[PATCH v2 2/2] hw_random: timeriomem_rng: Allow setting RNG quality from platform data

[Rick Altherr]

When a hw_random device's quality is non-zero, it will automatically be
used to fill the kernel's entropy pool.  Since timeriomem_rng is used by
many different devices, the quality needs to be provided by platform
data or device tree.

Signed-off-by: Rick Altherr <ralth...@google.com>
---

Changes in v2:
- Adjust header comment for platform data quality property to match code
and DT bindings

 drivers/char/hw_random/timeriomem-rng.c | 7 +++++++
 include/linux/timeriomem-rng.h          | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/drivers/char/hw_random/timeriomem-rng.c 
b/drivers/char/hw_random/timeriomem-rng.c
index a0faa5f05deb..03ff5483d865 100644
--- a/drivers/char/hw_random/timeriomem-rng.c
+++ b/drivers/char/hw_random/timeriomem-rng.c
@@ -151,8 +151,15 @@ static int timeriomem_rng_probe(struct platform_device 
*pdev)
                        dev_err(&pdev->dev, "missing period\n");
                        return -EINVAL;
                }
+
+               if (!of_property_read_u32(pdev->dev.of_node,
+                                               "quality", &i))
+                       priv->rng_ops.quality = i;
+               else
+                       priv->rng_ops.quality = 0;
        } else {
                period = pdata->period;
+               priv->rng_ops.quality = pdata->quality;
        }
 
        priv->period = ns_to_ktime(period * NSEC_PER_USEC);
diff --git a/include/linux/timeriomem-rng.h b/include/linux/timeriomem-rng.h
index 46eb27ddbfab..3e00122bcf88 100644
--- a/include/linux/timeriomem-rng.h
+++ b/include/linux/timeriomem-rng.h
@@ -13,4 +13,7 @@ struct timeriomem_rng_data {
 
        /* measures in usecs */
        unsigned int            period;
+
+       /* bits of entropy per 1024 bits read */
+       unsigned int            quality;
 };
-- 
2.13.0.303.g4ebf302169-goog