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Date:   Mon, 4 May 2020 11:23:42 +0100
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     Hans de Goede <hdegoede@redhat.com>
CC:     Jonathan Cameron <jic23@kernel.org>,
        "Rafael J . Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        <linux-acpi@vger.kernel.org>,
        <platform-driver-x86@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, Hartmut Knaack <knaack.h@gmx.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        <linux-iio@vger.kernel.org>,
        Andy Shevchenko <andy.shevchenko@gmail.com>
Subject: Re: [PATCH v3 04/11] iio: light: cm32181: Add support for the
 CM3218
Message-ID: <20200504112342.00001cac@Huawei.com>
In-Reply-To: <3eae2042-209e-5944-b90e-f747da820ac9@redhat.com>
References: <20200428172923.567806-1-hdegoede@redhat.com>
        <20200428172923.567806-4-hdegoede@redhat.com>
        <20200503115906.6fb86b49@archlinux>
        <3eae2042-209e-5944-b90e-f747da820ac9@redhat.com>
Organization: Huawei Technologies Research and Development (UK) Ltd.
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On Mon, 4 May 2020 11:49:59 +0200
Hans de Goede <hdegoede@redhat.com> wrote:

> Hi,
> 
> On 5/3/20 12:59 PM, Jonathan Cameron wrote:
> > On Tue, 28 Apr 2020 19:29:16 +0200
> > Hans de Goede <hdegoede@redhat.com> wrote:
> >   
> >> Add support for the CM3218 which is an older version of the
> >> CM32181.
> >>
> >> This is based on a newer version of cm32181.c, with a copyright of:
> >>
> >>   * Copyright (C) 2014 Capella Microsystems Inc.
> >>   * Author: Kevin Tsai <ktsai@capellamicro.com>
> >>   *
> >>   * 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.
> >>
> >> Which is floating around on the net in various places, but the changes
> >> from this newer version never made it upstream.
> >>
> >> This was tested on an Asus T100TA and an Asus T100CHI, which both come
> >> with the CM3218 variant of the light sensor.
> >>
> >> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> >> Signed-off-by: Hans de Goede <hdegoede@redhat.com>  
> > 
> > The need to also store the name for the different sensors makes
> > the case for picking between 'chip_info' structures in here stronger.
> > So I'd do that instead of setting multiple elements in your
> > switch statement... (See inline)
> >   
> >> ---
> >>   drivers/iio/light/cm32181.c | 48 +++++++++++++++++++++++++++----------
> >>   1 file changed, 36 insertions(+), 12 deletions(-)
> >>
> >> diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c
> >> index 6fc0a753c499..065bc7a11f84 100644
> >> --- a/drivers/iio/light/cm32181.c
> >> +++ b/drivers/iio/light/cm32181.c
> >> @@ -55,15 +55,24 @@ static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
> >>   	CM32181_REG_ADDR_CMD,
> >>   };
> >>   
> >> -static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
> >> -static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
> >> -	800000};
> >> +/* CM3218 Family */
> >> +static const int cm3218_als_it_bits[] = { 0, 1, 2, 3 };
> >> +static const int cm3218_als_it_values[] = { 100000, 200000, 400000, 800000 };
> >> +
> >> +/* CM32181 Family */
> >> +static const int cm32181_als_it_bits[] = { 12, 8, 0, 1, 2, 3 };
> >> +static const int cm32181_als_it_values[] = {
> >> +	25000, 50000, 100000, 200000, 400000, 800000
> >> +};
> >>   
> >>   struct cm32181_chip {
> >>   	struct i2c_client *client;
> >>   	struct mutex lock;
> >>   	u16 conf_regs[CM32181_CONF_REG_NUM];
> >>   	int calibscale;
> >> +	int num_als_it;
> >> +	const int *als_it_bits;
> >> +	const int *als_it_values;  
> > These are constant for each type of chip and come as a set.
> > Better to just have a cm32181_chip_info structure with all 3 in it
> > (and the name as mentioned earlier).  That way your switch below
> > just becomes a matter of setting a single pointer for each case.  
> 
> Ok I will add a chip_info structure for v4 off the patch-set.
> 
> 
> >   
> >>   };
> >>   
> >>   /**
> >> @@ -85,8 +94,21 @@ static int cm32181_reg_init(struct cm32181_chip *cm32181)
> >>   		return ret;
> >>   
> >>   	/* check device ID */
> >> -	if ((ret & 0xFF) != 0x81)
> >> +	switch (ret & 0xFF) {
> >> +	case 0x18: /* CM3218 */  
> > 
> > I'd ideally like to see a sanity check that we have the part expected.
> > So the compatible matches what we actually get.  
> 
> Erm, so far I've only seen the CM3218 on X86 + ACPI devices which
> use an ACPI id of CPLM3218 for both sensor models, so at least
> on ACPI there is nothing to check.

Groan.  Never mind then.

J 

> 
> Regards,
> 
> Hans
> 
> 
> 
> > 
> > If it doesn't but the part is still one we support print a warning.
> >   
> >> +		cm32181->num_als_it = ARRAY_SIZE(cm3218_als_it_bits);
> >> +		cm32181->als_it_bits = cm3218_als_it_bits;
> >> +		cm32181->als_it_values = cm3218_als_it_values;
> >> +		break;
> >> +	case 0x81: /* CM32181 */
> >> +	case 0x82: /* CM32182, fully compat. with CM32181 */
> >> +		cm32181->num_als_it = ARRAY_SIZE(cm32181_als_it_bits);
> >> +		cm32181->als_it_bits = cm32181_als_it_bits;
> >> +		cm32181->als_it_values = cm32181_als_it_values;
> >> +		break;
> >> +	default:
> >>   		return -ENODEV;
> >> +	}
> >>   
> >>   	/* Default Values */
> >>   	cm32181->conf_regs[CM32181_REG_ADDR_CMD] =
> >> @@ -121,9 +143,9 @@ static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
> >>   	als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
> >>   	als_it &= CM32181_CMD_ALS_IT_MASK;
> >>   	als_it >>= CM32181_CMD_ALS_IT_SHIFT;
> >> -	for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
> >> -		if (als_it == als_it_bits[i]) {
> >> -			*val2 = als_it_value[i];
> >> +	for (i = 0; i < cm32181->num_als_it; i++) {
> >> +		if (als_it == cm32181->als_it_bits[i]) {
> >> +			*val2 = cm32181->als_it_values[i];
> >>   			return IIO_VAL_INT_PLUS_MICRO;
> >>   		}
> >>   	}
> >> @@ -146,14 +168,14 @@ static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
> >>   	u16 als_it;
> >>   	int ret, i, n;
> >>   
> >> -	n = ARRAY_SIZE(als_it_value);
> >> +	n = cm32181->num_als_it;
> >>   	for (i = 0; i < n; i++)
> >> -		if (val <= als_it_value[i])
> >> +		if (val <= cm32181->als_it_values[i])
> >>   			break;
> >>   	if (i >= n)
> >>   		i = n - 1;
> >>   
> >> -	als_it = als_it_bits[i];
> >> +	als_it = cm32181->als_it_bits[i];
> >>   	als_it <<= CM32181_CMD_ALS_IT_SHIFT;
> >>   
> >>   	mutex_lock(&cm32181->lock);
> >> @@ -265,11 +287,12 @@ static int cm32181_write_raw(struct iio_dev *indio_dev,
> >>   static ssize_t cm32181_get_it_available(struct device *dev,
> >>   			struct device_attribute *attr, char *buf)
> >>   {
> >> +	struct cm32181_chip *cm32181 = iio_priv(dev_to_iio_dev(dev));
> >>   	int i, n, len;
> >>   
> >> -	n = ARRAY_SIZE(als_it_value);
> >> +	n = cm32181->num_als_it;
> >>   	for (i = 0, len = 0; i < n; i++)
> >> -		len += sprintf(buf + len, "0.%06u ", als_it_value[i]);
> >> +		len += sprintf(buf + len, "0.%06u ", cm32181->als_it_values[i]);
> >>   	return len + sprintf(buf + len, "\n");
> >>   }
> >>   
> >> @@ -345,6 +368,7 @@ static int cm32181_probe(struct i2c_client *client)
> >>   }
> >>   
> >>   static const struct of_device_id cm32181_of_match[] = {
> >> +	{ .compatible = "capella,cm3218" },
> >>   	{ .compatible = "capella,cm32181" },
> >>   	{ }
> >>   };  
> >   
>