Re: [PATCH 2/2] phy: rockchip-emmc: use regmap_read_poll_timeout to poll dllrdy

From: Brian Norris
Date: Thu Jan 04 2018 - 21:07:59 EST


Hi,

On Tue, Jan 02, 2018 at 10:22:00AM +0800, Shawn Lin wrote:
> Just use the API instead of open-coding it, no functional change
> intended.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> ---
>
> drivers/phy/rockchip/phy-rockchip-emmc.c | 21 +++++++--------------
> 1 file changed, 7 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/phy/rockchip/phy-rockchip-emmc.c b/drivers/phy/rockchip/phy-rockchip-emmc.c
> index 512a6ef..c65979b 100644
> --- a/drivers/phy/rockchip/phy-rockchip-emmc.c
> +++ b/drivers/phy/rockchip/phy-rockchip-emmc.c
> @@ -79,6 +79,9 @@
> #define PHYCTRL_IS_CALDONE(x) \
> ((((x) >> PHYCTRL_CALDONE_SHIFT) & \
> PHYCTRL_CALDONE_MASK) == PHYCTRL_CALDONE_DONE)
> +#define PHYCTRL_IS_DLLRDY(x) \
> + ((((x) >> PHYCTRL_DLLRDY_SHIFT) & \
> + PHYCTRL_DLLRDY_MASK) == PHYCTRL_DLLRDY_DONE)
>
> struct rockchip_emmc_phy {
> unsigned int reg_offset;
> @@ -93,7 +96,6 @@ static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
> unsigned int dllrdy;
> unsigned int freqsel = PHYCTRL_FREQSEL_200M;
> unsigned long rate;
> - unsigned long timeout;
>
> /*
> * Keep phyctrl_pdb and phyctrl_endll low to allow
> @@ -222,19 +224,10 @@ static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
> * only at boot / resume. In both cases, eMMC is probably on the
> * critical path so busy waiting a little extra time should be OK.

^^ The above comments talk about busy-waiting, keeping this short, and
critical paths. With a sleeping implementation (like
regmap_read_poll_timeout()) that doesn't quite match, does it? I'd think
you might at least change the wording a little to avoid calling it "busy wait".

Brian

> */
> - timeout = jiffies + msecs_to_jiffies(50);
> - do {
> - udelay(1);
> -
> - regmap_read(rk_phy->reg_base,
> - rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
> - &dllrdy);
> - dllrdy = (dllrdy >> PHYCTRL_DLLRDY_SHIFT) & PHYCTRL_DLLRDY_MASK;
> - if (dllrdy == PHYCTRL_DLLRDY_DONE)
> - break;
> - } while (!time_after(jiffies, timeout));
> -
> - if (dllrdy != PHYCTRL_DLLRDY_DONE) {
> + if (regmap_read_poll_timeout(rk_phy->reg_base,
> + rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
> + dllrdy, PHYCTRL_IS_DLLRDY(dllrdy),
> + 1, 50 * USEC_PER_MSEC)) {
> pr_err("rockchip_emmc_phy_power: dllrdy timeout.\n");
> return -ETIMEDOUT;
> }