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Message-ID: <CAOh2x=narPBYBNMMs5Qw_rGSgVsSNumb_jw_88C1PNGEc6sSEw@mail.gmail.com>
Date: Tue, 12 Mar 2013 18:49:38 +0800
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Amit Daniel Kachhap <amit.daniel@...sung.com>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
"Rafael J. Wysocki" <rjw@...k.pl>,
linux-samsung-soc@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
Kukjin Kim <kgene.kim@...sung.com>,
Thomas Abraham <thomas.abraham@...aro.org>,
cpufreq@...r.kernel.org,
Inderpal Singh <inderpal.singh@...aro.org>,
Sylwester Nawrocki <s.nawrocki@...sung.com>,
Russell King - ARM Linux <linux@....linux.org.uk>
Subject: Re: [PATCH V4 1/4] cpufreq: exynos: Adding cpufreq driver for exynos5440
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@...sung.com> 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@...sung.com>
> ---
> .../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@...000 {
> + 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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