From: andrew@lunn•ch (Andrew Lunn)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/5] clk: mvebu: Add core-divider clock
Date: Thu, 26 Sep 2013 10:24:04 +0200 [thread overview]
Message-ID: <20130926082404.GA18244@lunn.ch> (raw)
In-Reply-To: <20130925213730.GA19371@localhost>
Hi Ezequiel
> +static int clk_corediv_enable(struct clk_hw *hwclk)
> +{
> + struct clk_corediv *corediv = to_corediv_clk(hwclk);
> + struct clk_corediv_desc *desc = &corediv->desc;
> + u32 reg;
> +
> + reg = readl(corediv->reg);
> + reg |= (BIT(desc->fieldbit) << CORE_CLOCK_DIVIDER_ENABLE_OFFSET);
> + writel(reg, corediv->reg);
> + return 0;
> +}
Shouldn't there be spinlocks around these register accesses? At least
the core gate clk driver has a spinlock.
> +static long clk_corediv_round_rate(struct clk_hw *hwclk, unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + /* Valid ratio are 1:4, 1:5, 1:6 and 1:8 */
> + u32 div;
> +
> + div = *parent_rate / rate;
> + if (div <= 4)
> + div = 4;
> + else if (div <= 5)
> + div = 5;
> + else if (div <= 6)
> + div = 6;
> + else
> + div = 8;
> +
> + return *parent_rate / div;
> +}
This looks odd. Is not the following clearer?
div = *parent_rate / rate;
if (div < 5)
div = 4;
else if (div > 6)
div = 8;
The CodingStyle might require some {} here?
+ /*
+ * Wait for clocks to settle down, and then clear all the
+ * ratios request and the reload request.
+ */
+ udelay(1000);
+ reg &= ~(CORE_CLOCK_DIVIDER_RATIO_MASK | CORE_CLOCK_DIVIDER_RATIO_RELOAD);
+ writel(reg, corediv->reg);
+ udelay(1000);
Documentation/timers/timers-howto.txt says:
SLEEPING FOR ~USECS OR SMALL MSECS ( 10us - 20ms):
* Use usleep_range
Andrew
next prev parent reply other threads:[~2013-09-26 8:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-25 21:28 [PATCH 0/5] Add Core Divider clock support for Armada 370/XP Ezequiel Garcia
2013-09-25 21:28 ` [PATCH 1/5] clk: mvebu: Add core-divider clock Ezequiel Garcia
2013-09-25 21:28 ` [PATCH 2/5] ARM: mvebu: Add Core Divider clock device-tree binding Ezequiel Garcia
2013-09-25 21:28 ` [PATCH 3/5] ARM: mvebu: Add a 2 GHz fixed-clock Armada 370/XP Ezequiel Garcia
2013-09-25 21:28 ` [PATCH 4/5] ARM: mvebu: Add the core-divider clock to " Ezequiel Garcia
2013-09-25 21:28 ` [PATCH 5/5] ARM: mvebu: Add NAND " Ezequiel Garcia
2013-09-25 21:37 ` [PATCH 0/5] Add Core Divider clock support for " Ezequiel Garcia
2013-09-26 7:38 ` Gregory CLEMENT
2013-09-26 15:26 ` Ezequiel Garcia
2013-09-26 15:47 ` Thomas Petazzoni
2013-09-26 16:00 ` Ezequiel Garcia
2013-09-26 16:12 ` Thomas Petazzoni
2013-09-26 8:24 ` Andrew Lunn [this message]
2013-09-26 15:12 ` [PATCH 1/5] clk: mvebu: Add core-divider clock Ezequiel Garcia
2013-09-26 15:56 ` Andrew Lunn
2013-09-26 16:55 ` Ben Dooks
2013-09-26 18:29 ` Ezequiel Garcia
2013-09-26 8:36 ` [PATCH 2/5] ARM: mvebu: Add Core Divider clock device-tree binding Andrew Lunn
2013-09-26 15:04 ` Ezequiel Garcia
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