Hi,
On Tue, 2013-09-10 at 08:46 -0500, Josh Cartwright wrote:
> Hey Ivan-
>
> Some nits below.
>
> On Thu, Aug 29, 2013 at 04:27:53PM +0300, Ivan T. Ivanov wrote:
> > From: "Ivan T. Ivanov" <iivanov@xxxxxxxxxx>
> >
> > This bus driver supports the QUP i2c hardware controller in the Qualcomm
> > MSM SOCs. The Qualcomm Universal Peripheral Engine (QUP) is a general
> > purpose data path engine with input/output FIFOs and an embedded i2c
> > mini-core. The driver supports FIFO mode (for low bandwidth applications)
>
> Rogue tab in your commit message.
Will fix.
>
> > and block mode (interrupt generated for each block-size data transfer).
> > The driver currently does not support DMA transfers.
> >
> > Shamelessly based on codeaurora version of the driver.
> >
> > This controller could be found in the following chip-sets:
> > msm9625, msm8974, msm8610, msm8226, mpq8092.
>
> This may be good to include in the Kconfig help text.
Will do.
>
> > Signed-off-by: Ivan T. Ivanov <iivanov@xxxxxxxxxx>
> > ---
> > drivers/i2c/busses/Kconfig | 10 +
> > drivers/i2c/busses/Makefile | 1 +
> > drivers/i2c/busses/i2c-qup.c | 909 ++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 920 insertions(+)
> > create mode 100644 drivers/i2c/busses/i2c-qup.c
> >
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index fcdd321..c76ddd4 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -777,6 +777,16 @@ config I2C_RCAR
> > This driver can also be built as a module. If so, the module
> > will be called i2c-rcar.
> >
> > +config I2C_QUP
> > + tristate "Qualcomm QUP based I2C controller"
> > + depends on ARCH_MSM
> > + help
> > + If you say yes to this option, support will be included for the
> > + built-in I2C interface on the MSM family processors.
> > +
> > + This driver can also be built as a module. If so, the module
> > + will be called i2c-qup.
> > +
> > comment "External I2C/SMBus adapter drivers"
> >
> > config I2C_DIOLAN_U2C
> > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> > index d00997f..77127df 100644
> > --- a/drivers/i2c/busses/Makefile
> > +++ b/drivers/i2c/busses/Makefile
> > @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
> > obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
> > obj-$(CONFIG_I2C_XLR) += i2c-xlr.o
> > obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o
> > +obj-$(CONFIG_I2C_QUP) += i2c-qup.o
> >
> > # External I2C/SMBus adapter drivers
> > obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o
> > diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> > new file mode 100644
> > index 0000000..3b5ef91
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-qup.c
> [..]
> > +
> > +static int qup_i2c_change_state(struct qup_i2c_dev *qup, u32 state)
> > +{
> > + if (qup_i2c_poll_state(qup, 0, true) != 0)
> > + return -EIO;
> > +
> > + writel(state, qup->base + QUP_STATE);
> > +
> > + if (qup_i2c_poll_state(qup, state, false) != 0)
> > + return -EIO;
> > + return 0;
> > +}
> > +
> > +static void qup_i2c_enable(struct qup_i2c_dev *qup, bool state)
>
> Bit of a confusing name, especially when qup_i2c_enable(qup, false) is
> used. I'd suggest qup_i2c_set_state or qup_i2c_set_enabled.
Indeed. I prefer qup_i2c_set_enabled.
>
> > +{
> > + u32 config;
> > +
> > + if (state) {
> > + clk_prepare_enable(qup->clk);
> > + clk_prepare_enable(qup->pclk);
> > + } else {
> > + qup_i2c_change_state(qup, QUP_RESET_STATE);
> > + clk_disable_unprepare(qup->clk);
> > + config = readl(qup->base + QUP_CONFIG);
> > + config |= QUP_CLOCK_AUTO_GATE;
> > + writel(config, qup->base + QUP_CONFIG);
> > + clk_disable_unprepare(qup->pclk);
> > + }
> > +}
> [..]
> > +static int qup_i2c_probe(struct platform_device *pdev)
> > +{
> [..]
> > +
> > + ret = devm_request_irq(qup->dev, qup->irq, qup_i2c_interrupt,
> > + IRQF_TRIGGER_HIGH, "i2c_qup", qup);
> > + if (ret) {
> > + dev_err(qup->dev, "Request %d IRQ failed\n", qup->irq);
> > + return ret;
> > + }
> > +
> > + disable_irq(qup->irq);
>
> How is this not racy, in the case where a pending interrupt is left from
> the bootloader (which seems to be possible based on the comments below)?
Yes it looks weird. Interrupt handler will check and exit if there
is no message for transfer. I am looking for better way to handle this.
Thanks,
Ivan
>
> > +
> > + init_completion(&qup->xfer);
> > +
> > + ret = clk_set_rate(qup->clk, qup->src_clk_freq);
> > + if (ret)
> > + dev_info(qup->dev, "Fail to set core clk, %dHz:%d\n",
> > + qup->src_clk_freq, ret);
> > +
> > + qup_i2c_enable(qup, true);
> > +
> > + /*
> > + * If bootloaders leave a pending interrupt on certain QUP's,
> > + * then we reset the core before registering for interrupts.
> > + */
> [..]
>
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
