Re: [PATCH V4 1/4] cpufreq: exynos: Adding cpufreq driver for exynos5440

[Viresh Kumar]

This is what Russell told me a long time back:
"Don't use Adding, Fixing, etc words as this work is not something, which is
already done."

So your subject should have been: "cpufreq: exynos: Add cpufreq driver
for exynos5440"

Fix it if you need another version, which i believe you do :)

On Tue, Mar 12, 2013 at 5:58 PM, Amit Daniel Kachhap
<amit.daniel@xxxxxxxxxxx> wrote:
> This patch adds dvfs support for exynos5440 SOC. This soc has 4 cores and
> they scale at same frequency. The nature of exynos5440 clock controller is
> different from previous exynos controllers so not using the common exynos
> cpufreq framework. The major difference being interrupt notfication for

s/notfication/notification

> frequency change. Also, OPP library is used for device tree parsing to get
> different parameters like frequency, voltage etc. Since the opp library sorts
> the frequency table in ascending order so they are again re-arranged in
> descending order. This will have one-to-one mapping with the clock controller
> state management logic.
>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
> ---
>  .../bindings/cpufreq/cpufreq-exynos5440.txt        |   29 ++
>  drivers/cpufreq/Kconfig.arm                        |    9 +
>  drivers/cpufreq/Makefile                           |    1 +
>  drivers/cpufreq/exynos5440-cpufreq.c               |  466 ++++++++++++++++++++
>  4 files changed, 505 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>  create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c
>
> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> new file mode 100644
> index 0000000..a0dbe0b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> @@ -0,0 +1,29 @@
> +
> +Exynos5440 cpufreq driver
> +-------------------
> +
> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
> +
> +Required properties:
> +- interrupts: Interrupt to know the completion of cpu frequency change.
> +- operating-points: Table of frequencies and voltage CPU could be transitioned into,
> +       in the decreasing order. Frequency should be in KHZ units and voltage

s/KHZ/KHz

> +       should be in microvolts.

probably s/microvolts/micro-volts ??

> +
> +Optional properties:
> +- clock-latency: Clock monitor latency in microsecond.
> +
> +All the required listed above must be defined under node cpufreq.
> +
> +Example:
> +--------
> +       cpufreq@160000 {
> +               compatible = "samsung,exynos5440-cpufreq";
> +               reg = <0x160000 0x1000>;
> +               interrupts = <0 57 0>;
> +               operating-points = <
> +                               1000000 975000
> +                               800000  925000>;
> +               clock-latency = <100000>;
> +       };
> +

> diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
> +static void exynos_enable_dvfs(void)
> +{

> +       /* Set initial performance index */
> +       for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
> +               if (freq_table[i].frequency == dvfs_info->cur_frequency)
> +                       break;
> +
> +       if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
> +               dev_crit(dvfs_info->dev, "Boot up frequency not supported\n");
> +               /* Assign the highest frequency */
> +               i = 0;
> +               dvfs_info->cur_frequency = freq_table[i].frequency;

What about:

dvfs_info->cur_frequency = freq_table[0].frequency;

as i don't see i being used again?

> +       }

> +}

> +static int exynos_target(struct cpufreq_policy *policy,
> +                         unsigned int target_freq,
> +                         unsigned int relation)
> +{

> +       if (cpufreq_frequency_table_target(policy, freq_table,
> +                                          target_freq, relation, &index)) {
> +               ret = -EINVAL;

Use the error value returned by called functions, probably i gave this
comment last time too?

> +               goto out;
> +       }

> +}

> +static void exynos_sort_descend_freq_table(void)
> +{
> +       struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
> +       int i = 0, index;
> +       unsigned int tmp_freq;
> +
> +       /*
> +        * Freq table is already in ascending order as it is created from
> +        * OPP library, so just swap the elements to make it descending.

why??

> +        */
> +       for (i = 0; i < dvfs_info->freq_count / 2; i++) {
> +               index = dvfs_info->freq_count - i - 1;
> +               tmp_freq = freq_tbl[i].frequency;
> +               freq_tbl[i].frequency = freq_tbl[index].frequency;
> +               freq_tbl[index].frequency = tmp_freq;
> +       }
> +}
> +

> +static int exynos_cpufreq_probe(struct platform_device *pdev)
> +{
> +       int ret = -EINVAL;
> +       struct device_node *np;
> +       struct resource res;
> +
> +       np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
> +       if (!np)
> +               return -ENODEV;
> +
> +       dvfs_info = devm_kzalloc(&pdev->dev, sizeof(*dvfs_info), GFP_KERNEL);
> +       if (!dvfs_info) {
> +               ret = -ENOMEM;
> +               goto err_put_node;
> +       }
> +
> +       dvfs_info->dev = &pdev->dev;
> +       dvfs_info->dev->of_node = np;
> +
> +       ret = of_address_to_resource(np, 0, &res);
> +       if (ret)
> +               goto err_put_node;
> +
> +       dvfs_info->base = devm_ioremap_resource(dvfs_info->dev, &res);
> +       if (IS_ERR(dvfs_info->base)) {
> +               ret = PTR_ERR(dvfs_info->base);
> +               goto err_put_node;
> +       }
> +
> +       dvfs_info->irq = irq_of_parse_and_map(np, 0);
> +       if (dvfs_info->irq == 0) {

maybe, if (!dvfs_info->irq) {


> +               dev_err(dvfs_info->dev, "No cpufreq irq found\n");
> +               ret = -ENODEV;
> +               goto err_put_node;
> +       }
> +
> +       ret = of_init_opp_table(dvfs_info->dev);
> +       if (ret) {
> +               dev_err(dvfs_info->dev, "failed to init OPP table: %d\n", ret);
> +               goto err_put_node;
> +       }
> +
> +       ret = opp_init_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
> +       if (ret) {
> +               dev_err(dvfs_info->dev,
> +                       "failed to init cpufreq table: %d\n", ret);
> +               goto err_put_node;
> +       }
> +       dvfs_info->freq_count = opp_get_opp_count(dvfs_info->dev);
> +       exynos_sort_descend_freq_table();
> +
> +       if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
> +               dvfs_info->latency = DEF_TRANS_LATENCY;
> +
> +       dvfs_info->cpu_clk = devm_clk_get(dvfs_info->dev, "armclk");
> +       if (IS_ERR(dvfs_info->cpu_clk)) {
> +               dev_err(dvfs_info->dev, "Failed to get cpu clock\n");
> +               ret = PTR_ERR(dvfs_info->cpu_clk);
> +               goto err_free_table;
> +       }
> +
> +       dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
> +       if (!dvfs_info->cur_frequency) {
> +               dev_err(dvfs_info->dev, "Failed to get clock rate\n");
> +               ret = -EINVAL;
> +               goto err_free_table;
> +       }
> +       dvfs_info->cur_frequency /= 1000;
> +
> +       INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
> +       ret = devm_request_irq(dvfs_info->dev, dvfs_info->irq,
> +                               exynos_cpufreq_irq, IRQF_TRIGGER_NONE,
> +                               CPUFREQ_NAME, dvfs_info);
> +       if (ret) {
> +               dev_err(dvfs_info->dev, "Failed to register IRQ\n");
> +               goto err_free_table;
> +       }
> +
> +       ret = init_div_table();
> +       if (ret) {
> +               dev_err(dvfs_info->dev, "Failed to initialise div table\n");
> +               goto err_free_table;
> +       }
> +
> +       exynos_enable_dvfs();
> +       ret = cpufreq_register_driver(&exynos_driver);
> +       if (ret) {
> +               dev_err(dvfs_info->dev,
> +                       "%s: failed to register cpufreq driver\n", __func__);
> +               goto err_free_table;
> +       }
> +
> +       of_node_put(np);
> +       dvfs_info->dvfs_enabled = true;
> +       return 0;
> +
> +err_free_table:
> +       opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
> +err_put_node:
> +       of_node_put(np);
> +       dev_err(dvfs_info->dev, "%s: failed initialization\n", __func__);
> +       return ret;
> +}
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