[PATCH v3 01/11] clk: davinci - add main PLL clock driver
Sekhar Nori
nsekhar at ti.com
Wed Oct 31 08:29:34 EDT 2012
Hi Murali,
On 10/25/2012 9:41 PM, Murali Karicheri wrote:
> This is the driver for the main PLL clock hardware found on DM SoCs.
> This driver borrowed code from arch/arm/mach-davinci/clock.c and
> implemented the driver as per common clock provider API. The main PLL
> hardware typically has a multiplier, a pre-divider and a post-divider.
> Some of the SoCs has the divider fixed meaning they can not be
> configured through a register. HAS_PREDIV and HAS_POSTDIV flags are used
> to tell the driver if a hardware has these dividers present or not.
> Driver is configured through the struct clk_pll_data that has the
> SoC specific clock data.
>
> Signed-off-by: Murali Karicheri <m-karicheri2 at ti.com>
> ---
> diff --git a/drivers/clk/davinci/clk-pll.c b/drivers/clk/davinci/clk-pll.c
> +static unsigned long clk_pllclk_recalc(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct clk_pll *pll = to_clk_pll(hw);
> + struct clk_pll_data *pll_data = pll->pll_data;
> + u32 mult = 1, prediv = 1, postdiv = 1;
No need to initialize mult here. I gave this comment last time around as
well.
> + unsigned long rate = parent_rate;
> +
> + mult = readl(pll_data->reg_pllm);
> +
> + /*
> + * if fixed_multiplier is non zero, multiply pllm value by this
> + * value.
> + */
> + if (pll_data->fixed_multiplier)
> + mult = pll_data->fixed_multiplier *
> + (mult & pll_data->pllm_mask);
> + else
> + mult = (mult & pll_data->pllm_mask) + 1;
Hmm, this is interpreting the 'mult' register field differently in both
cases. In one case it is 'actual multiplier - 1' and in other case it is
the 'actual multiplier' itself. Can we be sure that the mult register
definition will change whenever there is a fixed multiplier in the PLL
block? I don't think any of the existing DaVinci devices have a fixed
multiplier. Is this on keystone?
> +struct clk *clk_register_davinci_pll(struct device *dev, const char *name,
> + const char *parent_name,
> + struct clk_pll_data *pll_data)
> +{
> + struct clk_init_data init;
> + struct clk_pll *pll;
> + struct clk *clk;
> +
> + if (!pll_data)
> + return ERR_PTR(-ENODEV);
-EINVAL? Clearly you are treating NULL value as an invalid argument here.
Thanks,
Sekhar
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