>>> - if (ret < 0) {
>>>> - dev_err(bus->dev, "failed to set voltage\n");
>>>> - goto out;
>>>> - }
>>>> - }
>>>> -
>>>> - ret = clk_set_rate(bus->clk, new_freq);
>>>> - if (ret < 0) {
>>>> - dev_err(dev, "failed to change clock of bus\n");
>>>> - clk_set_rate(bus->clk, old_freq);
>>>> - goto out;
>>>> - }
>>>> -
>>>> - if (old_freq > new_freq) {
>>>> - ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
>>>> - if (ret < 0) {
>>>> - dev_err(bus->dev, "failed to set voltage\n");
>>>> - goto out;
>>>> - }
>>>> - }
>>>> - bus->curr_freq = new_freq;
>>>> -
>>>> - dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
>>>> - old_freq, new_freq, clk_get_rate(bus->clk));
>>>> -out:
>>>> mutex_unlock(&bus->lock);
>>>>
>>>> return ret;
>>>> @@ -195,8 +161,8 @@ static void exynos_bus_exit(struct device *dev)
>>>> dev_warn(dev, "failed to disable the devfreq-event devices\n");
>>>>
>>>> clk_disable_unprepare(bus->clk);
>>>> - if (bus->regulator)
>>>> - regulator_disable(bus->regulator);
>>>> + if (bus->opp_table)
>>>> + dev_pm_opp_put_regulators(bus->opp_table);
>>>>
>>>> dev_pm_opp_of_remove_table(dev);
>>>> }
>>>> @@ -209,39 +175,23 @@ static int exynos_bus_passive_target(struct device *dev, unsigned long *freq,
>>>> {
>>>> struct exynos_bus *bus = dev_get_drvdata(dev);
>>>> struct dev_pm_opp *new_opp;
>>>> - unsigned long old_freq, new_freq;
>>>> - int ret = 0;
>>>> + int ret;
>>>>
>>>> - /* Get new opp-bus instance according to new bus clock */
>>>> + /* Get correct frequency for bus. */
>>>> new_opp = devfreq_recommended_opp(dev, freq, flags);
>>>> if (IS_ERR(new_opp)) {
>>>> dev_err(dev, "failed to get recommended opp instance\n");
>>>> return PTR_ERR(new_opp);
>>>> }
>>>>
>>>> - new_freq = dev_pm_opp_get_freq(new_opp);
>>>> dev_pm_opp_put(new_opp);
>>>>
>>>> - old_freq = bus->curr_freq;
>>>> -
>>>> - if (old_freq == new_freq)
>>>> - return 0;
>>>> -
>>>> /* Change the frequency according to new OPP level */
>>>> mutex_lock(&bus->lock);
>>>> + ret = dev_pm_opp_set_rate(dev, *freq);
>>>> + if (!ret)
>>>> + bus->curr_freq = *freq;
>>>>
>>>> - ret = clk_set_rate(bus->clk, new_freq);
>>>> - if (ret < 0) {
>>>> - dev_err(dev, "failed to set the clock of bus\n");
>>>> - goto out;
>>>> - }
>>>> -
>>>> - *freq = new_freq;
>>>> - bus->curr_freq = new_freq;
>>>> -
>>>> - dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
>>>> - old_freq, new_freq, clk_get_rate(bus->clk));
>>>> -out:
>>>> mutex_unlock(&bus->lock);
>>>>
>>>> return ret;
>>>> @@ -259,20 +209,9 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
>>>> struct exynos_bus *bus)
>>>> {
>>>> struct device *dev = bus->dev;
>>>> - int i, ret, count, size;
>>>> -
>>>> - /* Get the regulator to provide each bus with the power */
>>>> - bus->regulator = devm_regulator_get(dev, "vdd");
>>>> - if (IS_ERR(bus->regulator)) {
>>>> - dev_err(dev, "failed to get VDD regulator\n");
>>>> - return PTR_ERR(bus->regulator);
>>>> - }
>>>> -
>>>> - ret = regulator_enable(bus->regulator);
>>>> - if (ret < 0) {
>>>> - dev_err(dev, "failed to enable VDD regulator\n");
>>>> - return ret;
>>>> - }
>>>> + struct opp_table *opp_table;
>>>> + const char *vdd = "vdd";
>>>> + int i, count, size;
>>>>
>>>> /*
>>>> * Get the devfreq-event devices to get the current utilization of
>>>> @@ -281,26 +220,29 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
>>>> count = devfreq_event_get_edev_count(dev);
>>>> if (count < 0) {
>>>> dev_err(dev, "failed to get the count of devfreq-event dev\n");
>>>> - ret = count;
>>>> - goto err_regulator;
>>>> + return count;
>>>> }
>>>> - bus->edev_count = count;
>>>>
>>>> + bus->edev_count = count;
>>>> size = sizeof(*bus->edev) * count;
>>>> bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
>>>> - if (!bus->edev) {
>>>> - ret = -ENOMEM;
>>>> - goto err_regulator;
>>>> - }
>>>> + if (!bus->edev)
>>>> + return -ENOMEM;
>>>>
>>>> for (i = 0; i < count; i++) {
>>>> bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
>>>> - if (IS_ERR(bus->edev[i])) {
>>>> - ret = -EPROBE_DEFER;
>>>> - goto err_regulator;
>>>> - }
>>>> + if (IS_ERR(bus->edev[i]))
>>>> + return -EPROBE_DEFER;
>>>> + }
>>>> +
>>>> + opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
>>>> + if (IS_ERR(opp_table)) {
>>>> + i = PTR_ERR(opp_table);
>>>> + dev_err(dev, "failed to set regulators %d\n", i);
>>>> + return i;
>>>
>>> Maybe, you just used the 'i' defined variable instead of adding
>>> new variable. But, I think that you better to add new variable
>>> like 'err' for the readability. Or, jut use the 'PTR_ERR(opp_table)'
>>> directly without any additional variable.
>>
>> I will remove not related changes, so here I will reuse 'ret' variable.
>>
>>>> }
>>>>
>>>> + bus->opp_table = opp_table;
>>>
>>> Add blank line.
>>
>> OK
>>
>>>> /*
>>>> * Optionally, Get the saturation ratio according to Exynos SoC
>>>> * When measuring the utilization of each AXI bus with devfreq-event
>>>> @@ -314,16 +256,7 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
>>>> if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
>>>> bus->ratio = DEFAULT_SATURATION_RATIO;
>>>>
>>>> - if (of_property_read_u32(np, "exynos,voltage-tolerance",
>>>> - &bus->voltage_tolerance))
>>>> - bus->voltage_tolerance = DEFAULT_VOLTAGE_TOLERANCE;
>>>> -
>>>> return 0;
>>>> -
>>>> -err_regulator:
>>>> - regulator_disable(bus->regulator);
>>>> -
>>>> - return ret;
>>>> }
>>>>
>>>> static int exynos_bus_parse_of(struct exynos_bus *bus)
>>>> @@ -414,12 +347,8 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>
>>>> /* Parse the device-tree to get the resource information */
>>>> ret = exynos_bus_parse_of(bus);
>>>> - if (ret < 0) {
>>>> - if (!passive)
>>>> - regulator_disable(bus->regulator);
>>>> -
>>>> - return ret;
>>>> - }
>>>> + if (ret < 0)
>>>> + goto err_reg;
>>>>
>>>> if (passive)
>>>> goto passive;
>>>> @@ -512,10 +441,12 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>
>>>> err:
>>>> clk_disable_unprepare(bus->clk);
>>>> - if (!passive)
>>>> - regulator_disable(bus->regulator);
>>>> -
>>>> dev_pm_opp_of_remove_table(dev);
>>>
>>> This function removes the 'opp_table'. But, the below code
>>> uses the 'opp_table' variable by dev_pm_opp_put_regulators().
>>>
>>> To disable the regulator, you have to call dev_pm_opp_of_remove_table(dev)
>>> after dev_pm_opp_put_regulators(bus->opp_table).
>>
>> Regulators should be set before dev_pm_opp_add_table(), so exit sequence
>> should be in reverse order,
>>
>> init order:
>>
>> exynos_bus_parent_parse_of()
>> dev_pm_opp_set_regulators()
>> exynos_bus_parse_of()
>> clk_prepare_enable()
>> dev_pm_opp_of_add_table()
>>
>> exit or error order:
>>
>> dev_pm_opp_of_remove_table()
>> clk_disable_unprepare()
>> if (bus->opp_table)
>> dev_pm_opp_put_regulators(bus->opp_table);
>
> dev_pm_opp_of_remove_table() have to be called at the end of exit sequence
> after disabling clock and put regulators. Because dev_pm_opp_of_remove_table()
> frees the 'opp_table' pointer of device.
>
> clk_disable_unprepare()
> if (bus->opp_table)
> dev_pm_opp_put_regulators(bus->opp_table);
> dev_pm_opp_of_remove_table()
The table is reference counted so it will be freed after count go to zero.
>> I will send v4 soon.
>>
>>>> +err_reg:
>>>> + if (bus->opp_table) {
>>>> + dev_pm_opp_put_regulators(bus->opp_table);
>>>> + bus->opp_table = NULL;
>>>> + }
>>>>
>>>> return ret;
>>>> }
--
Best regards,
Kamil Konieczny
Samsung R&D Institute Poland
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