From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752621AbdA3R0j (ORCPT ); Mon, 30 Jan 2017 12:26:39 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:58226 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750872AbdA3R0e (ORCPT ); Mon, 30 Jan 2017 12:26:34 -0500 From: Alexandre Belloni To: Wolfram Sang Cc: Ludovic Desroches , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexandre Belloni Subject: [PATCH] i2c: at91: ensure state is restored after suspending Date: Mon, 30 Jan 2017 18:25:33 +0100 Message-Id: <20170130172533.31995-1-alexandre.belloni@free-electrons.com> X-Mailer: git-send-email 2.11.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When going to suspend, the I2C registers may be lost because the power to VDDcore is cut. Save them and restore them when resuming. Signed-off-by: Alexandre Belloni --- drivers/i2c/busses/i2c-at91.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c index 0b86c6173e07..633bdd899952 100644 --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -140,6 +140,12 @@ struct at91_twi_dev { unsigned transfer_status; struct i2c_adapter adapter; unsigned twi_cwgr_reg; + struct { + u32 mmr; + u32 imr; + u32 fmr; + u32 fimr; + } cache; struct at91_twi_pdata *pdata; bool use_dma; bool use_alt_cmd; @@ -1172,6 +1178,15 @@ static int at91_twi_runtime_resume(struct device *dev) static int at91_twi_suspend_noirq(struct device *dev) { + struct at91_twi_dev *twi_dev = dev_get_drvdata(dev); + + twi_dev->cache.mmr = at91_twi_read(twi_dev, AT91_TWI_MMR); + twi_dev->cache.imr = at91_twi_read(twi_dev, AT91_TWI_IMR); + if (twi_dev->fifo_size) { + twi_dev->cache.fmr = at91_twi_read(twi_dev, AT91_TWI_FMR); + twi_dev->cache.fimr = at91_twi_read(twi_dev, AT91_TWI_FIMR); + } + if (!pm_runtime_status_suspended(dev)) at91_twi_runtime_suspend(dev); @@ -1180,6 +1195,7 @@ static int at91_twi_suspend_noirq(struct device *dev) static int at91_twi_resume_noirq(struct device *dev) { + struct at91_twi_dev *twi_dev = dev_get_drvdata(dev); int ret; if (!pm_runtime_status_suspended(dev)) { @@ -1191,6 +1207,14 @@ static int at91_twi_resume_noirq(struct device *dev) pm_runtime_mark_last_busy(dev); pm_request_autosuspend(dev); + at91_init_twi_bus(twi_dev); + at91_twi_write(twi_dev, AT91_TWI_MMR, twi_dev->cache.mmr); + at91_twi_write(twi_dev, AT91_TWI_IER, twi_dev->cache.imr); + if (twi_dev->fifo_size) { + at91_twi_write(twi_dev, AT91_TWI_FMR, twi_dev->cache.fmr); + at91_twi_write(twi_dev, AT91_TWI_FIER, twi_dev->cache.fimr); + } + return 0; } -- 2.11.0