[PATCH v2 07/12] hwrng: bcm2835-rng: Manage an optional clock
From: f.fainelli@gmail.com (Florian Fainelli)
Date: 2017-11-08 00:47:45
Also in:
linux-crypto, linux-devicetree, lkml
Subsystem:
hardware random number generator core, the rest · Maintainers:
Olivia Mackall, Herbert Xu, Linus Torvalds
One of the last steps before bcm63xx-rng can be eliminated is to manage a clock during hwrng::init and hwrng::cleanup, so fetch it in the probe function, and manage it during these two steps when valid. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> --- drivers/char/hw_random/bcm2835-rng.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
index ed20e0b6b7ae..99b56fd5482c 100644
--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c@@ -15,6 +15,7 @@ #include <linux/of_platform.h> #include <linux/platform_device.h> #include <linux/printk.h> +#include <linux/clk.h> #define RNG_CTRL 0x0 #define RNG_STATUS 0x4
@@ -33,6 +34,7 @@ struct bcm2835_rng_priv { struct hwrng rng; void __iomem *base; bool mask_interrupts; + struct clk *clk; }; static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng)
@@ -66,8 +68,15 @@ static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max, static int bcm2835_rng_init(struct hwrng *rng) { struct bcm2835_rng_priv *priv = to_rng_priv(rng); + int ret = 0; u32 val; + if (!IS_ERR(priv->clk)) { + ret = clk_prepare_enable(priv->clk); + if (ret) + return ret; + } + if (priv->mask_interrupts) { /* mask the interrupt */ val = readl(priv->base + RNG_INT_MASK);
@@ -79,7 +88,7 @@ static int bcm2835_rng_init(struct hwrng *rng) __raw_writel(RNG_WARMUP_COUNT, priv->base + RNG_STATUS); __raw_writel(RNG_RBGEN, priv->base + RNG_CTRL); - return 0; + return ret; } static void bcm2835_rng_cleanup(struct hwrng *rng)
@@ -88,6 +97,9 @@ static void bcm2835_rng_cleanup(struct hwrng *rng) /* disable rng hardware */ __raw_writel(0, priv->base + RNG_CTRL); + + if (!IS_ERR(priv->clk)) + clk_disable_unprepare(priv->clk); } struct bcm2835_rng_of_data {
@@ -130,6 +142,9 @@ static int bcm2835_rng_probe(struct platform_device *pdev) return PTR_ERR(priv->base); } + /* Clock is optional on most platforms */ + priv->clk = devm_clk_get(dev, NULL); + priv->rng.name = "bcm2835-rng"; priv->rng.init = bcm2835_rng_init; priv->rng.read = bcm2835_rng_read;
--
2.9.3