Re: [PATCH v7 7/7] cpufreq: dt: Add support for interconnect bandwidth scaling

[Sibi Sankar]

Hey Georgi,

On 2020-04-24 21:24, Georgi Djakov wrote:

In addition to clocks and regulators, some devices can scale the bandwidth of their on-chip interconnect - for example between CPU and DDR memory. Add support for that, so that platforms which support it can make use of it.

Signed-off-by: Georgi Djakov <georgi.dja...@linaro.org>
---
v7:
* Drop using dev_pm_opp_set_paths(), as it has been removed.
* Add Kconfig dependency on INTERCONNECT, as it can be module.

v2: https://lore.kernel.org/r/20190423132823.7915-6-georgi.dja...@linaro.org

 drivers/cpufreq/Kconfig      |  1 +
 drivers/cpufreq/cpufreq-dt.c | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index c3e6bd59e920..db2ad54ee67f 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -217,6 +217,7 @@ config CPUFREQ_DT

 config CPUFREQ_DT_PLATDEV
        bool
+       depends on INTERCONNECT || !INTERCONNECT
        help
          This adds a generic DT based cpufreq platdev driver for frequency
          management.  This creates a 'cpufreq-dt' platform device, on the

diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c

index 26fe8dfb9ce6..4ecef3257532 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -13,6 +13,7 @@
 #include <linux/cpufreq.h>
 #include <linux/cpumask.h>
 #include <linux/err.h>
+#include <linux/interconnect.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/pm_opp.h>
@@ -95,6 +96,7 @@ static int resources_available(void)
        struct device *cpu_dev;
        struct regulator *cpu_reg;
        struct clk *cpu_clk;
+       struct icc_path *cpu_path;
        int ret = 0;
        const char *name;

@@ -121,6 +123,19 @@ static int resources_available(void)

        clk_put(cpu_clk);

+       cpu_path = of_icc_get(cpu_dev, NULL);
+       ret = PTR_ERR_OR_ZERO(cpu_path);

Wouldn't we want to verify all
available paths instead of just
the first path?

+       if (ret) {
+               if (ret == -EPROBE_DEFER)
+                       dev_dbg(cpu_dev, "defer icc path: %d\n", ret);
+               else
+                       dev_err(cpu_dev, "failed to get icc path: %d\n", ret);
+
+               return ret;
+       }
+
+       icc_put(cpu_path);
+
        name = find_supply_name(cpu_dev);
        /* Platform doesn't require regulator */
        if (!name)

--
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