ACPI / LPSS: support for fractional divider clock
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@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index a01d4d1..d1c9b04 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -29,6 +29,7 @@
#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 @@
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 @@
.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 @@
.clk_required = true,
.prv_offset = 0x800,
.ltr_required = true,
+ .clk_divider = true,
.clk_gate = true,
.setup = lpss_uart_setup,
};
@@ -125,31 +136,21 @@
.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 @@
/* 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 },
@@ -192,8 +193,8 @@
{ "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 },
@@ -221,9 +222,11 @@
{
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();
@@ -234,7 +237,7 @@
if (dev_desc->clkdev_name) {
clk_register_clkdev(clk_data->clk, dev_desc->clkdev_name,
- dev_name(&adev->dev));
+ devname);
return 0;
}
@@ -243,6 +246,7 @@
return -ENODATA;
parent = clk_data->name;
+ prv_base = pdata->mmio_base + dev_desc->prv_offset;
if (shared_clock) {
clk = shared_clock->clk;
@@ -256,16 +260,41 @@
}
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;
}