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Message-ID: <CAHp75VfjS-Wdun65Tx8xEniTVfiMASu022K9ipVRwxJLE8SXkg@mail.gmail.com>
Date: Fri, 20 Jan 2017 23:45:15 +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>,
shawnguo@...nel.org, xie.baoyou@....com.cn,
chen.chaokai@....com.cn, wang.qiang01@....com.cn
Subject: Re: [PATCH v1 3/3] i2c: zx2967: add i2c controller driver for ZTE's
zx2967 family
On Fri, Jan 20, 2017 at 10:43 AM, Baoyou Xie <baoyou.xie@...aro.org> wrote:
> This patch adds i2c controller driver for ZTE's zx2967 family.
>
> +config I2C_ZX2967
> + bool "ZTE zx2967 I2C support"
No module?
> + depends on ARCH_ZX
> + default y
Would architecture selects it instead?
> + help
> + Selecting this option will add ZX I2C driver.
> + If unsure, say y.
Two sentences about the same in spite 'default y'.
> +#define BW1 (u32)1
Do you really need casting?
> +#define I2C_STOP 0
> +#define I2C_MASTER (1 << 0)
BIT(0) ?
And so further.
> +#define I2C_INT_MASK 0x3f
GENMASK(6, 0) ?
> +#define I2C_ERROR_MASK (I2C_ERROR_DATA | I2C_ERROR_DEVICE)
Ditto.
GENMASK() with explicit numbers.
> +static int zx2967_i2c_flush_fifos(struct zx2967_i2c_info *zx_i2c)
> +{
> + u32 val = 0;
> + u32 offset = 0;
Useless assignments.
> +
> + if (zx_i2c->msg_rd) {
> + offset = REG_RDCONF;
> + val = I2C_RFIFO_RESET;
> + } else {
> + offset = REG_WRCONF;
> + val = I2C_WFIFO_RESET;
> + }
> +static int zx2967_i2c_empty_rx_fifo(struct zx2967_i2c_info *zx_i2c, u32 size)
> +{
> + u8 val[I2C_FIFO_MAX] = {0};
> + int i = 0;
Ditto.
> +
> + if (size == 0) {
Would it be the case?
> + dev_err(zx_i2c->dev, "size is invalid\n");
> + return -EINVAL;
> + }
And what happens even in that case if you just remove this check?
> +
> + zx2967_i2c_readsb(zx_i2c, val, REG_DATA, size);
> + for (i = 0; i < size; i++) {
> + *(zx_i2c->buf++) = val[i];
> + zx_i2c->residue--;
> + if (zx_i2c->residue <= 0)
> + break;
> +static int zx2967_i2c_fill_tx_fifo(struct zx2967_i2c_info *zx_i2c)
> +{
> + u8 *buf = zx_i2c->buf;
> + size_t residue = zx_i2c->residue;
> +
> + if (residue == 0) {
> + dev_err(zx_i2c->dev, "residue is %d\n", (int)residue);
> + return -EINVAL;
> + }
Ditto.
> +static void zx2967_enable_tenbit(struct zx2967_i2c_info *zx_i2c, __u16 addr)
> +{
> + u16 val = ((addr >> 7) & 0x7);
Redundant parens.
> + if (val > 0) {
if (!val)
return;
> +static int zx2967_i2c_xfer_msg(struct zx2967_i2c_info *zx_i2c,
> + struct i2c_msg *msg
> +{
> + unsigned long time_left = 0;
> + unsigned int i = 0;
Redundant assignment.
> +
> + if (msg->len == 0)
if (!msg...)
> + return -EINVAL;
> +static int zx2967_i2c_xfer(struct i2c_adapter *adap,
> + struct i2c_msg *msgs, int num)
> +{
> + int i;
> + int ret = 0;
Redundant. See below.
> + struct zx2967_i2c_info *zx_i2c = i2c_get_adapdata(adap);
Reverse tree, please.
> +
> + 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++) {
int ret;
> + ret = zx2967_i2c_xfer_msg(zx_i2c, &msgs[i]);
> + if (num > 1)
> + usleep_range(1000, 2000);
> + if (ret)
> + break;
return ret;
> + }
> +
> + return ret ?: i;
return i;
And looking now, how i can't be num here?
> +}
> +{
> + struct zx2967_i2c_info *zx_i2c = i2c_get_adapdata(adap);
> + u32 val;
> + u8 buf[2];
> + unsigned long time_left;
Reverse tree.
> + usleep_range(1000, 2000);
> + switch (size) {
> + case I2C_SMBUS_BYTE:
> + case I2C_SMBUS_BYTE_DATA:
> + val = zx2967_i2c_readl(zx_i2c, REG_DATA);
> + data->byte = val;
> + break;
> + case I2C_SMBUS_WORD_DATA:
> + case I2C_SMBUS_PROC_CALL:
> + buf[0] = zx2967_i2c_readl(zx_i2c, REG_DATA);
> + buf[1] = zx2967_i2c_readl(zx_i2c, REG_DATA);
> + data->word = (buf[0] << 8) | buf[1];
> + break;
> + default:
> + dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
I would revisit those several loooong functions for splitting/refactoring.
> +
> +static u32 zx2967_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
> + I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
> + I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
> + I2C_FUNC_I2C | I2C_FUNC_SMBUS_I2C_BLOCK;
> +}
It's just
#define XXX YY1 | YY2 | ...
> +#ifdef CONFIG_PM
> +static int zx2967_i2c_suspend(struct device *dev)
Switch to __maybe_unuse.
> +static int zx2967_i2c_probe(struct platform_device *pdev)
> +{
> + struct resource *res;
> + struct zx2967_i2c_info *zx_i2c = NULL;
Redundant assignment.
> + struct clk *clk;
> + void __iomem *reg_base;
Reverse tree for all above until top of this function.
> + int ret = 0;
Redundant assignment.
> +
> + zx_i2c = devm_kzalloc(&pdev->dev, sizeof(*zx_i2c), GFP_KERNEL);
> + if (!zx_i2c)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(&pdev->dev, "missing io resource\n");
> + return -EINVAL;
> + }
> +
Completely redundant lines of code.
> + reg_base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(reg_base))
> + return PTR_ERR(reg_base);
> +
> + clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "missing controller clock");
> + return PTR_ERR(clk);
> + }
> +
> + ret = clk_prepare_enable(clk);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to enable i2c_clk\n");
> + return ret;
> + }
> +
> + of_property_read_u32(pdev->dev.of_node,
> + "clock-frequency", &zx_i2c->clk_freq);
devce_property_read_uXX();
> + zx_i2c->reg_base = reg_base;
> + zx_i2c->clk = clk;
> + zx_i2c->irq = platform_get_irq(pdev, 0);
Is this optional?
Otherwise has to be checked.
> + zx_i2c->id = pdev->id;
> + zx_i2c->dev = &pdev->dev;
> +
> + zx_i2c->pin_scl = devm_pinctrl_get_select(&pdev->dev, "scl");
> + if (IS_ERR(zx_i2c->pin_scl))
> + dev_info(&pdev->dev, "scl pin is not specified in dts\n");
> +
> + zx_i2c->pin_sda = devm_pinctrl_get_select(&pdev->dev, "sda");
> + if (IS_ERR(zx_i2c->pin_sda))
> + dev_info(&pdev->dev, "sda pin is not specified in dts\n");
> +
> + spin_lock_init(&zx_i2c->lock);
> + init_completion(&zx_i2c->complete);
> + platform_set_drvdata(pdev, zx_i2c);
> +
> + ret = zx2967_i2c_reset_hardware(zx_i2c);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to initialize i2c controller\n");
> + goto unprepare_clk;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, zx_i2c->irq,
> + zx2967_i2c_isr, 0, dev_name(&pdev->dev), zx_i2c);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to request irq %i\n", zx_i2c->irq);
> + goto unprepare_clk;
> + }
> +
> + i2c_set_adapdata(&zx_i2c->adap, zx_i2c);
> + zx_i2c->adap.owner = THIS_MODULE;
Do you need this?
> + zx_i2c->adap.class = I2C_CLASS_DEPRECATED;
> + strlcpy(zx_i2c->adap.name, "zx2967 i2c adapter",
> + sizeof(zx_i2c->adap.name));
> + zx_i2c->adap.algo = &zx2967_i2c_algo;
> + zx_i2c->adap.dev.parent = &pdev->dev;
> + zx_i2c->adap.nr = pdev->id;
> + zx_i2c->adap.dev.of_node = pdev->dev.of_node;
> +
> + ret = i2c_add_numbered_adapter(&zx_i2c->adap);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to add zx2967 i2c adapter\n");
> + goto unprepare_clk;
> + }
> +
> + return 0;
> +
> +unprepare_clk:
err_clk_unprepare:
> + clk_unprepare(zx_i2c->clk);
Perhaps clk_disable_unprepare();
> + return ret;
> +}
> +
> +static int zx2967_i2c_remove(struct platform_device *pdev)
> +{
> + struct zx2967_i2c_info *zx_i2c = platform_get_drvdata(pdev);
> +
> + i2c_del_adapter(&zx_i2c->adap);
> + clk_unprepare(zx_i2c->clk);
Ditto.
> +
> + return 0;
> +}
> +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@...aro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 I2C Bus Controller driver");
> +MODULE_LICENSE("GPL v2");
When bool in Kconfig this all redundant.
--
With Best Regards,
Andy Shevchenko
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