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received-spf: None (protection.outlook.com: nxp.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: JaamQxk4G4A+hccSgbT3aTuuAafYjkuY65ZzYnFOIQblxCbZe1qlbpJcI5cPT0nu3ofMKsAYLR9zkghodqNlY23CJx3AHW59knHEHFz2B3Zw4Gba0nCKZLuDntMoBH07iPXlWphzMbUXCga0Xn7Vtf1H3Sci2YqmQm1vNTFUT98tOATjaeWjxHR6KWd9VvaKpGpNelXetfe1pt0WXwQv3dk6dwhCC8U3/O0d52V4z9/N8cT4MMbiL882ZZ9ItppJUVIwCfmvrH3zgQcT8VUJDTHOUk9qL+fFySlcfFVJUK/J7vyg0CLJlNssDKvM9QfHNaSTnnKjCIjGRGZL6jO1zlgk+LoE1qBvBN52HN2/sYTxOHAGC5Ii/biDwf6zX/fU07nZNrOTwG7o/Rxex0hyYEGNYIabOTEEr/tZkHzG32k= Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 31915c1d-db0b-4f77-1171-08d72ac70cc4 X-MS-Exchange-CrossTenant-originalarrivaltime: 27 Aug 2019 08:17:50.1446 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: QAq71gkrnoh1/AcRotgSzzX5jZ0h43vi6PEuR8IzdXScqTdTeCB2PVd4YC3FLnefUqRmVumMF2pzHqetUypeaw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM0PR04MB6961 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peng Fan There is hardware issue that: The output clock the LPCG cell will not turn back on as expected, even though a read of the IPG registers in the LPCG indicates that the clock should be enabled. The software workaround is to write twice to enable the LPCG clock output. Signed-off-by: Peng Fan --- drivers/clk/imx/clk-lpcg-scu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/clk/imx/clk-lpcg-scu.c b/drivers/clk/imx/clk-lpcg-scu.= c index a73a799fb777..7391d0668ec4 100644 --- a/drivers/clk/imx/clk-lpcg-scu.c +++ b/drivers/clk/imx/clk-lpcg-scu.c @@ -54,6 +54,11 @@ static int clk_lpcg_scu_enable(struct clk_hw *hw) =20 reg |=3D val << clk->bit_idx; writel(reg, clk->reg); + /* + * There is hardware bug. When enabling the LPCG clock + * output, SW can write the enabling value twice + */ + writel(reg, clk->reg); =20 spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags); =20 @@ -71,6 +76,11 @@ static void clk_lpcg_scu_disable(struct clk_hw *hw) reg =3D readl_relaxed(clk->reg); reg &=3D ~(CLK_GATE_SCU_LPCG_MASK << clk->bit_idx); writel(reg, clk->reg); + /* + * There is hardware bug. When enabling the LPCG clock + * output, SW can write the enabling value twice + */ + writel(reg, clk->reg); =20 spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags); } --=20 2.16.4