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SubjectRe: [PATCH 7/8] iio: light: cm32181: Add support for parsing CPM0 and CPM1 ACPI tables
On Sun, Apr 26, 2020 at 2:03 PM Hans de Goede <hdegoede@redhat.com> 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 <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 the following models: Acer Switch 10 SW5-012 (CM32181)
> Asus T100TA (CM3218), Asus T100CHI (CM3218) and HP X2 10-n000nd (CM32181).
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> drivers/iio/light/cm32181.c | 98 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 98 insertions(+)
>
> diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c
> index e5674d4a8143..878fc13632d8 100644
> --- a/drivers/iio/light/cm32181.c
> +++ b/drivers/iio/light/cm32181.c
> @@ -4,6 +4,7 @@
> * Author: Kevin Tsai <ktsai@capellamicro.com>
> */
>
> +#include <linux/acpi.h>
> #include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/i2c.h>
> @@ -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 };
> @@ -76,6 +86,56 @@ 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 i2c_client *client, 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(&client->dev);
> + if (!handle)
> + return -ENODEV;
> +
> + status = acpi_evaluate_object(handle, obj_name, NULL, &buffer);
> + if (ACPI_FAILURE(status)) {
> + dev_err(&client->dev, "object %s not found\n", obj_name);
> + return -ENODEV;
> + }
> +
> + cpm = buffer.pointer;
> + if (cpm->package.count > count)
> + dev_warn(&client->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;
> +}
> +#endif /* CONFIG_ACPI */
> +
> /**
> * cm32181_reg_init() - Initialize CM32181 registers
> * @cm32181: pointer of struct cm32181.
> @@ -121,6 +181,44 @@ 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;
>
> +#ifdef CONFIG_ACPI
> + if (ACPI_HANDLE(&client->dev)) {
> + u64 values[CPM0_HEADER_SIZE + CM32181_CONF_REG_NUM];
> + int count;
> +
> + count = cm32181_acpi_get_cpm(client, "CPM0",
> + values, ARRAY_SIZE(values));
> + if (count <= CPM0_HEADER_SIZE)
> + goto cpm_parsing_done;
> +
> + count -= CPM0_HEADER_SIZE;
> +
> + cm32181->init_regs_bitmap = values[CPM0_REGS_BITMAP];
> + cm32181->init_regs_bitmap &= GENMASK(count - 1, 0);
> + for (i = 0; i < count; i++) {
> + if (cm32181->init_regs_bitmap & BIT(i))
> + cm32181->conf_regs[i] =
> + values[CPM0_HEADER_SIZE + i];
> + }
> +
> + count = cm32181_acpi_get_cpm(client, "CPM1",
> + values, ARRAY_SIZE(values));
> + if (count != CPM1_SIZE)
> + goto cpm_parsing_done;
> +
> + cm32181->lux_per_bit = values[CPM1_LUX_PER_BIT];
> +
> + /* Check for uncalibrated devices */
> + if (values[CPM1_CALIBSCALE] == CM32181_CALIBSCALE_DEFAULT)
> + goto cpm_parsing_done;
> +
> + cm32181->calibscale = values[CPM1_CALIBSCALE];
> + /* CPM1 lux_per_bit is for the current it value */
> + cm32181_read_als_it(cm32181, &cm32181->lux_per_bit_base_it);
> + }
> +cpm_parsing_done:

Perhaps factor out to a helper, will
a) allow to get rid of a label;
b) drop indentation level.

> +#endif /* CONFIG_ACPI */
> +
> /* Initialize registers*/
> for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
> if (cm32181->init_regs_bitmap & BIT(i)) {
> --
> 2.26.0
>


--
With Best Regards,
Andy Shevchenko

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