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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 Kamil,

Looks good to me. But, I have some comment. Please check them.

After this patch, exynos_bus_target is perfectly same with
exynos_bus_passive_target. The exynos_bus_passive_target() could be removed.

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 ?

> 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.

> }
>
> + bus->opp_table = opp_table;

Add blank line.

> /*
> * 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).

> +err_reg:
> + if (bus->opp_table) {
> + dev_pm_opp_put_regulators(bus->opp_table);
> + bus->opp_table = NULL;
> + }
>
> return ret;
> }
>


--
Best Regards,
Chanwoo Choi
Samsung Electronics

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