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SubjectRe: [PATCH v3 3/5] devfreq: exynos-bus: convert to use dev_pm_opp_set_rate()
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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.

> On 19. 7. 20. 오전 12:05, k.konieczny@partner.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@partner.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);

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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