[PATCH v2 05/21] clk: imx: pllv3: add enable() support

Giulio Benetti
2020-01-28T18:46:33Z

On 1/28/20 9:14 AM, Lukasz Majewski wrote:
> Hi Giulio,
>
>> Before set_rate() pllv3 needs enable() to power the pll up.
>> Add enable() taking into account different power_bit and
>> different powerup_set, because some pll needs its power_bit to be
>> set or reset to be powered on.
>
> I do guess that this code is similar to what we do have in the Linux
> kernel (and which I've probably omitted as it was not needed in the
> i.MX6Q use case)?

Exactly, in i.MXRT case need a different enabling sequence and this can
be useful for other i.MX families.

Best regards
--
Giulio Benetti
Benetti Engineering sas

>>
>> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
>> ---
>> drivers/clk/imx/clk-pllv3.c | 24 ++++++++++++++++++++++++
>> 1 file changed, 24 insertions(+)
>>
>> diff --git a/drivers/clk/imx/clk-pllv3.c b/drivers/clk/imx/clk-pllv3.c
>> index 02c75c37ea..d8cbe3dd4e 100644
>> --- a/drivers/clk/imx/clk-pllv3.c
>> +++ b/drivers/clk/imx/clk-pllv3.c
>> @@ -16,9 +16,13 @@
>> #define UBOOT_DM_CLK_IMX_PLLV3_GENERIC "imx_clk_pllv3_generic"
>> #define UBOOT_DM_CLK_IMX_PLLV3_USB "imx_clk_pllv3_usb"
>>
>> +#define BM_PLL_POWER (0x1 << 12)
>> +
>> struct clk_pllv3 {
>> struct clk clk;
>> void __iomem *base;
>> + u32 power_bit;
>> + bool powerup_set;
>> u32 div_mask;
>> u32 div_shift;
>> };
>> @@ -35,8 +39,24 @@ static ulong clk_pllv3_generic_get_rate(struct clk
>> *clk) return (div == 1) ? parent_rate * 22 : parent_rate * 20;
>> }
>>
>> +static int clk_pllv3_generic_enable(struct clk *clk)
>> +{
>> + struct clk_pllv3 *pll = to_clk_pllv3(clk);
>> + u32 val;
>> +
>> + val = readl(pll->base);
>> + if (pll->powerup_set)
>> + val |= pll->power_bit;
>> + else
>> + val &= ~pll->power_bit;
>> + writel(val, pll->base);
>> +
>> + return 0;
>> +}
>> +
>> static const struct clk_ops clk_pllv3_generic_ops = {
>> .get_rate = clk_pllv3_generic_get_rate,
>> + .enable = clk_pllv3_generic_enable,
>> };
>>
>> struct clk *imx_clk_pllv3(enum imx_pllv3_type type, const char *name,
>> @@ -52,14 +72,18 @@ struct clk *imx_clk_pllv3(enum imx_pllv3_type
>> type, const char *name, if (!pll)
>> return ERR_PTR(-ENOMEM);
>>
>> + pll->power_bit = BM_PLL_POWER;
>> +
>> switch (type) {
>> case IMX_PLLV3_GENERIC:
>> drv_name = UBOOT_DM_CLK_IMX_PLLV3_GENERIC;
>> pll->div_shift = 0;
>> + pll->powerup_set = false;
>> break;
>> case IMX_PLLV3_USB:
>> drv_name = UBOOT_DM_CLK_IMX_PLLV3_USB;
>> pll->div_shift = 1;
>> + pll->powerup_set = true;
>> break;
>> default:
>> kfree(pll);
>
>
>
>
> Best regards,
>
> Lukasz Majewski
>
> --
>
> DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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>