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Date: Wed, 18 Aug 2010 17:42:37 +0400
From: Anton Vorontsov <cbouatmailru@...il.com>
To: "Krogerus Heikki (EXT-Teleca/Helsinki)"
<ext-heikki.krogerus@...ia.com>
Cc: linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
dwmw2@...radead.org, felipe.balbi@...ia.com,
ameya.palande@...ia.com, markus.lehtonen@...ia.com,
roger.quadros@...ia.com
Subject: Re: [PATCH] power_supply: add isp1704 charger detection driver
On Wed, Aug 18, 2010 at 04:01:05PM +0300, Krogerus Heikki (EXT-Teleca/Helsinki) wrote:
> From: Heikki Krogerus <ext-heikki.krogerus@...ia.com>
>
> NXP ISP1704 is Battery Charging Specification 1.0 compliant USB
> transceiver. This adds a power supply driver for ISP1704 and
> ISP1707 USB transceivers.
>
> Signed-off-by: Heikki Krogerus <ext-heikki.krogerus@...ia.com>
> ---
I like this driver (very). A few, mostly cosmetic comments down
below.
[...]
> +config CHARGER_ISP1704
> + tristate "ISP1704 USB Charger Detection"
> + select NOP_USB_XCEIV if ! MACH_NOKIA_RX51
> + help
"! MACH_NOKIA_RX51" looks wrong here. You probably don't actually
need this if you fix platform device registration issue (see the
very bottom of this email).
[...]
> +/*
> + * ISP1704 detects PS/2 adapters as charger. To make sure the detected charger
> + * is actually a dedicated charger, the following steps need to be taken.
> + */
> +static inline int isp1704_charger_verify(struct isp1704_charger *isp)
> +{
> + u8 r, ret = 0;
Please put variable declarations on separate lines, plus,
'ret' should probably be int, i.e.
int ret;
u8 r;
> +
> + /* Reset the transceiver */
> + r = otg_io_read(isp->otg, ULPI_FUNC_CTRL);
> + r |= ULPI_FUNC_CTRL_RESET;
> + otg_io_write(isp->otg, ULPI_FUNC_CTRL, r);
> + usleep_range(1000, 2000);
> +
> + /* Set normal mode */
> + r &= ~(ULPI_FUNC_CTRL_RESET | ULPI_FUNC_CTRL_OPMODE_MASK);
> + otg_io_write(isp->otg, ULPI_FUNC_CTRL, r);
> +
> + /* Clear the DP and DM pull-down bits */
> + r = ULPI_OTG_CTRL_DP_PULLDOWN | ULPI_OTG_CTRL_DM_PULLDOWN;
> + otg_io_write(isp->otg, ULPI_CLR(ULPI_OTG_CTRL), r);
> +
> + /* Enable strong pull-up on DP (1.5K) and reset */
> + r = ULPI_FUNC_CTRL_TERMSELECT | ULPI_FUNC_CTRL_RESET;
> + otg_io_write(isp->otg, ULPI_SET(ULPI_FUNC_CTRL), r);
> + usleep_range(1000, 2000);
> +
> + /* Read the line state */
> + if (otg_io_read(isp->otg, ULPI_DEBUG)) {
> + /* Is it a charger or PS/2 connection */
> +
> + /* Enable weak pull-up resistor on DP */
> + otg_io_write(isp->otg, ULPI_SET(ISP1704_PWR_CTRL),
> + ISP1704_PWR_CTRL_DP_WKPU_EN);
> +
> + /* Disable strong pull-up on DP (1.5K) */
> + otg_io_write(isp->otg, ULPI_CLR(ULPI_FUNC_CTRL),
> + ULPI_FUNC_CTRL_TERMSELECT);
> +
> + /* Enable weak pull-down resistor on DM */
> + otg_io_write(isp->otg, ULPI_SET(ULPI_OTG_CTRL),
> + ULPI_OTG_CTRL_DM_PULLDOWN);
> +
> + /* It's a charger if the line states are clear */
> + if (!(otg_io_read(isp->otg, ULPI_DEBUG)))
> + ret = 1;
> +
> + /* Disable weak pull-up resistor on DP */
> + otg_io_write(isp->otg, ULPI_CLR(ISP1704_PWR_CTRL),
> + ISP1704_PWR_CTRL_DP_WKPU_EN);
> + } else {
> + ret = 1;
> +
> + /* Disable strong pull-up on DP (1.5K) */
> + otg_io_write(isp->otg, ULPI_CLR(ULPI_FUNC_CTRL),
> + ULPI_FUNC_CTRL_TERMSELECT);
> + }
How about
if (!otg_io_read(isp->otg, ULPI_DEBUG)) {
/* Disable strong pull-up on DP (1.5K) */
otg_io_write(isp->otg, ULPI_CLR(ULPI_FUNC_CTRL),
ULPI_FUNC_CTRL_TERMSELECT);
return 1;
}
<the rest>
Saves indentation level.
> + return ret;
> +}
> +
> +static inline int isp1704_charger_detect(struct isp1704_charger *isp)
> +{
> + unsigned long timeout;
> + u8 r;
> + int vdat;
> +
> + /* set SW control bit in PWR_CTRL register */
> + otg_io_write(isp->otg, ISP1704_PWR_CTRL,
> + ISP1704_PWR_CTRL_SWCTRL);
> +
> + /* enable manual charger detection */
> + r = (ISP1704_PWR_CTRL_SWCTRL | ISP1704_PWR_CTRL_DPVSRC_EN);
> + otg_io_write(isp->otg, ULPI_SET(ISP1704_PWR_CTRL), r);
> + usleep_range(1000, 2000);
> +
> + timeout = jiffies + msecs_to_jiffies(300);
> + while (!time_after(jiffies, timeout)) {
I guess it is possible that vdat might become uninitialized
if the code never hits the loop. The time between
timeout = jiffies + msecs_to_jiffies(300);
and
while (!time_after(jiffies, timeout)) {
is undefined.
> + /* Check if there is a charger */
> + vdat = !!(otg_io_read(isp->otg, ISP1704_PWR_CTRL)
> + & ISP1704_PWR_CTRL_VDAT_DET);
Technically, there is no need for "!!".
> + if (vdat)
> + break;
> + }
> + return vdat;
> +}
> +
> +static void isp1704_charger_work(struct work_struct *data)
> +{
> + struct isp1704_charger *isp =
> + container_of(data, struct isp1704_charger, work);
> +
> + /* FIXME Only supporting dedicated chargers even though isp1704 can
> + * detect HUB and HOST chargers. If the device has already been
> + * enumerated, the detection will break the connection.
> + */
> + if (isp->otg->state != OTG_STATE_B_IDLE)
> + return;
> +
> + /* disable data pullups */
> + if (isp->otg->gadget)
> + usb_gadget_disconnect(isp->otg->gadget);
> +
> + /* detect charger */
shouldn't be there 'isp->present = 0;'?..
> + if (isp1704_charger_detect(isp))
> + isp->present = isp1704_charger_verify(isp);
i.e. it's kinda weird to see conditional isp->present update...
> +
> + /* enable data pullups */
> + if (isp->otg->gadget)
> + usb_gadget_connect(isp->otg->gadget);
> +
> + if (isp->present)
...and then unconditional checking of isp->present.
I guess the code is OK, and somewhere else the logic handles
this... but still an odd-looking function.
> + power_supply_changed(&isp->psy);
> +}
> +
> +static int isp1707_notifier_call(struct notifier_block *nb,
> + unsigned long event, void *unused)
> +{
> + struct isp1704_charger *isp =
> + container_of(nb, struct isp1704_charger, nb);
> +
> + switch (event) {
> + case USB_EVENT_VBUS:
> + schedule_work(&isp->work);
> + break;
> + case USB_EVENT_NONE:
> + isp->present = 0;
Probably this makes the code above work. But why don't we
call schedule_work(&isp->work)?
[...]
> +static inline int isp1704_test_ulpi(struct isp1704_charger *isp)
> +{
> + int vendor, product, i;
int vendor;
int product;
int i;
> + int ret = -ENODEV;
> +
> + /* Test ULPI interface */
> + ret = otg_io_write(isp->otg, ULPI_SCRATCH, 0xaa);
> + if (ret < 0)
> + return ret;
By adding empty line here you'll make the code prettier.
> + ret = otg_io_read(isp->otg, ULPI_SCRATCH);
> + if (ret < 0)
> + return ret;
Ditto.
> + if (ret != 0xaa)
> + return -ENODEV;
Ditto.
> + /* Verify the product and vendor id matches */
> + vendor = otg_io_read(isp->otg, ULPI_VENDOR_ID_LOW);
> + vendor |= otg_io_read(isp->otg, ULPI_VENDOR_ID_HIGH) << 8;
> + if (vendor != NXP_VENDOR_ID)
> + return -ENODEV;
Ditto.
> + for (i = 0; i < ARRAY_SIZE(isp170x_id); i++) {
> + product = otg_io_read(isp->otg, ULPI_PRODUCT_ID_LOW);
> + product |= otg_io_read(isp->otg, ULPI_PRODUCT_ID_HIGH) << 8;
> + if (product == isp170x_id[i]) {
> + sprintf(isp->model, "isp%x", product);
> + return product;
> + }
> + }
> +
> + dev_err(isp->dev, "product id %x not matching known ids", product);
> +
> + return -ENODEV;
> +}
> +
> +static int __devinit isp1704_charger_probe(struct platform_device *pdev)
> +{
> + struct isp1704_charger *isp;
> + int ret = -ENODEV;
> +
> + isp = kzalloc(sizeof *isp, GFP_KERNEL);
> + if (!isp)
> + return -ENOMEM;
> +
> + isp->otg = otg_get_transceiver();
> + if (!isp->otg) {
> + kfree(isp);
> + return ret;
goto failX instead?
> + }
> +
> + ret = isp1704_test_ulpi(isp);
> + if (ret < 0)
> + goto fail;
> +
> + isp->dev = &pdev->dev;
> + platform_set_drvdata(pdev, isp);
> +
> + isp->psy.name = "isp1704";
> + isp->psy.type = POWER_SUPPLY_TYPE_USB;
> + isp->psy.properties = power_props;
> + isp->psy.num_properties = ARRAY_SIZE(power_props);
> + isp->psy.get_property = isp1704_charger_get_property;
> +
> + ret = power_supply_register(isp->dev, &isp->psy);
> + if (ret)
> + goto fail;
> +
> + /* REVISIT: using work in order to allow the otg notifications to be
> + * made atomically in the future.
> + */
> + INIT_WORK(&isp->work, isp1704_charger_work);
> +
> + isp->nb.notifier_call = isp1707_notifier_call;
Add an empty line here?
> + ret = otg_register_notifier(isp->otg, &isp->nb);
> + if (ret)
> + goto fail2;
> +
> + dev_info(isp->dev, "registered with product id %s\n", isp->model);
> +
> + return 0;
> +fail2:
> + power_supply_unregister(&isp->psy);
> +fail:
> + otg_put_transceiver(isp->otg);
> + kfree(isp);
> +
> + dev_err(&pdev->dev, "failed to register isp1704 with error %d\n", ret);
> +
> + return ret;
> +}
[...]
> +static int __init isp1704_charger_init(void)
> +{
> + int ret = 0;
> +
> + ret = platform_driver_register(&isp1704_charger_driver);
> + if (ret)
> + return ret;
> +
> + isp1704_device = platform_device_register_simple("isp1704_charger",
> + 0, NULL, 0);
This is wrong. Please move this into either isp1704 generic
or usb driver (if any), or platform (board) code.
That way you also won't need "! MACH_NOKIA_RX51" in the Kconfig.
Thanks!
--
Anton Vorontsov
email: cbouatmailru@...il.com
irc://irc.freenode.net/bd2
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