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Message-ID: <CAHp75Ve+J+ECRpsCCoV_87nHH+AALQpgrygiy0qSOFMK22yABw@mail.gmail.com>
Date: Tue, 7 Feb 2017 12:47:20 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Baoyou Xie <baoyou.xie@...aro.org>
Cc: jun.nie@...aro.org, Wolfram Sang <wsa@...-dreams.de>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
linux-i2c@...r.kernel.org, devicetree <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 3/3] i2c: zx2967: add i2c controller driver for ZTE's
zx2967 family
On Mon, Feb 6, 2017 at 5:26 AM, Baoyou Xie <baoyou.xie@...aro.org> wrote:
> This patch adds i2c controller driver for ZTE's zx2967 family.
> +#define I2C_STOP 0
> +#define I2C_MASTER BIT(0)
> +#define I2C_ADDR_MODE_TEN BIT(1)
> +#define I2C_IRQ_MSK_ENABLE BIT(3)
> +#define I2C_RW_READ BIT(4)
> +#define I2C_CMB_RW_EN BIT(5)
> +#define I2C_START BIT(6)
> +#define I2C_ADDR_MODE_TEN BIT(1)
I'm not sure you have to repeat this.
> +#define I2C_WFIFO_RESET BIT(7)
> +#define I2C_RFIFO_RESET BIT(7)
Hmm... Are they applied to the same register?
> +struct zx2967_i2c_info {
> + spinlock_t lock;
> + struct device *dev;
> + struct i2c_adapter adap;
I'm pretty sure you may access *dev from adap. Or they are different devices?
> + struct clk *clk;
> + struct completion complete;
> + u32 clk_freq;
> + void __iomem *reg_base;
> + size_t residue;
> + int irq;
> + int msg_rd;
> + u8 *buf;
> + u8 access_cnt;
> + bool is_suspended;
> +};
> +static void zx2967_i2c_flush_fifos(struct zx2967_i2c_info *zx_i2c)
> +{
> + u32 val;
> + u32 offset;
Reversed tree?
> +
> + if (zx_i2c->msg_rd) {
> + offset = REG_RDCONF;
> + val = I2C_RFIFO_RESET;
> + } else {
> + offset = REG_WRCONF;
> + val = I2C_WFIFO_RESET;
> + }
> +
> + val |= zx2967_i2c_readl(zx_i2c, offset);
> + zx2967_i2c_writel(zx_i2c, val, offset);
> +}
> + zx2967_i2c_readsb(zx_i2c, val, REG_DATA, size);
> + for (i = 0; i < size; i++) {
> + *(zx_i2c->buf++) = val[i];
Do you need parens? I guess *p++ = x; is quite understandable pattern.
> + zx_i2c->residue--;
> + if (zx_i2c->residue <= 0)
> + break;
> + }
> +
> + barrier();
> +
> + return 0;
> +}
> +static int zx2967_i2c_fill_tx_fifo(struct zx2967_i2c_info *zx_i2c)
> +{
> + u8 *buf = zx_i2c->buf;
> + size_t residue = zx_i2c->residue;
Reversed tree?
> +
> + if (residue == 0) {
> + dev_err(zx_i2c->dev, "residue is %d\n", (int)residue);
> + return -EINVAL;
> + }
> +static void zx2967_enable_tenbit(struct zx2967_i2c_info *zx_i2c, __u16 addr)
> +{
> + u16 val = (addr >> 7) & 0x7;
Magic values.
> + if (val > 0) {
It can't be negative ->
if (val) {
> + zx2967_i2c_writel(zx_i2c, val, REG_DEVADDR_H);
> + val = (zx2967_i2c_readl(zx_i2c, REG_CMD)) | I2C_ADDR_MODE_TEN;
> + zx2967_i2c_writel(zx_i2c, val, REG_CMD);
> + }
> +}
> +static int zx2967_i2c_xfer(struct i2c_adapter *adap,
> + struct i2c_msg *msgs, int num)
> +{
> + struct zx2967_i2c_info *zx_i2c = i2c_get_adapdata(adap);
> + int ret;
> + int i;
> +
> + if (zx_i2c->is_suspended)
> + return -EBUSY;
> +
> + zx2967_i2c_writel(zx_i2c, (msgs->addr & 0x7f), REG_DEVADDR_L);
> + zx2967_i2c_writel(zx_i2c, (msgs->addr >> 7) & 0x7, REG_DEVADDR_H);
> + if (zx2967_i2c_readl(zx_i2c, REG_DEVADDR_H) > 0)
> + zx2967_enable_tenbit(zx_i2c, msgs->addr);
> +
> + for (i = 0; i < num; i++) {
> + ret = zx2967_i2c_xfer_msg(zx_i2c, &msgs[i]);
> + if (ret)
> + return ret;
> + if (num > 1)
Would it be drastic performance impact if you remove this condition
and do sleep unconditionally?
> + usleep_range(1000, 2000);
Why do you need this in any case? Comment, please. Do this for every
non-commented *sleep() call in this driver.
(You may define minimum sleep range, put comment there and use it in
those *sleep() calls)
> + }
> +
> + return num;
> +}
> +#ifdef CONFIG_PM
> +static const struct dev_pm_ops zx2967_i2c_dev_pm_ops = {
> + .suspend = zx2967_i2c_suspend,
> + .resume = zx2967_i2c_resume,
> +};
> +#define ZX2967_I2C_DEV_PM_OPS (&zx2967_i2c_dev_pm_ops)
> +#else
> +#define ZX2967_I2C_DEV_PM_OPS NULL
> +#endif
Remove these ugly #ifdef:s There are suitable macros are available in
pm.h. Like SIMPLE_PM_OPS().
> +static int zx2967_i2c_probe(struct platform_device *pdev)
> +{
> + struct zx2967_i2c_info *zx_i2c;
> + void __iomem *reg_base;
> + struct resource *res;
> + struct clk *clk;
> + int ret;
> + ret = device_property_read_u32(&pdev->dev, "clock-frequency",
> + &zx_i2c->clk_freq);
> + if (ret) {
> + dev_err(&pdev->dev, "missing clock-frequency");
> + return ret;
> + }
How is it used? You enabled clock before this and that clock
apparently has to have frequency > 0. Isn't the same frequency we are
considering here?
> + zx_i2c->reg_base = reg_base;
> + zx_i2c->clk = clk;
> + zx_i2c->dev = &pdev->dev;
> + i2c_set_adapdata(&zx_i2c->adap, zx_i2c);
> + zx_i2c->adap.owner = THIS_MODULE;
Is it still needed?
--
With Best Regards,
Andy Shevchenko
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