From: Johan Hovold <johan@kernel.org>
To: Tomasz Duszynski <tduszyns@gmail.com>
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org
Subject: Re: [PATCH 1/3] iio: chemical: add support for Plantower PMS7003 sensor
Date: Mon, 7 Jan 2019 16:35:42 +0100 [thread overview]
Message-ID: <20190107153542.GD14782@localhost> (raw)
In-Reply-To: <20190106171614.12615-2-tduszyns@gmail.com>
On Sun, Jan 06, 2019 at 06:16:12PM +0100, Tomasz Duszynski wrote:
> Add support for Plantower PMS7003 particulate matter sensor.
>
> Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> +static int pms7003_do_cmd(struct pms7003_state *state, u8 cmd)
> +{
> + /*
> + * commands have following format:
> + *
> + * +------+------+-----+------+-----+-----------+-----------+
> + * | 0x42 | 0x4d | cmd | 0x00 | arg | cksum msb | cksum lsb |
> + * +------+------+-----+------+-----+-----------+-----------+
> + */
> + u8 tmp[PMS7003_CMD_LENGTH] = { PMS7003_MAGIC_MSB, PMS7003_MAGIC_LSB };
> + int ret, n = 2;
> + u16 checksum;
> +
> + switch (cmd) {
> + case CMD_WAKEUP:
> + tmp[n++] = 0xe4;
> + tmp[n++] = 0x00;
> + tmp[n++] = 0x01;
> + break;
> + case CMD_ENTER_PASSIVE_MODE:
> + tmp[n++] = 0xe1;
> + tmp[n++] = 0x00;
> + tmp[n++] = 0x00;
> + break;
> + case CMD_READ_PASSIVE:
> + tmp[n++] = 0xe2;
> + tmp[n++] = 0x00;
> + tmp[n++] = 0x00;
> + break;
> + case CMD_SLEEP:
> + tmp[n++] = 0xe4;
> + tmp[n++] = 0x00;
> + tmp[n++] = 0x00;
> + break;
> + }
> +
> + checksum = pms7003_calc_checksum(tmp, n);
> + put_unaligned_be16(checksum, tmp + n);
> + n += PMS7003_CHECKSUM_LENGTH;
> +
> + ret = serdev_device_write(state->serdev, tmp, n, PMS7003_TIMEOUT);
> + if (ret)
> + return ret;
Beginning with 5.0, serdev_device_write() returns the number of bytes
written before timeout (or being interrupted) so you need to check
against < n here.
Johan
next prev parent reply other threads:[~2019-01-07 15:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-06 17:16 [PATCH 0/3] add support for PMS7003 PM sensor Tomasz Duszynski
2019-01-06 17:16 ` [PATCH 1/3] iio: chemical: add support for Plantower PMS7003 sensor Tomasz Duszynski
2019-01-07 15:35 ` Johan Hovold [this message]
2019-01-08 19:07 ` Tomasz Duszynski
2019-01-12 17:48 ` Jonathan Cameron
2019-01-23 21:08 ` Tomasz Duszynski
2019-01-06 17:16 ` [PATCH 2/3] dt-bindings: add Plantower to the vendor prefixes Tomasz Duszynski
2019-01-11 22:12 ` Rob Herring
2019-01-06 17:16 ` [PATCH 3/3] dt-bindings: iio: chemical: pms7003: add device tree support Tomasz Duszynski
2019-01-11 22:15 ` Rob Herring
2019-01-27 13:45 ` Tomasz Duszynski
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