From: Peng Fan <peng.fan@nxp.com> To: "mturquette@baylibre.com" <mturquette@baylibre.com>, "sboyd@kernel.org" <sboyd@kernel.org>, "shawnguo@kernel.org" <shawnguo@kernel.org>, "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>, "festevam@gmail.com" <festevam@gmail.com> Cc: "kernel@pengutronix.de" <kernel@pengutronix.de>, dl-linux-imx <linux-imx@nxp.com>, Anson Huang <anson.huang@nxp.com>, Jacky Bai <ping.bai@nxp.com>, Abel Vesa <abel.vesa@nxp.com>, "linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Leonard Crestez <leonard.crestez@nxp.com>, Peng Fan <peng.fan@nxp.com> Subject: [PATCH V2 1/4] clk: imx: pll14xx: avoid glitch when set rate Date: Mon, 26 Aug 2019 09:42:14 +0000 [thread overview] Message-ID: <1566855676-11510-1-git-send-email-peng.fan@nxp.com> (raw) From: Peng Fan <peng.fan@nxp.com> According to PLL1443XA and PLL1416X spec, "When BYPASS is 0 and RESETB is changed from 0 to 1, FOUT starts to output unstable clock until lock time passes. PLL1416X/PLL1443XA may generate a glitch at FOUT." So set BYPASS when RESETB is changed from 0 to 1 to avoid glitch. In the end of set rate, BYPASS will be cleared. When prepare clock, also need to take care to avoid glitch. So we also follow Spec to set BYPASS before RESETB changed from 0 to 1. And add a check if the RESETB is already 0, directly return 0; Fixes: 8646d4dcc7fb ("clk: imx: Add PLLs driver for imx8mm soc") Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com> Signed-off-by: Peng Fan <peng.fan@nxp.com> --- V2: Avoid glitch when prepare update commit log drivers/clk/imx/clk-pll14xx.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/clk/imx/clk-pll14xx.c b/drivers/clk/imx/clk-pll14xx.c index b7213023b238..656f48b002dd 100644 --- a/drivers/clk/imx/clk-pll14xx.c +++ b/drivers/clk/imx/clk-pll14xx.c @@ -191,6 +191,10 @@ static int clk_pll1416x_set_rate(struct clk_hw *hw, unsigned long drate, tmp &= ~RST_MASK; writel_relaxed(tmp, pll->base); + /* Enable BYPASS */ + tmp |= BYPASS_MASK; + writel(tmp, pll->base); + div_val = (rate->mdiv << MDIV_SHIFT) | (rate->pdiv << PDIV_SHIFT) | (rate->sdiv << SDIV_SHIFT); writel_relaxed(div_val, pll->base + 0x4); @@ -250,6 +254,10 @@ static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate, tmp &= ~RST_MASK; writel_relaxed(tmp, pll->base); + /* Enable BYPASS */ + tmp |= BYPASS_MASK; + writel_relaxed(tmp, pll->base); + div_val = (rate->mdiv << MDIV_SHIFT) | (rate->pdiv << PDIV_SHIFT) | (rate->sdiv << SDIV_SHIFT); writel_relaxed(div_val, pll->base + 0x4); @@ -283,16 +291,28 @@ static int clk_pll14xx_prepare(struct clk_hw *hw) { struct clk_pll14xx *pll = to_clk_pll14xx(hw); u32 val; + int ret; /* * RESETB = 1 from 0, PLL starts its normal * operation after lock time */ val = readl_relaxed(pll->base + GNRL_CTL); + if (val & RST_MASK) + return 0; + val |= BYPASS_MASK; + writel_relaxed(val, pll->base + GNRL_CTL); val |= RST_MASK; writel_relaxed(val, pll->base + GNRL_CTL); - return clk_pll14xx_wait_lock(pll); + ret = clk_pll14xx_wait_lock(pll); + if (ret) + return ret; + + val &= ~BYPASS_MASK; + writel_relaxed(val, pll->base + GNRL_CTL); + + return 0; } static int clk_pll14xx_is_prepared(struct clk_hw *hw) -- 2.16.4
WARNING: multiple messages have this Message-ID (diff)
From: Peng Fan <peng.fan@nxp.com> To: "mturquette@baylibre.com" <mturquette@baylibre.com>, "sboyd@kernel.org" <sboyd@kernel.org>, "shawnguo@kernel.org" <shawnguo@kernel.org>, "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>, "festevam@gmail.com" <festevam@gmail.com> Cc: Peng Fan <peng.fan@nxp.com>, Abel Vesa <abel.vesa@nxp.com>, Anson Huang <anson.huang@nxp.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, dl-linux-imx <linux-imx@nxp.com>, "kernel@pengutronix.de" <kernel@pengutronix.de>, Leonard Crestez <leonard.crestez@nxp.com>, "linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, Jacky Bai <ping.bai@nxp.com> Subject: [PATCH V2 1/4] clk: imx: pll14xx: avoid glitch when set rate Date: Mon, 26 Aug 2019 09:42:14 +0000 [thread overview] Message-ID: <1566855676-11510-1-git-send-email-peng.fan@nxp.com> (raw) From: Peng Fan <peng.fan@nxp.com> According to PLL1443XA and PLL1416X spec, "When BYPASS is 0 and RESETB is changed from 0 to 1, FOUT starts to output unstable clock until lock time passes. PLL1416X/PLL1443XA may generate a glitch at FOUT." So set BYPASS when RESETB is changed from 0 to 1 to avoid glitch. In the end of set rate, BYPASS will be cleared. When prepare clock, also need to take care to avoid glitch. So we also follow Spec to set BYPASS before RESETB changed from 0 to 1. And add a check if the RESETB is already 0, directly return 0; Fixes: 8646d4dcc7fb ("clk: imx: Add PLLs driver for imx8mm soc") Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com> Signed-off-by: Peng Fan <peng.fan@nxp.com> --- V2: Avoid glitch when prepare update commit log drivers/clk/imx/clk-pll14xx.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/clk/imx/clk-pll14xx.c b/drivers/clk/imx/clk-pll14xx.c index b7213023b238..656f48b002dd 100644 --- a/drivers/clk/imx/clk-pll14xx.c +++ b/drivers/clk/imx/clk-pll14xx.c @@ -191,6 +191,10 @@ static int clk_pll1416x_set_rate(struct clk_hw *hw, unsigned long drate, tmp &= ~RST_MASK; writel_relaxed(tmp, pll->base); + /* Enable BYPASS */ + tmp |= BYPASS_MASK; + writel(tmp, pll->base); + div_val = (rate->mdiv << MDIV_SHIFT) | (rate->pdiv << PDIV_SHIFT) | (rate->sdiv << SDIV_SHIFT); writel_relaxed(div_val, pll->base + 0x4); @@ -250,6 +254,10 @@ static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate, tmp &= ~RST_MASK; writel_relaxed(tmp, pll->base); + /* Enable BYPASS */ + tmp |= BYPASS_MASK; + writel_relaxed(tmp, pll->base); + div_val = (rate->mdiv << MDIV_SHIFT) | (rate->pdiv << PDIV_SHIFT) | (rate->sdiv << SDIV_SHIFT); writel_relaxed(div_val, pll->base + 0x4); @@ -283,16 +291,28 @@ static int clk_pll14xx_prepare(struct clk_hw *hw) { struct clk_pll14xx *pll = to_clk_pll14xx(hw); u32 val; + int ret; /* * RESETB = 1 from 0, PLL starts its normal * operation after lock time */ val = readl_relaxed(pll->base + GNRL_CTL); + if (val & RST_MASK) + return 0; + val |= BYPASS_MASK; + writel_relaxed(val, pll->base + GNRL_CTL); val |= RST_MASK; writel_relaxed(val, pll->base + GNRL_CTL); - return clk_pll14xx_wait_lock(pll); + ret = clk_pll14xx_wait_lock(pll); + if (ret) + return ret; + + val &= ~BYPASS_MASK; + writel_relaxed(val, pll->base + GNRL_CTL); + + return 0; } static int clk_pll14xx_is_prepared(struct clk_hw *hw) -- 2.16.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2019-08-26 9:42 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-26 9:42 Peng Fan [this message] 2019-08-26 9:42 ` [PATCH V2 1/4] clk: imx: pll14xx: avoid glitch when set rate Peng Fan 2019-08-26 9:42 ` [PATCH V2 2/4] clk: imx: clk-pll14xx: unbypass PLL by default Peng Fan 2019-08-26 9:42 ` Peng Fan 2019-08-26 9:42 ` [PATCH V2 3/4] clk: imx: imx8mm: fix pll mux bit Peng Fan 2019-08-26 9:42 ` Peng Fan 2019-08-26 9:42 ` [PATCH V2 4/4] clk: imx: imx8mn: " Peng Fan 2019-08-26 9:42 ` Peng Fan 2019-09-06 17:21 ` [PATCH V2 1/4] clk: imx: pll14xx: avoid glitch when set rate Stephen Boyd 2019-09-06 17:21 ` Stephen Boyd 2019-09-09 3:40 ` Peng Fan 2019-09-09 3:40 ` Peng Fan
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