Re: [PATCH 06/37] clk: renesas: rzg2l: wait for status bit of SD mux before continuing
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2023-09-14 11:42:23
Also in:
linux-clk, linux-devicetree, linux-gpio, linux-mmc, linux-renesas-soc, linux-serial, lkml
Hi Claudiu, On Tue, Sep 12, 2023 at 6:52 AM Claudiu [off-list ref] wrote:
From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Hardware user manual of RZ/G2L (r01uh0914ej0130-rzg2l-rzg2lc.pdf,
chapter 7.4.7 Procedure for Switching Clocks by the Dynamic Switching
Frequency Selectors) specifies that we need to check CPG_PL2SDHI_DSEL for
SD clock switching status.
Fixes: eaff33646f4cb ("clk: renesas: rzg2l: Add SDHI clk mux support")
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>Thanks for your patch!
quoted hunk ↗ jump to hunk
--- a/drivers/clk/renesas/rzg2l-cpg.c +++ b/drivers/clk/renesas/rzg2l-cpg.c@@ -188,7 +188,8 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index) u32 off = GET_REG_OFFSET(hwdata->conf); u32 shift = GET_SHIFT(hwdata->conf); const u32 clk_src_266 = 2; - u32 bitmask; + u32 msk, val, bitmask; + int ret; /* * As per the HW manual, we should not directly switch from 533 MHz to@@ -203,9 +204,6 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index) */ bitmask = (GENMASK(GET_WIDTH(hwdata->conf) - 1, 0) << shift) << 16; if (index != clk_src_266) { - u32 msk, val; - int ret; - writel(bitmask | ((clk_src_266 + 1) << shift), priv->base + off); msk = off ? CPG_CLKSTATUS_SELSDHI1_STS : CPG_CLKSTATUS_SELSDHI0_STS;@@ -221,7 +219,13 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index) writel(bitmask | ((index + 1) << shift), priv->base + off); - return 0; + ret = readl_poll_timeout(priv->base + CPG_CLKSTATUS, val, + !(val & msk), 100,
"msk" may be uninitialized.
+ CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US); + if (ret) + dev_err(priv->dev, "failed to switch clk source\n"); + + return ret;
This is now (supposed to be) doing the same thing twice, once using clk_src_266, and then again with the wanted index, so why not introduce a small helper? That would have avoided the uninitialized variable, too. I know you're rewriting this code in "[PATCH 18/37] clk: renesas: rzg2l: refactor sd mux driver", but even after that, you always do a register write before calling rzg2l_cpg_wait_clk_update_done(), so it may still be a net win.
} static u8 rzg2l_cpg_sd_clk_mux_get_parent(struct clk_hw *hw)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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