Hello Andy,
>
> On Fri, Jul 14, 2023 at 03:45:22PM +0800, Ryan Chen wrote:
> > Add i2c new register mode driver to support AST2600 i2c new register
> > mode. AST2600 i2c controller have legacy and new register mode. The
> > new register mode have global register support 4 base clock for scl
> > clock selection, and new clock divider mode. The i2c new register mode
> > have separate register set to control i2c master and slave.
>
> ...
>
> + bits.h
>
> > +#include <linux/clk.h>
> > +#include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/err.h>
> > +#include <linux/i2c.h>
> > +#include <linux/i2c-smbus.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/mfd/syscon.h>
>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_irq.h>
>
> You missed property.h
> and these of*.h probably not needed at all, see below.
>
> > +#include <linux/regmap.h>
> > +#include <linux/reset.h>
> > +#include <linux/slab.h>
> > +#include <linux/string_helpers.h>
>
> ...
>
> > +#define AST2600_I2CC_GET_RX_BUFF(x) (((x) >> 8) &
> GENMASK(7, 0))
>
> > +#define AST2600_I2CC_GET_RX_BUF_LEN(x) (((x) >> 24) &
> GENMASK(5, 0))
>
> > +#define AST2600_I2CC_GET_TX_BUF_LEN(x) ((((x) >> 8) &
> GENMASK(4, 0)) + 1)
>
> With right shifts it's better to have GENMASK to be applied first, it will show
> exact MSB of the bitfield.
>
> (Ditto for other cases similar to these)
>
> ...
>
> > +static u32 ast2600_select_i2c_clock(struct ast2600_i2c_bus *i2c_bus)
> > +{
> > + unsigned long base_clk[4];
> > + int baseclk_idx;
> > + u32 clk_div_reg;
> > + u32 scl_low;
> > + u32 scl_high;
> > + int divisor;
> > + int inc = 0;
> > + u32 data;
> > +
> > + regmap_read(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL,
> &clk_div_reg);
> > + for (int i = 0; i < 4; i++) {
>
> See below.
>
> > + base_clk[i] = (i2c_bus->apb_clk * 10) /
> > + (((((clk_div_reg >> (i * 8)) & GENMASK(7, 0)) + 2) * 10) / 2);
>
> Second line is wrongly indented.
>
> > + }
>
> > + if ((i2c_bus->apb_clk / i2c_bus->bus_frequency) <= 32) {
> > + baseclk_idx = 0;
> > + divisor = DIV_ROUND_UP(i2c_bus->apb_clk,
> i2c_bus->bus_frequency);
> > + } else {
>
> > + int i;
> > +
>
> Just add to the definition block:
>
> unsigned int i;
>
> > + for (i = 0; i < 4; i++) {
> > + if ((base_clk[i] / i2c_bus->bus_frequency) <= 32) {
>
> > + baseclk_idx = i + 1;
> > + divisor = DIV_ROUND_UP(base_clk[i],
> i2c_bus->bus_frequency);
>
> These two can be moved outside of the loop
>
> > + break;
> > + }
>
> if ((base_clk[i] / i2c_bus->bus_frequency) <= 32)
> break;
>
> > + }
> > + if (i == 4) {
> > + baseclk_idx = 4;
> > + divisor = DIV_ROUND_UP(base_clk[3],
> i2c_bus->bus_frequency);
>
> > + while ((divisor + inc) > 32) {
> > + inc |= divisor & 0x1;
> > + divisor >>= 1;
>
> unsigned long divisor;
>
> for_each_set_bit(divisor, ...)
>
> I.o.w. think about this, maybe you can refactor with the above.
>
> > + baseclk_idx++;
> > + }
> > + divisor += inc;
>
> } else {
> ...those two lines...
>
> > + }
>
> > + }
> > +
> > + divisor = min_t(int, divisor, 32);
> > + baseclk_idx &= GENMASK(3, 0);
>
> > + scl_low = ((divisor * 9) / 16) - 1;
> > + scl_low = min_t(u32, scl_low, GENMASK(3, 0));
>
> (with the divisor being unsigned long) this can be rewritten as
>
> scl_low = min(divisor * 9 / 16 - 1, GENMASK(3, 0));
>
> which improves type checking and readability.
>
> > + scl_high = (divisor - scl_low - 2) & GENMASK(3, 0);
> > + data = (scl_high - 1) << 20 | scl_high << 16 | scl_low << 12 |
> > +baseclk_idx;
> > +
> > + if (i2c_bus->timeout) {
> > + data |= AST2600_I2CC_TOUTBASECLK(AST_I2C_TIMEOUT_CLK);
> > + data |= AST2600_I2CC_TTIMEOUT(i2c_bus->timeout);
> > + }
> > +
> > + return data;
> > +}
>
> ...
>
> > +static u8 ast2600_i2c_recover_bus(struct ast2600_i2c_bus *i2c_bus) {
> > + int ret = 0;
> > + u32 ctrl;
> > + u32 state;
> > + int r;
>
> > + dev_dbg(i2c_bus->dev, "%d-bus recovery bus [%x]\n", i2c_bus->adap.nr,
> > + readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
>
> Why you can't reuse "state" (assigned below)?
> If not, then something like
>
> /* ...comment that state can be changed... */
> state = ...
> dev_dbg(state);
>
> > + ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +
> > + writel(ctrl & ~(AST2600_I2CC_MASTER_EN | AST2600_I2CC_SLAVE_EN),
> > + i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +
> > + writel(readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL) |
> > +AST2600_I2CC_MASTER_EN,
>
> will it be different from ctrl value?
>
> > + i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +
> > + reinit_completion(&i2c_bus->cmd_complete);
> > + i2c_bus->cmd_err = 0;
> > +
> > + /* Check 0x14's SDA and SCL status */
> > + state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
> > + if (!(state & AST2600_I2CC_SDA_LINE_STS) && (state &
> AST2600_I2CC_SCL_LINE_STS)) {
> > + writel(AST2600_I2CM_RECOVER_CMD_EN, i2c_bus->reg_base +
> AST2600_I2CM_CMD_STS);
> > + r = wait_for_completion_timeout(&i2c_bus->cmd_complete,
> i2c_bus->adap.timeout);
> > + if (r == 0) {
> > + dev_dbg(i2c_bus->dev, "recovery timed out\n");
> > + ret = -ETIMEDOUT;
>
> > + } else {
> > + if (i2c_bus->cmd_err) {
>
> } else if (...) {
>
> > + dev_dbg(i2c_bus->dev, "recovery error\n");
> > + ret = -EPROTO;
> > + }
> > + }
> > + }
> > +
> > + dev_dbg(i2c_bus->dev, "Recovery done [%x]\n",
> > + readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
>
> As above.
>
> > + if (readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF) &
> > +AST2600_I2CC_BUS_BUSY_STS) {
>
> Two sequential reads may give you different values?
>
> > + dev_dbg(i2c_bus->dev, "Can't recover bus [%x]\n",
> > + readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
>
> Again? With this inconsistency it will be "nice" to debug.
>
> > + ret = -EPROTO;
> > + }
> > +
> > + writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > + return ret;
> > +}
>
> ...
>
> > +#ifdef CONFIG_I2C_SLAVE
>
> For (at least) review purposes I recommend to split slave out to the separate
> change. This driver is 16 hundreds LoCs long...
>
> > +#endif
>
> ...
>
> > + } else if (i2c_bus->mode == BUFF_MODE) {
> > + /* buff mode */
> > + cmd |= AST2600_I2CM_RX_BUFF_EN;
>
> > + if (msg->flags & I2C_M_RECV_LEN) {
> > + dev_dbg(i2c_bus->dev, "smbus read\n");
> > + xfer_len = 1;
> > + } else {
> > + if (msg->len > i2c_bus->buf_size) {
> > + xfer_len = i2c_bus->buf_size;
> > + } else {
> > + xfer_len = msg->len;
> > + if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > + cmd |= MASTER_TRIGGER_LAST_STOP;
> > + }
> > + }
>
> This...
>
> > + writel(AST2600_I2CC_SET_RX_BUF_LEN(xfer_len),
> > + i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
> > + } else {
>
> > + /* byte mode */
> > + xfer_len = 1;
> > + if (msg->flags & I2C_M_RECV_LEN) {
> > + dev_dbg(i2c_bus->dev, "smbus read\n");
> > + } else {
> > + if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) {
> > + if (msg->len == 1)
> > + cmd |= MASTER_TRIGGER_LAST_STOP;
> > + }
> > + }
>
> ...and this have a lot in common, can it be deduplicated?
>
> > + }
>
> ...
>
> > + if (msg->len > AST2600_I2C_DMA_SIZE) {
> > + xfer_len = AST2600_I2C_DMA_SIZE;
> > + } else {
> > + if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > + cmd |= AST2600_I2CM_STOP_CMD;
> > + xfer_len = msg->len;
> > + }
>
> See above.
>
> ...
>
> > + u8 wbuf[4];
> > + /* buff mode */
> > + if (msg->len > i2c_bus->buf_size) {
> > + xfer_len = i2c_bus->buf_size;
> > + } else {
> > + if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > + cmd |= AST2600_I2CM_STOP_CMD;
> > + xfer_len = msg->len;
> > + }
> > + if (xfer_len) {
> > + cmd |= AST2600_I2CM_TX_BUFF_EN |
> AST2600_I2CM_TX_CMD;
> > + if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR))
> > + return -ENOMEM;
> > + writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
> > + i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
> > + if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR))
> > + return -ENOMEM;
> > + for (i = 0; i < xfer_len; i++) {
> > + wbuf[i % 4] = msg->buf[i];
> > + if (i % 4 == 3)
>
> > + writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
>
> This is incorrect memory accessor.
>
> > + }
> > + if (--i % 4 != 3)
> > + writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
>
> Ditto.
>
> > + }
>
> ...
>
> > +static int ast2600_i2c_is_irq_error(u32 irq_status)
>
> This function is not boolean, so "_is_" seems misleading.
>
> This is basically error code conversion, something like
>
> ast2600_i2c_irq_err_to_errno(u32 irq_status)
>
> > +{
> > + if (irq_status & AST2600_I2CM_ARBIT_LOSS)
> > + return -EAGAIN;
> > + if (irq_status & (AST2600_I2CM_SDA_DL_TO |
> AST2600_I2CM_SCL_LOW_TO))
> > + return -EBUSY;
> > + if (irq_status & (AST2600_I2CM_ABNORMAL))
> > + return -EPROTO;
> > +
> > + return 0;
> > +}
>
> ...
>
> > + u8 wbuf[4];
> > +
> > + cmd |= AST2600_I2CM_TX_BUFF_EN;
> > + xfer_len = msg->len - i2c_bus->master_xfer_cnt;
> > + if (xfer_len > i2c_bus->buf_size) {
> > + xfer_len = i2c_bus->buf_size;
> > + } else {
> > + if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > + cmd |= AST2600_I2CM_STOP_CMD;
> > + }
> > + for (i = 0; i < xfer_len; i++) {
> > + wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
> > + if (i % 4 == 3)
> > + writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
> > + }
> > + if (--i % 4 != 3)
> > + writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
> > + writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
> > + i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
>
> Wrong memory accessors. You should use something from asm/byteorder.h
> which includes linux/byteorder/generic.h.
>
Are you preferring add comment to explain more by following?
/*
* The controller's buffer register supports dword writes only.
* Therefore, write dwords to the buffer register in a 4-byte aligned,
* and write the remaining unaligned data at the end.
*/
for (i = 0; i < xfer_len; i++) {
wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
/* accumulating 4 bytes of data, write as a Dword to the buffer register */
if (i % 4 == 3)
writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
}
/* less than 4 bytes of remaining data, write the remaining part as a Dword */
if (--i % 4 != 3)
writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
Or more columns (use get_unaligned_le32(wbuf); ) by following.
for (i = 0; i < xfer_len; i++) {
wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
if (i % 4 == 3) {
wbuf_dword = get_unaligned_le32(wbuf);
writel(wbuf_dword, i2c_bus->buf_base + i - 3);
}
}
if (--i % 4 != 3) {
wbuf_dword = get_unaligned_le32(wbuf);
writel(wbuf_dword, i2c_bus->buf_base + i - (i % 4));
}
> ...
>
> > +#ifdef CONFIG_I2C_SLAVE
> > + /* Workaround for master/slave package mode enable rx done stuck
> issue
> > + * When master go for first read (RX_DONE), slave mode will also
> effect
> > + * Then controller will send nack, not operate anymore.
> > + */
>
> /*
> * Wrong style of multi-line
> * comments. You need to fix
> * them in the entire driver.
> */
>
> > + if (readl(i2c_bus->reg_base + AST2600_I2CS_CMD_STS) &
> AST2600_I2CS_PKT_MODE_EN) {
> > + u32 slave_cmd = readl(i2c_bus->reg_base +
> AST2600_I2CS_CMD_STS);
> > +
> > + writel(0, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
> > + writel(slave_cmd, i2c_bus->reg_base +
> AST2600_I2CS_CMD_STS);
> > + }
> > + fallthrough;
> > +#endif
>
> ...
>
> > +static int ast2600_i2c_master_irq(struct ast2600_i2c_bus *i2c_bus) {
> > + u32 sts = readl(i2c_bus->reg_base + AST2600_I2CM_ISR);
> > + u32 ier = readl(i2c_bus->reg_base + AST2600_I2CM_IER);
> > + u32 ctrl = 0;
>
> Redundant assignment.
>
> > + if (!i2c_bus->alert_enable)
> > + sts &= ~AST2600_I2CM_SMBUS_ALT;
> > +
> > + if (AST2600_I2CM_BUS_RECOVER_FAIL & sts) {
> > + writel(AST2600_I2CM_BUS_RECOVER_FAIL, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > + ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > + writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > + writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > + i2c_bus->cmd_err = -EPROTO;
> > + complete(&i2c_bus->cmd_complete);
> > + return 1;
> > + }
> > +
> > + if (AST2600_I2CM_BUS_RECOVER & sts) {
> > + writel(AST2600_I2CM_BUS_RECOVER, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > + i2c_bus->cmd_err = 0;
> > + complete(&i2c_bus->cmd_complete);
> > + return 1;
> > + }
> > +
> > + if (AST2600_I2CM_SMBUS_ALT & sts) {
> > + if (ier & AST2600_I2CM_SMBUS_ALT) {
> > + /* Disable ALT INT */
> > + writel(ier & ~AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base +
> AST2600_I2CM_IER);
> > + i2c_handle_smbus_alert(i2c_bus->ara);
> > + writel(AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > + dev_err(i2c_bus->dev,
> > + "ast2600_master_alert_recv bus id %d, Disable Alt, Please
> Imple\n",
> > + i2c_bus->adap.nr);
> > + return 1;
> > + }
> > + }
> > +
> > + i2c_bus->cmd_err = ast2600_i2c_is_irq_error(sts);
> > + if (i2c_bus->cmd_err) {
> > + writel(AST2600_I2CM_PKT_DONE, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > + complete(&i2c_bus->cmd_complete);
> > + return 1;
> > + }
> > +
> > + if (AST2600_I2CM_PKT_DONE & sts) {
> > + ast2600_i2c_master_package_irq(i2c_bus, sts);
> > + return 1;
> > + }
> > +
> > + return 0;
> > +}
>
> ...
>
> > + if (of_property_read_bool(pdev->dev.of_node, "multi-master"))
> > + i2c_bus->multi_master = true;
> > + else
> > + fun_ctrl |= AST2600_I2CC_MULTI_MASTER_DIS;
>
> i2c_bus->multi_master = device_property_read_bool(&pdev->dev,
> "multi-master");
> if (!i2c_bus->multi_master)
> fun_ctrl |= AST2600_I2CC_MULTI_MASTER_DIS;
>
> ...
>
> > + struct device_node *np = pdev->dev.of_node;
>
> It should use dev, but see below.
>
> > + struct device *dev = &pdev->dev;
> > + struct ast2600_i2c_bus *i2c_bus;
> > + struct resource *res;
> > + u32 global_ctrl;
>
> > + int ret = 0;
>
> Do you need this assignment?
>
> ...
>
> > + i2c_bus->buf_base = devm_platform_ioremap_resource(pdev, 1);
>
> > + if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
>
> Why not positive check?
>
> > + i2c_bus->buf_size = resource_size(res) / 2;
> > + else
> > + i2c_bus->mode = BYTE_MODE;
> > + }
>
> ...
>
> > + ret = of_property_read_u32(dev->of_node,
> > + "i2c-scl-clk-low-timeout-us",
> > + &i2c_bus->timeout);
>
> device_property_read_u32()
>
> > + if (!ret)
> > + i2c_bus->timeout /= 4096;
>
> ...
>
> > + ret = device_property_read_u32(&pdev->dev, "clock-frequency",
> &i2c_bus->bus_frequency);
> > + if (ret < 0) {
> > + dev_warn(dev, "Could not read clock-frequency property\n");
> > + i2c_bus->bus_frequency = I2C_MAX_STANDARD_MODE_FREQ;
> > + }
>
> Use standard API from I2C core for this.
>
> ...
>
> > + if (of_property_read_bool(dev->of_node, "smbus-alert")) {
>
> device_property_read_bool()
>
> Doesn't I2C core handle this property?
>
> > + i2c_bus->alert_enable = true;
> > + i2c_bus->ara = i2c_new_smbus_alert_device(&i2c_bus->adap,
> &i2c_bus->alert_data);
> > + if (!i2c_bus->ara)
> > + dev_warn(dev, "Failed to register ARA client\n");
> > +
> > + writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER |
> AST2600_I2CM_SMBUS_ALT,
> > + i2c_bus->reg_base + AST2600_I2CM_IER);
> > + } else {
> > + i2c_bus->alert_enable = false;
> > + /* Set interrupt generation of I2C master controller */
> > + writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER,
> > + i2c_bus->reg_base + AST2600_I2CM_IER);
> > + }
>
> ...
>
> > + devm_free_irq(&pdev->dev, i2c_bus->irq, i2c_bus);
>
> Why explicit call?
>
> ...
>
> > + dmam_free_coherent(i2c_bus->dev, I2C_SLAVE_MSG_BUF_SIZE,
> > + i2c_bus->slave_dma_buf, i2c_bus->slave_dma_addr);
>
> Ditto.
>
> ...
>
> It looks to me like you ignored part of my comments. If so, I would like to know
> why.
>
> --
> With Best Regards,
> Andy Shevchenko
>
