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Message-ID: <20140115164604.GI14405@codeaurora.org>
Date: Wed, 15 Jan 2014 08:46:04 -0800
From: Stephen Boyd <sboyd@...eaurora.org>
To: Bjorn Andersson <bjorn.andersson@...ymobile.com>
Cc: Rob Herring <rob.herring@...xeda.com>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Rob Landley <rob@...dley.net>,
Wolfram Sang <wsa@...-dreams.de>,
Grant Likely <grant.likely@...aro.org>,
"Ivan T. Ivanov" <iivanov@...sol.com>,
Jean Delvare <khali@...ux-fr.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
James Ralston <james.d.ralston@...el.com>,
Bill Brown <bill.e.brown@...el.com>,
Matt Porter <matt.porter@...aro.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-i2c@...r.kernel.org,
linux-arm-msm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/2] i2c: New bus driver for the QUP I2C controller
On 01/13, Bjorn Andersson wrote:
> +/*
> + * QUP driver for Qualcomm MSM platforms
> + *
> + */
This comment seems redundant, we know what file we're looking at.
> +
> +struct qup_i2c_dev {
> + struct device *dev;
> + void __iomem *base;
> + struct pinctrl *pctrl;
This is unused.
> + int irq;
> + struct clk *clk;
> + struct clk *pclk;
> + struct i2c_adapter adap;
> +
> + int clk_freq;
This is only ever used in probe, so why do we need to store it
away?
> + int clk_ctl;
> + int one_bit_t;
> + int out_fifo_sz;
> + int in_fifo_sz;
> + int out_blk_sz;
> + int in_blk_sz;
> + unsigned long xfer_time;
> + unsigned long wait_idle;
> +
> + struct i2c_msg *msg;
> + /* Current possion in user message buffer */
s/possion/position/?
> + int pos;
> + /* Keep number of bytes left to be transmitted */
> + int cnt;
> + /* I2C protocol errors */
> + u32 bus_err;
> + /* QUP core errors */
> + u32 qup_err;
> + /*
> + * maximum bytes that could be send (per iterration). could be
s/iterration/iteration/?
> + * equal of fifo size or block size (in block mode)
> + */
> + int chunk_sz;
> + struct completion xfer;
> +};
> +
> +static irqreturn_t qup_i2c_interrupt(int irq, void *dev)
> +{
> + struct qup_i2c_dev *qup = dev;
> + u32 bus_err;
> + u32 qup_err;
> + u32 opflags;
> +
[...]
> +
> + if (opflags & QUP_OUT_SVC_FLAG)
> + writel(QUP_OUT_SVC_FLAG, qup->base + QUP_OPERATIONAL);
> +
> + if (!(qup->msg->flags == I2C_M_RD))
Should this be?
if (!(qup->msg->flags & I2C_M_RD))
Otherwise it should be
if (qup->msg->flags != I2C_M_RD)
> + return IRQ_HANDLED;
> +
> + if ((opflags & QUP_MX_INPUT_DONE) || (opflags & QUP_IN_SVC_FLAG))
> + writel(QUP_IN_SVC_FLAG, qup->base + QUP_OPERATIONAL);
> +
> +done:
> + qup->qup_err = qup_err;
> + qup->bus_err = bus_err;
> + complete(&qup->xfer);
> + return IRQ_HANDLED;
> +}
> +
> +static int
> +qup_i2c_poll_state(struct qup_i2c_dev *qup, u32 req_state, bool only_valid)
> +{
> + int retries = 0;
> + u32 state;
> +
> + do {
> + state = readl(qup->base + QUP_STATE);
> +
> + /*
> + * If only valid bit needs to be checked, requested state is
> + * 'don't care'
> + */
It looks like req_state == 0 means only_valid == true. Can we
drop the only_valid argument to this function?
> + if (state & QUP_STATE_VALID) {
> + if (only_valid)
> + return 0;
> + if ((req_state & QUP_I2C_MAST_GEN)
> + && (state & QUP_I2C_MAST_GEN))
> + return 0;
> + if ((state & QUP_STATE_MASK) == req_state)
> + return 0;
> + }
> +
> + if (retries++ == 1000)
> + udelay(100);
> +
> + } while (retries != 2000);
Please makes #defines for 1000 and 2000.
> +
> + return -ETIMEDOUT;
> +}
> +
[...]
> +static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
> +{
> + u32 addr = msg->addr << 1;
> + u32 val, qup_tag;
> + int idx, entries;
> +
> + if (qup->pos == 0) {
> + val = QUP_OUT_START | addr;
> + } else {
> + /*
> + * Avoid setup time issue by adding 1 NOP when number of bytes
> + * are more than FIFO/BLOCK size. setup time issue can't appear
> + * otherwise since next byte to be written will always be ready
> + */
> + val = (QUP_OUT_NOP | 1);
> + }
> +
> + entries = qup->cnt + 1;
> +
> + if (entries > qup->chunk_sz)
> + entries = qup->chunk_sz;
> +
> + qup_tag = QUP_OUT_DATA;
> +
> + /* Reserve one entry for STOP */
> + for (idx = 1; idx < (entries - 1); idx++, qup->pos++) {
Unnecessary () here around entries.
> +
> + if (idx & 1) {
> + val |= (qup_tag | msg->buf[qup->pos]) << QUP_MSW_SHIFT;
> + writel(val, qup->base + QUP_OUT_FIFO_BASE);
> + } else {
> + val = qup_tag | msg->buf[qup->pos];
> + }
[...]
> +
> +#ifdef CONFIG_PM
This ifdef is probably wrong considering that you can disable
CONFIG_PM_RUNTIME without disabling CONFIG_PM and then these
runtime PM functions would be unused.
> +static int qup_i2c_pm_suspend_runtime(struct device *device)
> +{
> + struct qup_i2c_dev *qup = dev_get_drvdata(device);
> +
> + dev_dbg(device, "pm_runtime: suspending...\n");
> + qup_i2c_disable_clocks(qup);
> + return 0;
> +}
> +
> +static int qup_i2c_pm_resume_runtime(struct device *device)
> +{
> + struct qup_i2c_dev *qup = dev_get_drvdata(device);
> +
> + dev_dbg(device, "pm_runtime: resuming...\n");
> + qup_i2c_enable_clocks(qup);
> + return 0;
> +}
> +
> +static int qup_i2c_suspend(struct device *device)
> +{
> + dev_dbg(device, "system suspend");
> + qup_i2c_pm_suspend_runtime(device);
> + return 0;
> +}
> +
> +static int qup_i2c_resume(struct device *device)
> +{
> + dev_dbg(device, "system resume");
> + qup_i2c_pm_resume_runtime(device);
> + pm_runtime_mark_last_busy(device);
> + pm_request_autosuspend(device);
> + return 0;
> +}
> +#endif /* CONFIG_PM */
> +
> +static const struct dev_pm_ops qup_i2c_qup_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(
> + qup_i2c_suspend,
> + qup_i2c_resume)
> + SET_RUNTIME_PM_OPS(
> + qup_i2c_pm_suspend_runtime,
> + qup_i2c_pm_resume_runtime,
> + NULL)
> +};
> +
> +static struct of_device_id qup_i2c_dt_match[] = {
const?
> + {.compatible = "qcom,i2c-qup"},
> + {}
> +};
MODULE_DEVICE_TABLE(of, qup_i2c_dt_match)?
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