From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Dongchun Zhu <dongchun.zhu@mediatek.com>
Cc: linus.walleij@linaro.org, bgolaszewski@baylibre.com,
mchehab@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com,
sakari.ailus@linux.intel.com, drinkcat@chromium.org,
tfiga@chromium.org, matthias.bgg@gmail.com, bingbu.cao@intel.com,
srv_heupstream@mediatek.com, linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, sj.huang@mediatek.com,
linux-media@vger.kernel.org, devicetree@vger.kernel.org,
louis.kuo@mediatek.com, shengnan.wang@mediatek.com
Subject: Re: [V7, 2/2] media: i2c: dw9768: Add DW9768 VCM driver
Date: Fri, 5 Jun 2020 15:46:43 +0300 [thread overview]
Message-ID: <20200605124643.GG2428291@smile.fi.intel.com> (raw)
In-Reply-To: <20200605105412.18813-3-dongchun.zhu@mediatek.com>
On Fri, Jun 05, 2020 at 06:54:12PM +0800, Dongchun Zhu wrote:
> Add a V4L2 sub-device driver for DW9768 voice coil motor, providing
> control to set the desired focus via IIC serial interface.
...
> +config VIDEO_DW9768
> + tristate "DW9768 lens voice coil support"
> + depends on I2C && VIDEO_V4L2
No compile test?
> + depends on PM
This is very strange dependency for ordinary driver.
> + select MEDIA_CONTROLLER
> + select VIDEO_V4L2_SUBDEV_API
> + select V4L2_FWNODE
...
> +/*
> + * DW9768 requires waiting time (delay time) of t_OPR after power-up,
> + * or in the case of PD reset taking place.
> + */
> +#define DW9768_T_OPR_US 1000
> +#define DW9768_Tvib_MS_BASE10 (64 - 1)
> +#define DW9768_AAC_MODE_DEFAULT 2
> +#define DW9768_AAC_TIME_DEFAULT 0x20
Hex? Why not decimal?
> +#define DW9768_CLOCK_PRE_SCALE_DEFAULT 1
...
> +static int dw9768_mod_reg(struct dw9768 *dw9768, u8 reg, u8 mask, u8 val)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
> + int ret;
> +
> + ret = i2c_smbus_read_byte_data(client, reg);
> + if (ret < 0)
> + return ret;
> +
> + val = ((unsigned char)ret & ~mask) | (val & mask);
This cast is weird.
> +
> + return i2c_smbus_write_byte_data(client, reg, val);
> +}
...
> + dev_err(&client->dev, "%s I2C failure: %d",
> + __func__, ret);
One line?
...
> +static int dw9768_release(struct dw9768 *dw9768)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&dw9768->sd);
> + u32 move_delay_us = dw9768_cal_move_delay(dw9768->aac_mode,
> + dw9768->clock_presc,
> + dw9768->aac_timing) / 100;
> + int ret, val;
> +
> + val = round_down(dw9768->focus->val, DW9768_MOVE_STEPS);
> + for ( ; val >= 0; val -= DW9768_MOVE_STEPS) {
> + ret = dw9768_set_dac(dw9768, val);
> + if (ret) {
> + dev_err(&client->dev, "I2C write fail: %d", ret);
> + return ret;
> + }
> + usleep_range(move_delay_us, move_delay_us + 1000);
> + }
It will look more naturally in the multiplier kind of value.
unsigned int steps = DIV_ROUND_UP(...);
while (steps--) {
...(..., steps * ..._MOVE_STEPS);
...
}
but double check arithmetics.
> + return 0;
> +}
Also it seems we need to have writex_poll_timeout() implementation (see
iopoll.h).
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-06-05 12:46 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-05 10:54 [V7, 0/2] media: i2c: Add support for DW9768 VCM driver Dongchun Zhu
2020-06-05 10:54 ` [V7, 1/2] media: dt-bindings: media: i2c: Document DW9768 bindings Dongchun Zhu
2020-06-09 19:47 ` Rob Herring
2020-06-05 10:54 ` [V7, 2/2] media: i2c: dw9768: Add DW9768 VCM driver Dongchun Zhu
2020-06-05 12:14 ` Sakari Ailus
2020-06-05 13:02 ` Tomasz Figa
2020-06-05 13:37 ` Sakari Ailus
2020-06-06 6:24 ` Dongchun Zhu
2020-06-05 12:46 ` Andy Shevchenko [this message]
2020-06-05 13:10 ` Tomasz Figa
2020-06-06 6:19 ` Dongchun Zhu
2020-06-08 13:27 ` Andy Shevchenko
2020-06-09 3:45 ` Dongchun Zhu
2020-06-09 11:14 ` Andy Shevchenko
2020-06-10 12:58 ` Sakari Ailus
2020-06-05 13:44 ` Tomasz Figa
2020-06-06 6:42 ` Dongchun Zhu
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