Re: [linux-pm] [PATCH] opp: introduce library for device-specificOPPs

From: Nishanth Menon
Date: Fri Sep 17 2010 - 11:54:04 EST


Mark Brown had written, on 09/17/2010 10:36 AM, the following:
On Thu, Sep 16, 2010 at 08:29:33PM -0500, Nishanth Menon wrote:

+struct opp_def {
+ unsigned long freq;
+ unsigned long u_volt;
+
+ bool enabled;
+};

It might be clearer to use some term other than enabled in the code -
when reading I wasn't immediately sure if enabled meant that it was
available to be selected or if it was the active operating point. How
about 'allowed' (though I'm not 100% happy with that)?
;).. The opp is enabled or disabled if it is populated, it is implicit as being available but not enabled- how about active? this would change the opp_enable/disable functions to opp_activate, opp_deactivate..

Recommendations folks?


+static inline int opp_add(struct device *dev, const struct opp_def *opp_def)
+{
+ return ERR_PTR(-EINVAL);
+}

Mismatch with the return type and value here.
/me kicks himself.. ouch.. thanks.. will fix in v2.


+/**
+ * opp_enable() - Enable a specific OPP
+ * @opp: Pointer to opp
+ *
+ * Enables a provided opp. If the operation is valid, this returns 0, else the
+ * corresponding error value.
+ *
+ * OPP used here is from the the opp_is_valid/opp_has_freq or other search
+ * functions
+ */
+int opp_enable(struct opp *opp)
+{
+ if (unlikely(!opp || IS_ERR(opp))) {
+ pr_err("%s: Invalid parameters being passed\n", __func__);
+ return -EINVAL;
+ }
+
+ if (!opp->enabled && opp->dev_opp)
+ opp->dev_opp->enabled_opp_count++;
+
+ opp->enabled = true;
+
+ return 0;
+}

When reading the description I'd expected to see some facility to
trigger selection of an active operating point in the library (possibly
as a separate call since you might have a bunch of operating points
being updated in quick succession) but it looks like that needs to be
supplied externally at the minute?
The intent is we use the opp_search* functions to pick up the opp and enable/activate it and disable/deactivate it.

--
Regards,
Nishanth Menon
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