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Fri, 04 Oct 2019 14:54:13 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 3E51A10002A; Fri, 4 Oct 2019 14:54:13 +0200 (CEST) Received: from Webmail-eu.st.com (Safex1hubcas21.st.com [10.75.90.44]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 3054A2BFDEF; Fri, 4 Oct 2019 14:54:13 +0200 (CEST) Received: from SAFEX1HUBCAS22.st.com (10.75.90.92) by SAFEX1HUBCAS21.st.com (10.75.90.44) with Microsoft SMTP Server (TLS) id 14.3.439.0; Fri, 4 Oct 2019 14:54:13 +0200 Received: from localhost (10.48.0.192) by Webmail-ga.st.com (10.75.90.48) with Microsoft SMTP Server (TLS) id 14.3.439.0; Fri, 4 Oct 2019 14:54:12 +0200 From: Fabrice Gasnier To: , , Subject: [PATCH v2 3/3] pwm: stm32: add power management support Date: Fri, 4 Oct 2019 14:53:53 +0200 Message-ID: <1570193633-6600-4-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1570193633-6600-1-git-send-email-fabrice.gasnier@st.com> References: <1570193633-6600-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 X-Originating-IP: [10.48.0.192] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,1.0.8 definitions=2019-10-04_06:2019-10-03,2019-10-04 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191004_055421_337294_8DC49E46 X-CRM114-Status: GOOD ( 17.12 ) X-Spam-Score: -0.9 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [91.207.212.93 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, alexandre.torgue@st.com, linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org, mcoquelin.stm32@gmail.com, fabrice.gasnier@st.com, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, benjamin.gaignard@st.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Add suspend/resume PM sleep ops. When going to low power, enforce the PWM channel isn't active. Let the PWM consumers disable it during their own suspend sequence, see [1]. So, perform a check here, and handle the pinctrl states. Also restore the break inputs upon resume, as registers content may be lost when going to low power mode. [1] https://lkml.org/lkml/2019/2/5/770 Signed-off-by: Fabrice Gasnier --- Changes in v2: Follow Uwe suggestions/remarks: - Add a precursor patch to ease reviewing - Use registers read instead of pwm_get_state - Add a comment to mention registers content may be lost in low power mode --- drivers/pwm/pwm-stm32.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c index cf8658c..546b661 100644 --- a/drivers/pwm/pwm-stm32.c +++ b/drivers/pwm/pwm-stm32.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -655,6 +656,42 @@ static int stm32_pwm_remove(struct platform_device *pdev) return 0; } +static int __maybe_unused stm32_pwm_suspend(struct device *dev) +{ + struct stm32_pwm *priv = dev_get_drvdata(dev); + unsigned int ch; + u32 ccer, mask; + + /* Look for active channels */ + ccer = active_channels(priv); + + for (ch = 0; ch < priv->chip.npwm; ch++) { + mask = TIM_CCER_CC1E << (ch * 4); + if (ccer & mask) { + dev_err(dev, "The consumer didn't stop us (%s)\n", + priv->chip.pwms[ch].label); + return -EBUSY; + } + } + + return pinctrl_pm_select_sleep_state(dev); +} + +static int __maybe_unused stm32_pwm_resume(struct device *dev) +{ + struct stm32_pwm *priv = dev_get_drvdata(dev); + int ret; + + ret = pinctrl_pm_select_default_state(dev); + if (ret) + return ret; + + /* restore breakinput registers that may have been lost in low power */ + return stm32_pwm_apply_breakinputs(priv); +} + +static SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume); + static const struct of_device_id stm32_pwm_of_match[] = { { .compatible = "st,stm32-pwm", }, { /* end node */ }, @@ -667,6 +704,7 @@ static struct platform_driver stm32_pwm_driver = { .driver = { .name = "stm32-pwm", .of_match_table = stm32_pwm_of_match, + .pm = &stm32_pwm_pm_ops, }, }; module_platform_driver(stm32_pwm_driver);