Thanks Wolfram for the careful review
On 09/20/2014 01:18 AM, Wolfram Sang wrote:
Hi,
thanks for the submission.
--- /dev/null
+++ b/drivers/i2c/busses/i2c-hix5hd2.c
@@ -0,0 +1,573 @@
+/*
+ * Copyright (c) 2014 Linaro Ltd.
+ * Copyright (c) 2014 Hisilicon Limited.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * publishhed by the Free Software Foundation.
"publishhed"
OK.
+ *
+ * Now only support 7 bit address.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
I think there should be at least of.h, too.
The of.h is already in i2c.h
include/linux/i2c.h:33:#include <linux/of.h>
+struct hix5hd2_i2c {
+ struct i2c_adapter adap;
+ struct i2c_msg *msg;
+ unsigned int msg_ptr; /* msg index */
Comment seems wrong. It looks to me as the msg buffer index. If so, the
variable name is also confusing.
Change to msg_idx & msg_len.
+ unsigned int len; /* msg length */
+ int stop;
+ struct completion msg_complete;
+
+ unsigned int irq;
That can be a local variable.
Yes
+ void __iomem *regs;
+ struct clk *clk;
+ struct device *dev;
+ spinlock_t lock; /* IRQ synchronization */
+
+ int err;
+ enum hix5hd2_i2c_state state;
+ enum hix5hd2_i2c_speed speed_mode;
Where is this needed?
will remove
+
+ /* Controller frequency */
+ unsigned int s_clock;
+};
+
+static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c *i2c)
+{
+ u32 rate, val;
+ u32 sclh, scll, sysclock;
+
+ /* close all i2c interrupt */
+ val = readl_relaxed(i2c->regs + HIX5I2C_CTRL);
+ writel_relaxed(val & (~I2C_UNMASK_TOTAL), i2c->regs + HIX5I2C_CTRL);
+
+ rate = i2c->s_clock;
+ sysclock = clk_get_rate(i2c->clk);
+ sclh = (sysclock / (rate * 2)) / 2 - 1;
+ writel_relaxed(sclh, i2c->regs + HIX5I2C_SCL_H);
+ scll = (sysclock / (rate * 2)) / 2 - 1;
scll and sclh use the same formula? Have you measured the setup
frequency with a scope?
Yes, it is confusing, will use the same vector scl instead.
The value is same means sclk high voltage and low voltage keep same time.
+ writel_relaxed(scll, i2c->regs + HIX5I2C_SCL_L);
+
+ /* restore original interrupt*/
+ writel_relaxed(val, i2c->regs + HIX5I2C_CTRL);
+
+ dev_dbg(i2c->dev, "%s: sysclock=%d, rate=%d, sclh=%d, scll=%d\n",
+ __func__, sysclock, rate, sclh, scll);
+}
+
+static void hix5hd2_rw_over(struct hix5hd2_i2c *i2c)
+{
+ if (HIX5I2C_STAT_SND_STOP == i2c->state)
To be honest, I don't like having the constant on the left side. It
is far easier to read if they are on the right side. Plus, we have gcc
warnings to prevent the "=" and "==" mistake. Please switch them around
in this driver.
Got it.
+ dev_dbg(i2c->dev, "%s: rw and send stop over\n", __func__);
+ else
+ dev_dbg(i2c->dev, "%s: have not data to send\n", __func__);
+
+ i2c->state = HIX5I2C_STAT_RW_SUCCESS;
+ i2c->err = 0;
+}
+
...
+ /* handle error */
+ if (int_status & I2C_ARBITRATE_INTR) {
+ /*Bus error */
Space missing in front of "Bus". If this is an arbitration lost error,
then please use -EAGAIN. Check Documentation/i2c/fault-codes for the
convention.
OK.
+ dev_dbg(i2c->dev, "ARB bus loss\n");
+ i2c->err = -ENXIO;
+ i2c->state = HIX5I2C_STAT_RW_ERR;
+ goto stop;
+ } else if (int_status & I2C_ACK_INTR) {
+ /* ack error */
+ dev_dbg(i2c->dev, "No ACK from device\n");
+ i2c->err = -ENXIO;
+ i2c->state = HIX5I2C_STAT_RW_ERR;
+ goto stop;
+ }
+
+static void hix5hd2_i2c_message_start(struct hix5hd2_i2c *i2c, int stop)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&i2c->lock, flags);
+ hix5hd2_i2c_clr_all_irq(i2c);
+ hix5hd2_i2c_enable_irq(i2c);
+
+ if (i2c->msg->flags & I2C_M_RD)
+ writel_relaxed(i2c->msg->addr | HIX5I2C_READ_OPERATION,
+ i2c->regs + HIX5I2C_TXR);
+ else
+ writel_relaxed(i2c->msg->addr & HIX5I2C_WRITE_OPERATION,
+ i2c->regs + HIX5I2C_TXR);
??? Does this really work? i2c->msg->addr should be left shifted by 1?
Double checked, it is because the test applictaion do the left shift.
Yes, will do the left shift by 1.
+
+ writel_relaxed(I2C_WRITE | I2C_START, i2c->regs + HIX5I2C_COM);
+ spin_unlock_irqrestore(&i2c->lock, flags);
+}
+
+static int hix5hd2_i2c_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct hix5hd2_i2c *i2c;
+ struct resource *mem;
+ unsigned int op_clock;
+ int ret;
+
+ i2c = devm_kzalloc(&pdev->dev, sizeof(struct hix5hd2_i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ if (of_property_read_u32(np, "clock-frequency", &op_clock)) {
+ /* use default value */
+ i2c->speed_mode = HIX5I2C_HIG_SPD;
+ i2c->s_clock = HIX5I2C_HS_TX_CLOCK;
Please use 100kHz as the default. This is the speed devices should
support. 400kHz is optional. And I think 100000 is easier to read than a
define.
OK.
+ } else {
+ if (op_clock >= HIX5I2C_HS_TX_CLOCK) {
+ i2c->speed_mode = HIX5I2C_HIG_SPD;
+ i2c->s_clock = HIX5I2C_HS_TX_CLOCK;
So, if the speed is bigger than 400kHz, it will be capped down to
400kHz? Is that true? Then, the user should be informed about that.
Will add dev_warn to notify.
+ } else {
+ i2c->speed_mode = HIX5I2C_NORMAL_SPD;
+ i2c->s_clock = op_clock;
+ }
+ }
+
...
+ i2c->adap.owner = THIS_MODULE;
+ i2c->adap.algo = &hix5hd2_i2c_algorithm;
Single space as indentation.
Got it.
Thanks
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