On Monday 30 November 2015 21:07:17 Rongrong Zou wrote:
> This is the Low Pin Count driver for Hisilicon Hi1610 SoC. It is used
> for LPC master accessing LPC slave device.
>
> We only implement I/O read and I/O write here, and the 2 interfaces are
> exported for uart driver and ipmi_si driver.
>
> Signed-off-by: Rongrong Zou <[email protected]>
> Signed-off-by: lijianhua <[email protected]>
> ---
> .../bindings/misc/hisilicon,low-pin-count.txt | 11 +
> MAINTAINERS | 5 +
> drivers/misc/Kconfig | 7 +
> drivers/misc/Makefile | 1 +
> drivers/misc/hisi_lpc.c | 292
> +++++++++++++++++++++
> include/linux/hisi_lpc.h | 83 ++++++
> 6 files changed, 399 insertions(+)
This should not be a misc driver.
> create mode 100644
> Documentation/devicetree/bindings/misc/hisilicon,low-pin-count.txt
> create mode 100644 drivers/misc/hisi_lpc.c
> create mode 100644 include/linux/hisi_lpc.h
> diff --git
> a/Documentation/devicetree/bindings/misc/hisilicon,low-pin-count.txt
> b/Documentation/devicetree/bindings/misc/hisilicon,low-pin-count.txt
> new file mode 100644
> index 0000000..05c1e19
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/misc/hisilicon,low-pin-count.txt
> @@ -0,0 +1,11 @@
> +Hisilicon Low Pin Count bus
> +
> +Required properties
> +- compatible: "hisilicon,low-pin-count"
> +- reg specifies low pin count address range
> +
> +Example:
> + lpc_0: lpc@a01b0000 {
> + compatible = "hisilicon,low-pin-count";
> + ret = <0x0 0xa01b0000, 0x0, 0x10000>;
> + };
The name is too generic, unless you can guarantee that Hisilicon has never
before made another implementation of an LPC interface, and never will
again.
I think you should create a child address space here using a
'#address-cells' and '#size-cells'.
> +#define LPC_REG_READ(reg, result) ((result) = readl(reg))
> +
> +#define LPC_REG_WRITE(reg, data) writel((data), (reg))
Remove the obfuscation here.
> +struct hs_lpc_dev *lpc_dev;
Avoid global data structures.
> + LPC_REG_WRITE(lpc_dev->regs + HS_LPC_REG_IRQ_ST, HS_LPC_IRQ_CLEAR);
> + retry = 0;
> + while (0 == (LPC_REG_READ(lpc_dev->regs + HS_LPC_REG_OP_STATUS,
> + lpc_op_state_value) & HS_LPC_STATUS_DILE)) {
> + udelay(1);
> + retry++;
> + if (retry >= 10000) {
> + dev_err(lpc_dev->dev, "lpc W, wait idle time out\n");
> + return -ETIME;
> + }
> + }
Better release the spinlock here and call a sleeping function for the wait.
If the timeout is 10ms, you definitely don't want to keep interrupts disabled
the whole time.
If you can't find a good way to retry after getting the lock back, maybe
use a mutex here that you can keep locked the whole time.
> +void lpc_io_write_byte(u8 value, unsigned long addr)
> +{
> + unsigned long flags;
> + int ret;
> +
> + if (!lpc_dev) {
> + pr_err("device is not register\n!");
> + return;
> + }
> + spin_lock_irqsave(&lpc_dev->lock, flags);
> + ret = lpc_master_write(HS_LPC_CMD_SAMEADDR_SING, HS_LPC_CMD_TYPE_IO,
> + addr, &value, 1);
> + spin_unlock_irqrestore(&lpc_dev->lock, flags);
> +}
> +EXPORT_SYMBOL(lpc_io_write_byte);
Using your own accessor functions sounds wrong here. What you have
is essentially a PCI I/O space, right? As much as we all hate I/O
space (in particular the kind that is not memory mapped), I think this
should be hooked up to the generic inb/outb functions to allow
all the generic device drivers to work.
> diff --git a/include/linux/hisi_lpc.h b/include/linux/hisi_lpc.h
> new file mode 100644
> index 0000000..4cf93ee
> --- /dev/null
> +++ b/include/linux/hisi_lpc.h
Don't do a global header here, just move it into the main file.
Arnd
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