2022-09-29 13:39:37

by Tomer Maimon

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Subject: [PATCH v2 2/2] hwrng: npcm: Add NPCM8XX support

Adding RNG NPCM8XX support to NPCM RNG driver.
RNG NPCM8XX uses a different clock prescaler.

As part of adding NPCM8XX support:
- Add NPCM8XX specific compatible string.
- Add data to handle architecture specific clock prescaler.

Signed-off-by: Tomer Maimon <[email protected]>
---
drivers/char/hw_random/npcm-rng.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/char/hw_random/npcm-rng.c b/drivers/char/hw_random/npcm-rng.c
index 1ec5f267a656..5bf7f370f985 100644
--- a/drivers/char/hw_random/npcm-rng.c
+++ b/drivers/char/hw_random/npcm-rng.c
@@ -13,11 +13,13 @@
#include <linux/delay.h>
#include <linux/of_irq.h>
#include <linux/pm_runtime.h>
+#include <linux/of_device.h>

#define NPCM_RNGCS_REG 0x00 /* Control and status register */
#define NPCM_RNGD_REG 0x04 /* Data register */
#define NPCM_RNGMODE_REG 0x08 /* Mode register */

+#define NPCM_RNG_CLK_SET_62_5MHZ BIT(2) /* 60-80 MHz */
#define NPCM_RNG_CLK_SET_25MHZ GENMASK(4, 3) /* 20-25 MHz */
#define NPCM_RNG_DATA_VALID BIT(1)
#define NPCM_RNG_ENABLE BIT(0)
@@ -31,14 +33,14 @@
struct npcm_rng {
void __iomem *base;
struct hwrng rng;
+ u32 clkp;
};

static int npcm_rng_init(struct hwrng *rng)
{
struct npcm_rng *priv = to_npcm_rng(rng);

- writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE,
- priv->base + NPCM_RNGCS_REG);
+ writel(priv->clkp | NPCM_RNG_ENABLE, priv->base + NPCM_RNGCS_REG);

return 0;
}
@@ -47,7 +49,7 @@ static void npcm_rng_cleanup(struct hwrng *rng)
{
struct npcm_rng *priv = to_npcm_rng(rng);

- writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG);
+ writel(priv->clkp, priv->base + NPCM_RNGCS_REG);
}

static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -110,6 +112,7 @@ static int npcm_rng_probe(struct platform_device *pdev)
priv->rng.read = npcm_rng_read;
priv->rng.priv = (unsigned long)&pdev->dev;
priv->rng.quality = 1000;
+ priv->clkp = (u32)(uintptr_t)of_device_get_match_data(&pdev->dev);

writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);

@@ -162,7 +165,10 @@ static const struct dev_pm_ops npcm_rng_pm_ops = {
};

static const struct of_device_id rng_dt_id[] __maybe_unused = {
- { .compatible = "nuvoton,npcm750-rng", },
+ { .compatible = "nuvoton,npcm750-rng",
+ .data = (void *)NPCM_RNG_CLK_SET_25MHZ },
+ { .compatible = "nuvoton,npcm845-rng",
+ .data = (void *)NPCM_RNG_CLK_SET_62_5MHZ },
{},
};
MODULE_DEVICE_TABLE(of, rng_dt_id);
--
2.33.0