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Date: Mon, 1 Mar 2021 13:49:49 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Joe Sandom <joe.g.sandom@...il.com>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Meerwald-Stadler <pmeerw@...erw.net>,
Rob Herring <robh+dt@...nel.org>,
Joe Sandom <joe.sandom@...look.com>,
linux-iio <linux-iio@...r.kernel.org>,
devicetree <devicetree@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND][PATCH v4 1/2] Added AMS tsl2591 driver implementation
On Sat, Feb 27, 2021 at 6:58 PM Jonathan Cameron <jic23@...nel.org> wrote:
> On Mon, 22 Feb 2021 21:23:12 +0000
> Joe Sandom <joe.g.sandom@...il.com> wrote:
I will give my review on top of Jonathan's ones.
...
> > Datasheet Available at: https://ams.com/tsl25911
Can we use Datasheet tag, please?
Datasheet: <URL>
> >
...and drop this blank line.
> > Signed-off-by: Joe Sandom <joe.g.sandom@...il.com>
...
> > +config TSL2591
> > + tristate "TAOS TSL2591 ambient light sensor"
> > + depends on I2C
> > + help
> > + Select Y here for support of the AMS/TAOS TSL2591 ambient light sensor,
> > + featuring channels for combined visible + IR intensity and lux illuminance.
> > + Access als data via iio and sysfs. Supports iio_events.
"Access data via IIO ad sysfs."
> > + To compile this driver as a module, select M: the
> > + module will be called tsl2591.
...
> > +/* ALS integration time field value to als time*/
Besides missing space the phrase confuses me (mostly due to "ALS ...
als..." passage).
> > +#define TSL2591_FVAL_TO_ATIME(x) (((x) + 1) * 100)
...
> > +/* TSL2591 command register definitions */
> > +#define TSL2591_CMD_NOP (BIT(5) | BIT(7))
> > +#define TSL2591_CMD_SF_INTSET (BIT(2) | GENMASK(7, 5))
> > +#define TSL2591_CMD_SF_CALS_I (BIT(0) | BIT(2) | GENMASK(7, 5))
> > +#define TSL2591_CMD_SF_CALS_NPI (GENMASK(2, 0) | GENMASK(7, 5))
> > +#define TSL2591_CMD_SF_CNP_ALSI (BIT(1) | BIT(3) | GENMASK(7, 5))
If it's a bit combination, describe each bit field separately, but my
guts are telling me that BIT() and GENMASK() use here is wrong.
...
> > +/* TSL2591 enable register definitions */
> > +#define TSL2591_PWR_ON BIT(0)
> > +#define TSL2591_PWR_OFF 0x00
Similar to above, here you rather use (1 << 0) and (0 << 0), or plain numbers.
...
> > +#define TSL2591_CTRL_ALS_INTEGRATION_100MS 0x00
> > +#define TSL2591_CTRL_ALS_INTEGRATION_200MS BIT(0)
> > +#define TSL2591_CTRL_ALS_INTEGRATION_300MS BIT(1)
> > +#define TSL2591_CTRL_ALS_INTEGRATION_400MS GENMASK(1, 0)
> > +#define TSL2591_CTRL_ALS_INTEGRATION_500MS BIT(2)
> > +#define TSL2591_CTRL_ALS_INTEGRATION_600MS (BIT(0) | BIT(2))
Similar to the above. Drop all BIT() / GENMASK() use here and convert
to plain numbers.
...
> > +#define TSL2591_CTRL_ALS_LOW_GAIN 0x00
> > +#define TSL2591_CTRL_ALS_MED_GAIN BIT(4)
> > +#define TSL2591_CTRL_ALS_HIGH_GAIN BIT(5)
Ditto. And so on. Please, revisit all descriptions above and below.
...
> > +#define TSL2591_ALS_MAX_VALUE 65535
If it's limited by the amount of bits in use, I prefer to spell it as
(BIT(16) - 1), and we will immediately see this implication.
...
> > +/*
> > + * Period table is ALS persist cycle x integration time setting
> > + * Integration times: 100ms, 200ms, 300ms, 400ms, 500ms, 600ms
> > + * ALS cycles: 1, 2, 3, 5, 10, 20, 25, 30, 35, 40, 45, 50, 55, 60
> > + */
> > +static const char * const tsl2591_als_period_list[] = {
> > + "0.1 0.2 0.3 0.5 1.0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0",
> > + "0.2 0.4 0.6 1.0 2.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0",
> > + "0.3 0.6 0.9 1.5 3.0 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5 18.0",
> > + "0.4 0.8 1.2 2.0 4.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0",
> > + "0.5 1.0 1.5 2.5 5.0 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0",
> > + "0.6 1.2 1.8 3.0 6.0 12.0 15.0 18.0 21.0 24.0 27.0 30.0 33.0 36.0",
> > +};
Okay... But it can be generated I guess.
...
> > +static int tsl2591_als_time_to_fval(const u32 als_integration_time)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(tsl2591_int_time_available); ++i) {
> > + if (als_integration_time == tsl2591_int_time_available[i])
> > + return ((als_integration_time / 100) - 1);
Looks like a reversed function of a macro you have above. Care to
introduce a counterpart macro instead and use it here?
> > + if (i == (ARRAY_SIZE(tsl2591_int_time_available) - 1))
> > + break;
This doesn't make any sense to me.
> > + }
> > +
> > + return -EINVAL;
> > +}
...
> > +static int tsl2591_wait_adc_complete(struct tsl2591_chip *chip)
> > +{
> > + struct i2c_client *client = chip->client;
> > + struct tsl2591_als_settings settings = chip->als_settings;
> > + int delay = TSL2591_FVAL_TO_ATIME(settings.als_int_time);
Move the assignment closer to the conditional below.
> > + int ret;
> > + int i;
> > +
> > + if (!delay)
> > + return -EINVAL;
> > +
> > + /*
> > + * Sleep for ALS integration time to allow enough time
> > + * for an ADC read cycle to complete. Check status after
> > + * delay for ALS valid
Missed period.
> > + */
> > + msleep(delay);
> > +
> > + /* Check for status ALS valid flag for up to 100ms */
> > + for (i = 0; i < TSL2591_ALS_STS_VALID_COUNT; ++i) {
i++ works perfectly.
> > + ret = i2c_smbus_read_byte_data(client,
> > + TSL2591_CMD_NOP | TSL2591_STATUS);
> > + if (ret < 0) {
> > + dev_err(&client->dev, "Failed to read register\n");
> > + return -EINVAL;
> > + }
> > + ret = FIELD_GET(TSL2591_STS_ALS_VALID_MASK, ret);
> > + if (ret == TSL2591_STS_VAL_HIGH_MASK)
> > + break;
> > +
> > + if (i == (TSL2591_ALS_STS_VALID_COUNT - 1))
In many cases you added too many parentheses. It's not a LISP language :-)
> > + return -ENODATA;
> > +
> > + usleep_range(9000, 10000);
> > + }
This can be done using iopoll.h and readx_poll_timeout() helper.
> > + return 0;
> > +}
...
> > +static int tsl2591_read_channel_data(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int *val, int *val2)
> > +{
> > + struct tsl2591_chip *chip = iio_priv(indio_dev);
> > + struct tsl2591_als_settings *settings = &chip->als_settings;
> > + struct i2c_client *client = chip->client;
> > + int ret;
> > + u8 als_data[TSL2591_NUM_DATA_REGISTERS];
Try to keep reversed xmas tree order in the definition block(s).
> > +
This should not be here.
> > + int counts_per_lux;
> > + int lux;
> > + int gain_multi;
> > + int int_time_fval;
> > +
Ditto.
> > + u16 als_ch0;
> > + u16 als_ch1;
> > +
> > + ret = tsl2591_wait_adc_complete(chip);
> > + if (ret < 0) {
> > + dev_err(&client->dev, "No data available. Err: %d\n", ret);
> > + return ret;
> > + }
> > +
> > + ret = i2c_smbus_read_i2c_block_data(client,
> > + TSL2591_CMD_NOP | TSL2591_C0_DATAL,
> > + sizeof(als_data), als_data);
> > + if (ret < 0) {
> > + dev_err(&client->dev, "Failed to read data bytes");
> > + return ret;
> For comment below if (ret), that won't work on these calls because IIRC they
> return the number of bytes transferred. However, you can move the check locally
> that this is the right length and ensure 0 is returned for the good path.
> > + }
> > + als_ch0 = le16_to_cpup((const __le16 *)&als_data[0]);
> > + als_ch1 = le16_to_cpup((const __le16 *)&als_data[2]);
The casting looks wrong. Why do you need it? Perhaps your type of
als_data is not okay? Or perhaps you need to use get_unaligned_le16()?
I dunno.
> > + switch (chan->type) {
> > + case IIO_INTENSITY:
> > + if (chan->channel2 == IIO_MOD_LIGHT_BOTH)
> > + *val = als_ch0;
> > + else if (chan->channel2 == IIO_MOD_LIGHT_IR)
> > + *val = als_ch1;
> > + else
> > + return -EINVAL;
> > + break;
> > + case IIO_LIGHT:
> > + gain_multi = tsl2591_gain_to_multiplier(settings->als_gain);
> > + if (gain_multi < 0) {
> > + dev_err(&client->dev, "Invalid multiplier");
> > + return gain_multi;
> > + }
> > +
> > + int_time_fval = TSL2591_FVAL_TO_ATIME(settings->als_int_time);
> > + /* Calculate counts per lux value */
> > + counts_per_lux =
> > + (int_time_fval * gain_multi) / TSL2591_LUX_COEFFICIENT;
One line.
> > + dev_dbg(&client->dev, "Counts Per Lux: %d\n", counts_per_lux);
> > + /* Calculate lux value */
> > + lux = ((als_ch0 - als_ch1) *
> > + (1000 - ((als_ch1 * 1000) / als_ch0))) / counts_per_lux;
> > + dev_dbg(&client->dev, "Raw lux calculation: %d\n", lux);
> > +
> > + /* Divide by 1000 to get real lux value before scaling */
> > + *val = lux / 1000;
Doing this before the following one makes precision drop. Or not?
> > + /* Get the decimal part of lux reading */
> > + *val2 = ((lux - (*val * 1000)) * 1000);
> > +
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + return ret;
>
> See above for why: I'd return 0 here
>
> > +}
...
> > + als_lower_l = (als_settings.als_lower_thresh & 0x00FF);
>
> Given you are writing these into a byte field, probably better to express those
> masks as 0xFF.
u8 type may never be bigger than 255. Masks like that are redundant.
> > + als_lower_h = ((als_settings.als_lower_thresh >> 8) & 0x00FF);
> > + als_upper_l = (als_settings.als_upper_thresh & 0x00FF);
> > + als_upper_h = ((als_settings.als_upper_thresh >> 8) & 0x00FF);
Ditto.
...
> > +static int tsl2591_write_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int val, int val2, long mask)
> > +{
> > + struct tsl2591_chip *chip = iio_priv(indio_dev);
> > +
> > + u8 gain;
> > + u32 int_time;
> > + int ret;
No need for power management?
> > + mutex_lock(&chip->als_mutex);
> > + mutex_unlock(&chip->als_mutex);
> > + return ret;
> > +}
...
> > +static int tsl2591_read_event_value(struct iio_dev *indio_dev,
> > + const struct iio_chan_spec *chan,
> > + enum iio_event_type type,
> > + enum iio_event_direction dir,
> > + enum iio_event_info info, int *val,
> > + int *val2)
Ditto.
...
> > +static int __maybe_unused tsl2591_resume(struct device *dev)
> > +{
> > + struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > + struct tsl2591_chip *chip = iio_priv(indio_dev);
> > + int ret;
> > + int power_state;
> > +
> > + if (chip->events_enabled)
> > + power_state = TSL2591_PWR_ON |
> > + TSL2591_ENABLE_ALS_INT |
> > + TSL2591_ENABLE_ALS;
At least the last two can be on one line.
> > + else
> > + power_state = TSL2591_PWR_ON | TSL2591_ENABLE_ALS;
> > +
> > + mutex_lock(&chip->als_mutex);
> > + ret = tsl2591_set_power_state(chip, power_state);
> > + mutex_unlock(&chip->als_mutex);
> > +
> > + return ret;
> > +}
...
> > +static const struct dev_pm_ops tsl2591_pm_ops = {
> > + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> > + pm_runtime_force_resume)
One line?
> > + SET_RUNTIME_PM_OPS(tsl2591_suspend, tsl2591_resume, NULL)
> > +};
...
> > +static irqreturn_t tsl2591_event_handler(int irq, void *private)
> > +{
> > + /* Clear ALS irq */
> > + ret = i2c_smbus_write_byte(client, TSL2591_CMD_SF_CALS_NPI);
> > + if (ret < 0)
> > + dev_err(&client->dev, "Failed to clear als irq\n");
In the IRQ handler? Hmm... It potentially floods the logs.
> > + return IRQ_HANDLED;
> > +}
...
> > +static const struct of_device_id tsl2591_of_match[] = {
> > + { .compatible = "amstaos,tsl2591"},
> > + {},
Comma is not needed on the terminator line.
> > +};
--
With Best Regards,
Andy Shevchenko
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