[PATCHv3 4/4] ACPI / LPSS: support for fractional divider clock
From: Heikki Krogerus
Date: Mon May 19 2014 - 07:42:30 EST
This creates fractional divider type clock for the ones that
have it. It is needed by the UART driver as the clock rate must
accommodate to the requested baud rate.
Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
---
drivers/acpi/acpi_lpss.c | 75 +++++++++++++++++++++++++++++++++---------------
1 file changed, 52 insertions(+), 23 deletions(-)
Hi Rafael,
I had to make one more version of this patch..
This changes also the Broadwells to use lpt_i2c_dev_desc with the I2C
devices. Just like on Haswells, on Broadwells the I2C does not have
the dividers, just the gate. No other changes.
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index c314d70..0576423 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -29,6 +29,7 @@ ACPI_MODULE_NAME("acpi_lpss");
#define LPSS_LTR_SIZE 0x18
/* Offsets relative to LPSS_PRIVATE_OFFSET */
+#define LPSS_CLK_DIVIDER_DEF_MASK (BIT(1) | BIT(16))
#define LPSS_GENERAL 0x08
#define LPSS_GENERAL_LTR_MODE_SW BIT(2)
#define LPSS_GENERAL_UART_RTS_OVRD BIT(3)
@@ -60,6 +61,7 @@ struct lpss_device_desc {
bool ltr_required;
unsigned int prv_offset;
size_t prv_size_override;
+ bool clk_divider;
bool clk_gate;
bool save_ctx;
struct lpss_shared_clock *shared_clock;
@@ -97,6 +99,14 @@ static struct lpss_device_desc lpt_dev_desc = {
.clk_required = true,
.prv_offset = 0x800,
.ltr_required = true,
+ .clk_divider = true,
+ .clk_gate = true,
+};
+
+static struct lpss_device_desc lpt_i2c_dev_desc = {
+ .clk_required = true,
+ .prv_offset = 0x800,
+ .ltr_required = true,
.clk_gate = true,
};
@@ -104,6 +114,7 @@ static struct lpss_device_desc lpt_uart_dev_desc = {
.clk_required = true,
.prv_offset = 0x800,
.ltr_required = true,
+ .clk_divider = true,
.clk_gate = true,
.setup = lpss_uart_setup,
};
@@ -125,31 +136,21 @@ static struct lpss_device_desc byt_pwm_dev_desc = {
.shared_clock = &pwm_clock,
};
-static struct lpss_shared_clock uart_clock = {
- .name = "uart_clk",
- .rate = 44236800,
-};
-
static struct lpss_device_desc byt_uart_dev_desc = {
.clk_required = true,
.prv_offset = 0x800,
+ .clk_divider = true,
.clk_gate = true,
.save_ctx = true,
- .shared_clock = &uart_clock,
.setup = lpss_uart_setup,
};
-static struct lpss_shared_clock spi_clock = {
- .name = "spi_clk",
- .rate = 50000000,
-};
-
static struct lpss_device_desc byt_spi_dev_desc = {
.clk_required = true,
.prv_offset = 0x400,
+ .clk_divider = true,
.clk_gate = true,
.save_ctx = true,
- .shared_clock = &spi_clock,
};
static struct lpss_device_desc byt_sdio_dev_desc = {
@@ -175,8 +176,8 @@ static const struct acpi_device_id acpi_lpss_device_ids[] = {
/* Lynxpoint LPSS devices */
{ "INT33C0", (unsigned long)&lpt_dev_desc },
{ "INT33C1", (unsigned long)&lpt_dev_desc },
- { "INT33C2", (unsigned long)&lpt_dev_desc },
- { "INT33C3", (unsigned long)&lpt_dev_desc },
+ { "INT33C2", (unsigned long)&lpt_i2c_dev_desc },
+ { "INT33C3", (unsigned long)&lpt_i2c_dev_desc },
{ "INT33C4", (unsigned long)&lpt_uart_dev_desc },
{ "INT33C5", (unsigned long)&lpt_uart_dev_desc },
{ "INT33C6", (unsigned long)&lpt_sdio_dev_desc },
@@ -193,8 +194,8 @@ static const struct acpi_device_id acpi_lpss_device_ids[] = {
{ "INT3430", (unsigned long)&lpt_dev_desc },
{ "INT3431", (unsigned long)&lpt_dev_desc },
- { "INT3432", (unsigned long)&lpt_dev_desc },
- { "INT3433", (unsigned long)&lpt_dev_desc },
+ { "INT3432", (unsigned long)&lpt_i2c_dev_desc },
+ { "INT3433", (unsigned long)&lpt_i2c_dev_desc },
{ "INT3434", (unsigned long)&lpt_uart_dev_desc },
{ "INT3435", (unsigned long)&lpt_uart_dev_desc },
{ "INT3436", (unsigned long)&lpt_sdio_dev_desc },
@@ -222,9 +223,11 @@ static int register_device_clock(struct acpi_device *adev,
{
const struct lpss_device_desc *dev_desc = pdata->dev_desc;
struct lpss_shared_clock *shared_clock = dev_desc->shared_clock;
+ const char *devname = dev_name(&adev->dev);
struct clk *clk = ERR_PTR(-ENODEV);
struct lpss_clk_data *clk_data;
- const char *parent;
+ const char *parent, *clk_name;
+ void __iomem *prv_base;
if (!lpss_clk_dev)
lpt_register_clock_device();
@@ -235,7 +238,7 @@ static int register_device_clock(struct acpi_device *adev,
if (dev_desc->clkdev_name) {
clk_register_clkdev(clk_data->clk, dev_desc->clkdev_name,
- dev_name(&adev->dev));
+ devname);
return 0;
}
@@ -244,6 +247,7 @@ static int register_device_clock(struct acpi_device *adev,
return -ENODATA;
parent = clk_data->name;
+ prv_base = pdata->mmio_base + dev_desc->prv_offset;
if (shared_clock) {
clk = shared_clock->clk;
@@ -257,16 +261,41 @@ static int register_device_clock(struct acpi_device *adev,
}
if (dev_desc->clk_gate) {
- clk = clk_register_gate(NULL, dev_name(&adev->dev), parent, 0,
- pdata->mmio_base + dev_desc->prv_offset,
- 0, 0, NULL);
- pdata->clk = clk;
+ clk = clk_register_gate(NULL, devname, parent, 0,
+ prv_base, 0, 0, NULL);
+ parent = devname;
+ }
+
+ if (dev_desc->clk_divider) {
+ /* Prevent division by zero */
+ if (!readl(prv_base))
+ writel(LPSS_CLK_DIVIDER_DEF_MASK, prv_base);
+
+ clk_name = kasprintf(GFP_KERNEL, "%s-div", devname);
+ if (!clk_name)
+ return -ENOMEM;
+ clk = clk_register_fractional_divider(NULL, clk_name, parent,
+ 0, prv_base,
+ 1, 15, 16, 15, 0, NULL);
+ parent = clk_name;
+
+ clk_name = kasprintf(GFP_KERNEL, "%s-update", devname);
+ if (!clk_name) {
+ kfree(parent);
+ return -ENOMEM;
+ }
+ clk = clk_register_gate(NULL, clk_name, parent,
+ CLK_SET_RATE_PARENT | CLK_SET_RATE_GATE,
+ prv_base, 31, 0, NULL);
+ kfree(parent);
+ kfree(clk_name);
}
if (IS_ERR(clk))
return PTR_ERR(clk);
- clk_register_clkdev(clk, NULL, dev_name(&adev->dev));
+ pdata->clk = clk;
+ clk_register_clkdev(clk, NULL, devname);
return 0;
}
--
2.0.0.rc2
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