Re: [PATCH 7/9] memory: samsung: exynos5422-dmc: Replace deprecated 'devfreq-events' property

Lukasz Luba
2019-12-17T11:04:09Z

Hi Chanwoo,

On 12/17/19 5:57 AM, Chanwoo Choi wrote:
> In order to remove the deprecated 'devfreq-events' property, replace with
> new 'exynos,ppmu-device' property in order to get the devfreq-event device
> in devicetree file instead of 'devfreq-events' property. But, to guarantee
> the backward-compatibility, keep the support 'devfreq-events' property.
>
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> .../memory-controllers/exynos5422-dmc.txt | 6 ++--
> drivers/memory/samsung/exynos5422-dmc.c | 29 +++++++++++++++----
> 2 files changed, 26 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt b/Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt
> index 02e4a1f862f1..1e1b3702f045 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt
> +++ b/Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt
> @@ -17,14 +17,14 @@ Required properties for DMC device for Exynos5422:
> - clock-names : should include "fout_spll", "mout_sclk_spll", "ff_dout_spll2",
> "fout_bpll", "mout_bpll", "sclk_bpll", "mout_mx_mspll_ccore",
> "mout_mclk_cdrex" entries
> -- devfreq-events : phandles for PPMU devices connected to this DMC.
> +- exynos,ppmu-device : phandles for PPMU devices connected to this DMC.
> - vdd-supply : phandle for voltage regulator which is connected.
> - reg : registers of two CDREX controllers.
> - operating-points-v2 : phandle for OPPs described in v2 definition.
> - device-handle : phandle of the connected DRAM memory device. For more
> information please refer to documentation file:
> Documentation/devicetree/bindings/ddr/lpddr3.txt
> -- devfreq-events : phandles of the PPMU events used by the controller.
> +- exynos,ppmu-device : phandles of the PPMU events used by the controller.
> - samsung,syscon-clk : phandle of the clock register set used by the controller,
> these registers are used for enabling a 'pause' feature and are not
> exposed by clock framework but they must be used in a safe way.
> @@ -73,7 +73,7 @@ Example:
> "mout_mx_mspll_ccore",
> "mout_mclk_cdrex";
> operating-points-v2 = <&dmc_opp_table>;
> - devfreq-events = <&ppmu_event3_dmc0_0>, <&ppmu_event3_dmc0_1>,
> + exynos,ppmu-device = <&ppmu_event3_dmc0_0>, <&ppmu_event3_dmc0_1>,
> <&ppmu_event3_dmc1_0>, <&ppmu_event3_dmc1_1>;
> device-handle = <&samsung_K3QF2F20DB>;
> vdd-supply = <&buck1_reg>;
> diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c
> index c3195111d646..96593f37a478 100644
> --- a/drivers/memory/samsung/exynos5422-dmc.c
> +++ b/drivers/memory/samsung/exynos5422-dmc.c
> @@ -1270,10 +1270,17 @@ static int exynos5_dmc_init_clks(struct exynos5_dmc *dmc)
> static struct devfreq_event_dev *get_edev_by_node(struct device_node *np,
> int index)
> {
> - struct device_node *node = of_parse_phandle(np, "devfreq-events",
> + struct device_node *node = of_parse_phandle(np, "exynos,ppmu-device",
> index);
> - if (!node)
> - return ERR_PTR(-ENODEV);
> + if (!node) {
> + /*
> + * Check the deprecated 'devfreq-events' property
> + * to support backward-compatibility.
> + */
> + node = of_parse_phandle(np, "devfreq-events", index);
> + if (!node)
> + return ERR_PTR(-ENODEV);
> + }
> return devfreq_event_get_edev_by_node(node);
> }
>
> @@ -1292,10 +1299,20 @@ static int exynos5_performance_counters_init(struct exynos5_dmc *dmc)
> int ret, i;
>
> dmc->num_counters = of_property_count_elems_of_size(dmc->dev->of_node,
> - "devfreq-events", sizeof(u32));
> + "exynos,ppmu-device", sizeof(u32));
> if (dmc->num_counters < 0) {
> - dev_err(dmc->dev, "could not get devfreq-event counters\n");
> - return dmc->num_counters;
> + /*
> + * Check the deprecated 'devfreq-events' property
> + * to support backward-compatibility.
> + */
> + dmc->num_counters = of_property_count_elems_of_size(
> + dmc->dev->of_node,
> + "devfreq-events", sizeof(u32));
> + if (dmc->num_counters < 0) {
> + dev_err(dmc->dev,
> + "could not get devfreq-event counters\n");
> + return dmc->num_counters;
> + }
> }
>
> counters_size = sizeof(struct devfreq_event_dev) * dmc->num_counters;
>

Looks good to me. The fallback with backward-compatibility is a good
idea in my opinion. Thank you for the change and feel free to and my:

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>

Regarding the whole patch set, for the first glance it looks reasonable
and good. AIRC some developers were arguing for the "devfreq-events"
entry in DT. Now it should be fine. I will spend more time today for
reviewing the whole patch set.

Regards,
Lukasz