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Date: Fri, 09 Oct 2015 12:29:32 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: wangxfdu@...il.com, xiang.a.wang@...el.com, wsa@...-dreams.de,
jarkko.nikula@...ux.intel.com, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] i2c: designware: add High-speed mode support
On Fri, 2015-10-09 at 16:47 +0800, wangxfdu@...il.com wrote:
> From: Xiang Wang <xiang.a.wang@...el.com>
>
> 1. Add High-speed mode support in designware core
> 2. Add function i2c_dw_acpi_setup_speed to determine
> the bus speed from ACPI table.
>
> Signed-off-by: Xiang Wang <xiang.a.wang@...el.com>
> ---
> drivers/i2c/busses/i2c-designware-core.c | 88
> ++++++++++++++++++++++++++++++++
> drivers/i2c/busses/i2c-designware-core.h | 11 ++++
> 2 files changed, 99 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-designware-core.c
> b/drivers/i2c/busses/i2c-designware-core.c
> index 6f19a33..f5c0d18 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -30,6 +30,7 @@
> #include <linux/pm_runtime.h>
> #include <linux/delay.h>
> #include <linux/module.h>
> +#include <linux/acpi.h>
Shouldn't be a part of platform driver?
> #include "i2c-designware-core.h"
>
> /*
> @@ -42,6 +43,8 @@
> #define DW_IC_SS_SCL_LCNT 0x18
> #define DW_IC_FS_SCL_HCNT 0x1c
> #define DW_IC_FS_SCL_LCNT 0x20
> +#define DW_IC_HS_SCL_HCNT 0x24
> +#define DW_IC_HS_SCL_LCNT 0x28
> #define DW_IC_INTR_STAT 0x2c
> #define DW_IC_INTR_MASK 0x30
> #define DW_IC_RAW_INTR_STAT 0x34
> @@ -358,6 +361,16 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
> dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
> dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt,
> lcnt);
>
> + if (dev->hs_hcnt && dev->hs_lcnt) {
> + hcnt = dev->hs_hcnt;
> + lcnt = dev->hs_lcnt;
> +
> + dw_writel(dev, hcnt, DW_IC_HS_SCL_HCNT);
> + dw_writel(dev, lcnt, DW_IC_HS_SCL_LCNT);
> + dev_dbg(dev->dev, "High-speed mode HCNT:LCNT =
> %d:%d\n",
> + hcnt, lcnt);
> + }
> +
> /* Configure SDA Hold Time if required */
> if (dev->sda_hold_time) {
> reg = dw_readl(dev, DW_IC_COMP_VERSION);
> @@ -381,6 +394,81 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
> }
> EXPORT_SYMBOL_GPL(i2c_dw_init);
>
> +#ifdef CONFIG_ACPI
> +static int i2c_dw_acpi_get_freq(struct acpi_resource *ares, void
> *data)
> +{
> + struct dw_i2c_dev *i2c = data;
> + struct acpi_resource_i2c_serialbus *sb;
> + u32 i2c_speed;
> +
> + if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
> + sb = &ares->data.i2c_serial_bus;
> +
> + if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> + i2c_speed = sb->connection_speed;
> + if (i2c_speed == DW_STD_SPEED) {
> + i2c->master_cfg &=
> ~DW_IC_SPEED_MASK;
> + i2c->master_cfg |=
> DW_IC_CON_SPEED_STD;
> + } else if (i2c_speed == DW_FAST_SPEED) {
> + i2c->master_cfg &=
> ~DW_IC_SPEED_MASK;
> + i2c->master_cfg |=
> DW_IC_CON_SPEED_FAST;
> + } else if (i2c_speed == DW_HIGH_SPEED) {
> + i2c->master_cfg &=
> ~DW_IC_SPEED_MASK;
> + i2c->master_cfg |=
> DW_IC_CON_SPEED_HIGH;
> + } else {
> + dev_err(i2c->dev, "unsupported
> speed: %d\n",
> + i2c_speed);
> + }
> +
> + dev_dbg(i2c->dev, "i2c device speed from
> acpi = %d\n",
> + i2c_speed);
> + }
> + }
> +
> + return 1;
> +}
> +
> +static acpi_status acpi_i2c_find_device_speed(acpi_handle handle,
> u32 level,
> + void *data, void
> **return_value)
> +{
> + struct dw_i2c_dev *i2c = data;
> + struct list_head resource_list;
> + struct acpi_device *adev;
> +
> + if (acpi_bus_get_device(handle, &adev))
> + return AE_OK;
> + if (acpi_bus_get_status(adev) || !adev->status.present)
> + return AE_OK;
> +
> + INIT_LIST_HEAD(&resource_list);
> + acpi_dev_get_resources(adev, &resource_list,
> + i2c_dw_acpi_get_freq, i2c);
> + acpi_dev_free_resource_list(&resource_list);
> +
> + return AE_OK;
> +}
> +
> +void i2c_dw_acpi_setup_speed(struct device *pdev, struct dw_i2c_dev
> *dev)
> +{
> + acpi_handle handle = ACPI_HANDLE(pdev);
> + acpi_status status;
> +
> + if (handle == NULL)
> + return;
> +
> + /* Find I2C adapter bus frequency */
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
> + acpi_i2c_find_device_speed,
> NULL,
> + dev, NULL);
> + if (ACPI_FAILURE(status))
> + dev_warn(pdev, "failed to get I2C bus freq\n");
> +}
> +
> +#else
> +void i2c_dw_acpi_setup_speed(struct device *pdev, struct dw_i2c_dev
> *dev) {}
> +#endif
> +EXPORT_SYMBOL_GPL(i2c_dw_acpi_setup_speed);
> +
> /*
> * Waiting for bus not busy
> */
> diff --git a/drivers/i2c/busses/i2c-designware-core.h
> b/drivers/i2c/busses/i2c-designware-core.h
> index 9630222..16f53d8 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -24,12 +24,17 @@
>
>
> #define DW_IC_CON_MASTER 0x1
> +#define DW_IC_SPEED_MASK 0x6
> #define DW_IC_CON_SPEED_STD 0x2
> #define DW_IC_CON_SPEED_FAST 0x4
> +#define DW_IC_CON_SPEED_HIGH 0x6
> #define DW_IC_CON_10BITADDR_MASTER 0x10
> #define DW_IC_CON_RESTART_EN 0x20
> #define DW_IC_CON_SLAVE_DISABLE 0x40
>
> +#define DW_STD_SPEED 100000
> +#define DW_FAST_SPEED 400000
> +#define DW_HIGH_SPEED 3400000
>
> /**
> * struct dw_i2c_dev - private i2c-designware data
> @@ -61,6 +66,8 @@
> * @ss_lcnt: standard speed LCNT value
> * @fs_hcnt: fast speed HCNT value
> * @fs_lcnt: fast speed LCNT value
> + * @hs_hcnt: high speed HCNT value
> + * @hs_lcnt: high speed LCNT value
> * @acquire_lock: function to acquire a hardware lock on the bus
> * @release_lock: function to release a hardware lock on the bus
> * @pm_runtime_disabled: true if pm runtime is disabled
> @@ -104,6 +111,8 @@ struct dw_i2c_dev {
> u16 ss_lcnt;
> u16 fs_hcnt;
> u16 fs_lcnt;
> + u16 hs_hcnt;
> + u16 hs_lcnt;
> int (*acquire_lock)(struct dw_i2c_dev
> *dev);
> void (*release_lock)(struct dw_i2c_dev
> *dev);
> bool pm_runtime_disabled;
> @@ -114,6 +123,8 @@ struct dw_i2c_dev {
>
> extern u32 dw_readl(struct dw_i2c_dev *dev, int offset);
> extern void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset);
> +extern void i2c_dw_acpi_setup_speed(struct device *pdev,
> + struct dw_i2c_dev *dev);
> extern int i2c_dw_init(struct dw_i2c_dev *dev);
> extern int i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg
> msgs[],
> int num);
--
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy
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