Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752815AbcDCJQk (ORCPT ); Sun, 3 Apr 2016 05:16:40 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:48708 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751978AbcDCJQj (ORCPT ); Sun, 3 Apr 2016 05:16:39 -0400 Subject: Re: [PATCH 1/2] ti-adc081c: Add support for adc101c* and adc121c* To: Crestez Dan Leonard , linux-iio@vger.kernel.org References: <001c9c6fb78bcc944a89ab7af8648a2c19ac77e9.1459444547.git.leonard.crestez@intel.com> Cc: linux-kernel@vger.kernel.org, Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Daniel Baluta , Thierry Reding From: Jonathan Cameron Message-ID: <5700DF74.4030709@kernel.org> Date: Sun, 3 Apr 2016 10:16:36 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.1 MIME-Version: 1.0 In-Reply-To: <001c9c6fb78bcc944a89ab7af8648a2c19ac77e9.1459444547.git.leonard.crestez@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4819 Lines: 142 On 31/03/16 18:20, Crestez Dan Leonard wrote: > These chips has an almost identical interface but a deal with a > different number of value bits. Datasheet links for comparison: > > * http://www.ti.com/lit/ds/symlink/adc081c021.pdf > * http://www.ti.com/lit/ds/symlink/adc101c021.pdf > * http://www.ti.com/lit/ds/symlink/adc121c021.pdf > > Signed-off-by: Crestez Dan Leonard Just one query inline. J > --- > drivers/iio/adc/Kconfig | 6 +++--- > drivers/iio/adc/ti-adc081c.c | 31 +++++++++++++++++++++++++++---- > 2 files changed, 30 insertions(+), 7 deletions(-) > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index 9ddcd5d..a2d0db5 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -378,11 +378,11 @@ config ROCKCHIP_SARADC > module will be called rockchip_saradc. > > config TI_ADC081C > - tristate "Texas Instruments ADC081C021/027" > + tristate "Texas Instruments ADC081C/ADC101C/ADC121C family" > depends on I2C > help > - If you say yes here you get support for Texas Instruments ADC081C021 > - and ADC081C027 ADC chips. > + If you say yes here you get support for Texas Instruments ADC081C, > + ADC101C and ADC121C ADC chips. > > This driver can also be built as a module. If so, the module will be > called ti-adc081c. > diff --git a/drivers/iio/adc/ti-adc081c.c b/drivers/iio/adc/ti-adc081c.c > index ecbc121..9b2f26f 100644 > --- a/drivers/iio/adc/ti-adc081c.c > +++ b/drivers/iio/adc/ti-adc081c.c > @@ -1,9 +1,21 @@ > /* > + * TI ADC081C/ADC101C/ADC121C 8/10/12-bit ADC driver > + * > * Copyright (C) 2012 Avionic Design GmbH > + * Copyright (C) 2016 Intel > * > * This program is free software; you can redistribute it and/or modify > * it under the terms of the GNU General Public License version 2 as > * published by the Free Software Foundation. > + * > + * Datasheets: > + * http://www.ti.com/lit/ds/symlink/adc081c021.pdf > + * http://www.ti.com/lit/ds/symlink/adc101c021.pdf > + * http://www.ti.com/lit/ds/symlink/adc121c021.pdf > + * > + * The devices have a very similar interface and differ mostly in the number of > + * bits handled. For the 8-bit and 10-bit models the least-significant 4 or 2 > + * bits of value registers are reserved. > */ > > #include > @@ -17,6 +29,9 @@ > struct adc081c { > struct i2c_client *i2c; > struct regulator *ref; > + > + /* 8, 10 or 12 */ > + int bits; > }; > > #define REG_CONV_RES 0x00 > @@ -34,7 +49,7 @@ static int adc081c_read_raw(struct iio_dev *iio, > if (err < 0) > return err; > > - *value = (err >> 4) & 0xff; > + *value = (err & 0xFFF) >> (12 - adc->bits); > return IIO_VAL_INT; > > case IIO_CHAN_INFO_SCALE: > @@ -43,7 +58,7 @@ static int adc081c_read_raw(struct iio_dev *iio, > return err; > > *value = err / 1000; > - *shift = 8; > + *shift = adc->bits; > > return IIO_VAL_FRACTIONAL_LOG2; > > @@ -72,6 +87,9 @@ static int adc081c_probe(struct i2c_client *client, > struct adc081c *adc; > int err; > > + if (id->driver_data != 8 && id->driver_data != 10 && id->driver_data != 12) > + return -EINVAL; How could this condition occur? The driver won't be probed if we don't have a match on one of the items in the id table and they all obey this rull? On Peter's comment, it would be future proofing to use an index into a information structure array, but I'd prefer that to be added when needed and am reasonably happy with how you have it here. > + > if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) > return -EOPNOTSUPP; > > @@ -81,6 +99,7 @@ static int adc081c_probe(struct i2c_client *client, > > adc = iio_priv(iio); > adc->i2c = client; > + adc->bits = id->driver_data; > > adc->ref = devm_regulator_get(&client->dev, "vref"); > if (IS_ERR(adc->ref)) > @@ -124,7 +143,9 @@ static int adc081c_remove(struct i2c_client *client) > } > > static const struct i2c_device_id adc081c_id[] = { > - { "adc081c", 0 }, > + { "adc081c", 8 }, > + { "adc101c", 10 }, > + { "adc121c", 12 }, > { } > }; > MODULE_DEVICE_TABLE(i2c, adc081c_id); > @@ -132,6 +153,8 @@ MODULE_DEVICE_TABLE(i2c, adc081c_id); > #ifdef CONFIG_OF > static const struct of_device_id adc081c_of_match[] = { > { .compatible = "ti,adc081c" }, > + { .compatible = "ti,adc101c" }, > + { .compatible = "ti,adc121c" }, > { } > }; > MODULE_DEVICE_TABLE(of, adc081c_of_match); > @@ -149,5 +172,5 @@ static struct i2c_driver adc081c_driver = { > module_i2c_driver(adc081c_driver); > > MODULE_AUTHOR("Thierry Reding "); > -MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver"); > +MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver"); > MODULE_LICENSE("GPL v2"); >