From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751415AbdH3McP convert rfc822-to-8bit (ORCPT ); Wed, 30 Aug 2017 08:32:15 -0400 Received: from mga11.intel.com ([192.55.52.93]:22375 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751318AbdH3McO (ORCPT ); Wed, 30 Aug 2017 08:32:14 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,448,1498546800"; d="scan'208";a="1167573888" From: "Mohandass, Divagar" To: Sakari Ailus CC: "robh+dt@kernel.org" , "mark.rutland@arm.com" , "wsa@the-dreams.de" , "devicetree@vger.kernel.org" , "linux-i2c@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Mani, Rajmohan" Subject: RE: [PATCH v3 3/3] eeprom: at24: enable runtime pm support Thread-Topic: [PATCH v3 3/3] eeprom: at24: enable runtime pm support Thread-Index: AQHTIUYgIm5yxjRWak2Glo+47F6ElqKcK2QAgACh8CA= Date: Wed, 30 Aug 2017 12:32:07 +0000 Message-ID: <7B8CE47BD58441468D2BB13285B50E6031DE621E@BGSMSX107.gar.corp.intel.com> References: <1504066266-30051-1-git-send-email-divagar.mohandass@intel.com> <1504066266-30051-4-git-send-email-divagar.mohandass@intel.com> <20170830075329.cyhzitpfwojq3aox@valkosipuli.retiisi.org.uk> In-Reply-To: <20170830075329.cyhzitpfwojq3aox@valkosipuli.retiisi.org.uk> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-originating-ip: [10.223.10.10] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sakari, Thanks for your time. My comments below. --- ^Divagar >-----Original Message----- >From: Sakari Ailus [mailto:sakari.ailus@iki.fi] >Sent: Wednesday, August 30, 2017 1:24 PM >To: Mohandass, Divagar >Cc: robh+dt@kernel.org; mark.rutland@arm.com; wsa@the-dreams.de; >devicetree@vger.kernel.org; linux-i2c@vger.kernel.org; linux- >kernel@vger.kernel.org; Mani, Rajmohan >Subject: Re: [PATCH v3 3/3] eeprom: at24: enable runtime pm support > >Hi Divagar, > >Thanks for the update. A few more comments below. > >On Wed, Aug 30, 2017 at 09:41:06AM +0530, Divagar Mohandass wrote: >> Currently the device is kept in D0, there is an opportunity to save >> power by enabling runtime pm. >> >> Device can be daisy chained from PMIC and we can't rely on I2C core >> for auto resume/suspend. Driver will decide when to resume/suspend. >> >> Signed-off-by: Divagar Mohandass >> --- >> drivers/misc/eeprom/at24.c | 39 >> +++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 39 insertions(+) >> >> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c >> index 2199c42..a670814 100644 >> --- a/drivers/misc/eeprom/at24.c >> +++ b/drivers/misc/eeprom/at24.c >> @@ -24,6 +24,7 @@ >> #include >> #include >> #include >> +#include >> >> /* >> * I2C EEPROMs from most vendors are inexpensive and mostly >interchangeable. >> @@ -501,11 +502,22 @@ static ssize_t at24_eeprom_write_i2c(struct >> at24_data *at24, const char *buf, static int at24_read(void *priv, >> unsigned int off, void *val, size_t count) { >> struct at24_data *at24 = priv; >> + struct i2c_client *client; >> char *buf = val; >> + int ret; >> >> if (unlikely(!count)) >> return count; >> >> + client = at24_translate_offset(at24, &off); >> + >> + ret = pm_runtime_get_sync(&client->dev); >> + if (ret < 0) { >> + pm_runtime_put_noidle(&client->dev); >> + pm_runtime_put(&client->dev); > >Two puts are too much here. How about dropping this one? Ack Will fix in next version. > >> + return ret; >> + } >> + >> /* >> * Read data from chip, protecting against concurrent updates >> * from this host, but not from other I2C masters. > >If an error happens between the two chunks, you'll need pm_runtime_put(), >too. > Ack >> @@ -527,17 +539,30 @@ static int at24_read(void *priv, unsigned int >> off, void *val, size_t count) >> >> mutex_unlock(&at24->lock); >> >> + pm_runtime_put(&client->dev); >> + >> return 0; >> } >> >> static int at24_write(void *priv, unsigned int off, void *val, size_t >> count) { >> struct at24_data *at24 = priv; >> + struct i2c_client *client; >> char *buf = val; >> + int ret; >> >> if (unlikely(!count)) >> return -EINVAL; >> >> + client = at24_translate_offset(at24, &off); >> + >> + ret = pm_runtime_get_sync(&client->dev); >> + if (ret < 0) { >> + pm_runtime_put_noidle(&client->dev); >> + pm_runtime_put(&client->dev); > >Same here. > Ack >> + return ret; >> + } >> + >> /* >> * Write data to chip, protecting against concurrent updates >> * from this host, but not from other I2C masters. > >Ditto. Ack > >> @@ -559,6 +584,8 @@ static int at24_write(void *priv, unsigned int >> off, void *val, size_t count) >> >> mutex_unlock(&at24->lock); >> >> + pm_runtime_put(&client->dev); >> + >> return 0; >> } >> >> @@ -743,6 +770,15 @@ static int at24_probe(struct i2c_client *client, >> const struct i2c_device_id *id) >> >> i2c_set_clientdata(client, at24); >> >> + /* enable runtime pm */ >> + pm_runtime_get_noresume(&client->dev); >> + err = pm_runtime_set_active(&client->dev); >> + if (err < 0) >> + goto err_clients; >> + >> + pm_runtime_enable(&client->dev); >> + pm_runtime_put(&client->dev); >> + > >You're just about to perform a read here. I believe you should move the last >put after that. At the end of at24_read we are performing a pm_runtime_put, still we need this change ? > >> /* >> * Perform a one-byte test read to verify that the >> * chip is functional. >> @@ -810,6 +846,9 @@ static int at24_remove(struct i2c_client *client) >> for (i = 1; i < at24->num_addresses; i++) >> i2c_unregister_device(at24->client[i]); >> >> + pm_runtime_disable(&client->dev); >> + pm_runtime_set_suspended(&client->dev); >> + >> return 0; >> } >> > >-- >Regards, > >Sakari Ailus >e-mail: sakari.ailus@iki.fi