From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [PATCH v3 10/11] iio: light: cm32181: Add support for parsing CPM0 and CPM1 ACPI tables Date: Mon, 4 May 2020 11:57:30 +0200 Message-ID: References: <20200428172923.567806-1-hdegoede@redhat.com> <20200428172923.567806-10-hdegoede@redhat.com> <20200503122237.4af34181@archlinux> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200503122237.4af34181@archlinux> Content-Language: en-US Sender: linux-acpi-owner@vger.kernel.org To: Jonathan Cameron Cc: "Rafael J . Wysocki" , Len Brown , Darren Hart , Andy Shevchenko , linux-acpi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , linux-iio@vger.kernel.org, Andy Shevchenko List-Id: platform-driver-x86.vger.kernel.org Hi, On 5/3/20 1:22 PM, Jonathan Cameron wrote: > On Tue, 28 Apr 2020 19:29:22 +0200 > Hans de Goede wrote: > >> On ACPI based systems the CPLM3218 ACPI device node describing the >> CM3218[1] sensor typically will have some extra tables with register >> init values for initializing the sensor and calibration info. >> >> This is based on a newer version of cm32181.c, with a copyright of: >> >> * Copyright (C) 2014 Capella Microsystems Inc. >> * Author: Kevin Tsai >> * >> * 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 the following models: Acer Switch 10 SW5-012 (CM32181) >> Asus T100TA (CM3218), Asus T100CHI (CM3218) and HP X2 10-n000nd (CM32181). > > I assume it's far too much to hope this CPM0 / CPM1 stuff is actually defined > in a spec anywhere? > > There are standard way of adding vendor specific data blobs to ACPI and this > isn't one of them (unless I'm missing something). People need to beat > up vendors earlier about this stuff. To be fair, most devices with these sensors are quite old, the T100TA was released in 2013. I have adding support for these on my todo list for quite some time now (years really), but I never got around to it until now. Surprisingly enough, the recent released Chuwi Hi 13 device is also using a CM32181 sensor though, so even though these are old they are still being used. Anyways what I'm trying to say is that the CPM0 / CPM1 objects predate specs for doing this in a more standardized ways by many years. Also the specs to do this in a standardized way are mostly being driven from the ARM side of things and x86 hardware/firmware developers are used to just doing there own things for decades now, so I would not expect them to pick this up anytime soon, sorry. Regards, Hans >> Reviewed-by: Andy Shevchenko >> Signed-off-by: Hans de Goede >> --- >> Changes in v2: >> - Factor out the parsing into a separate helper function >> --- >> drivers/iio/light/cm32181.c | 101 ++++++++++++++++++++++++++++++++++++ >> 1 file changed, 101 insertions(+) >> >> diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c >> index cae2264e4336..d8b128286527 100644 >> --- a/drivers/iio/light/cm32181.c >> +++ b/drivers/iio/light/cm32181.c >> @@ -4,6 +4,7 @@ >> * Author: Kevin Tsai >> */ >> >> +#include >> #include >> #include >> #include >> @@ -53,6 +54,15 @@ >> >> #define SMBUS_ALERT_RESPONSE_ADDRESS 0x0c >> >> +/* CPM0 Index 0: device-id (3218 or 32181), 1: Unknown, 2: init_regs_bitmap */ >> +#define CPM0_REGS_BITMAP 2 >> +#define CPM0_HEADER_SIZE 3 >> + >> +/* CPM1 Index 0: lux_per_bit, 1: calibscale, 2: resolution (100000) */ >> +#define CPM1_LUX_PER_BIT 0 >> +#define CPM1_CALIBSCALE 1 >> +#define CPM1_SIZE 3 >> + >> /* CM3218 Family */ >> static const int cm3218_als_it_bits[] = { 0, 1, 2, 3 }; >> static const int cm3218_als_it_values[] = { 100000, 200000, 400000, 800000 }; >> @@ -65,6 +75,7 @@ static const int cm32181_als_it_values[] = { >> >> struct cm32181_chip { >> struct i2c_client *client; >> + struct device *dev; >> struct mutex lock; >> u16 conf_regs[CM32181_CONF_REG_NUM]; >> unsigned long init_regs_bitmap; >> @@ -76,6 +87,92 @@ struct cm32181_chip { >> const int *als_it_values; >> }; >> >> +static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2); >> + >> +#ifdef CONFIG_ACPI >> +/** >> + * cm32181_acpi_get_cpm() - Get CPM object from ACPI >> + * @client pointer of struct i2c_client. >> + * @obj_name pointer of ACPI object name. >> + * @count maximum size of return array. >> + * @vals pointer of array for return elements. >> + * >> + * Convert ACPI CPM table to array. >> + * >> + * Return: -ENODEV for fail. Otherwise is number of elements. >> + */ >> +static int cm32181_acpi_get_cpm(struct device *dev, char *obj_name, >> + u64 *values, int count) >> +{ >> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; >> + union acpi_object *cpm, *elem; >> + acpi_handle handle; >> + acpi_status status; >> + int i; >> + >> + handle = ACPI_HANDLE(dev); >> + if (!handle) >> + return -ENODEV; >> + >> + status = acpi_evaluate_object(handle, obj_name, NULL, &buffer); >> + if (ACPI_FAILURE(status)) { >> + dev_err(dev, "object %s not found\n", obj_name); >> + return -ENODEV; >> + } >> + >> + cpm = buffer.pointer; >> + if (cpm->package.count > count) >> + dev_warn(dev, "%s table contains %d values, only using first %d values\n", >> + obj_name, cpm->package.count, count); >> + >> + count = min_t(int, cpm->package.count, count); >> + for (i = 0; i < count; i++) { >> + elem = &(cpm->package.elements[i]); >> + values[i] = elem->integer.value; >> + } >> + >> + kfree(buffer.pointer); >> + >> + return count; >> +} >> + >> +static void cm32181_acpi_parse_cpm_tables(struct cm32181_chip *cm32181) >> +{ >> + u64 vals[CPM0_HEADER_SIZE + CM32181_CONF_REG_NUM]; >> + struct device *dev = cm32181->dev; >> + int i, count; >> + >> + count = cm32181_acpi_get_cpm(dev, "CPM0", vals, ARRAY_SIZE(vals)); >> + if (count <= CPM0_HEADER_SIZE) >> + return; >> + >> + count -= CPM0_HEADER_SIZE; >> + >> + cm32181->init_regs_bitmap = vals[CPM0_REGS_BITMAP]; >> + cm32181->init_regs_bitmap &= GENMASK(count - 1, 0); >> + for_each_set_bit(i, &cm32181->init_regs_bitmap, count) >> + cm32181->conf_regs[i] = vals[CPM0_HEADER_SIZE + i]; >> + >> + count = cm32181_acpi_get_cpm(dev, "CPM1", vals, ARRAY_SIZE(vals)); >> + if (count != CPM1_SIZE) >> + return; >> + >> + cm32181->lux_per_bit = vals[CPM1_LUX_PER_BIT]; >> + >> + /* Check for uncalibrated devices */ >> + if (vals[CPM1_CALIBSCALE] == CM32181_CALIBSCALE_DEFAULT) >> + return; >> + >> + cm32181->calibscale = vals[CPM1_CALIBSCALE]; >> + /* CPM1 lux_per_bit is for the current it value */ >> + cm32181_read_als_it(cm32181, &cm32181->lux_per_bit_base_it); >> +} >> +#else >> +static void cm32181_acpi_parse_cpm_tables(struct cm32181_chip *cm32181) >> +{ >> +} >> +#endif /* CONFIG_ACPI */ >> + >> /** >> * cm32181_reg_init() - Initialize CM32181 registers >> * @cm32181: pointer of struct cm32181. >> @@ -119,6 +216,9 @@ static int cm32181_reg_init(struct cm32181_chip *cm32181) >> cm32181->lux_per_bit = CM32181_LUX_PER_BIT; >> cm32181->lux_per_bit_base_it = CM32181_LUX_PER_BIT_BASE_IT; >> >> + if (ACPI_HANDLE(cm32181->dev)) >> + cm32181_acpi_parse_cpm_tables(cm32181); >> + >> /* Initialize registers*/ >> for_each_set_bit(i, &cm32181->init_regs_bitmap, CM32181_CONF_REG_NUM) { >> ret = i2c_smbus_write_word_data(client, i, >> @@ -361,6 +461,7 @@ static int cm32181_probe(struct i2c_client *client) >> >> cm32181 = iio_priv(indio_dev); >> cm32181->client = client; >> + cm32181->dev = dev; >> >> mutex_init(&cm32181->lock); >> indio_dev->dev.parent = dev; >