Commit b33af11d authored by Suravee Suthikulpanit's avatar Suravee Suthikulpanit Committed by Wolfram Sang

i2c: designware: Do not require clock when SSCN and FFCN are provided

The current driver uses input clock source frequency to calculate
values for [SS|FS]_[HC|LC] registers. However, when booting ACPI, we do not
currently have a good way to provide the frequency information.
Instead, we can leverage the SSCN and FFCN ACPI methods, which can be used
to directly provide these values. So, the clock information should
no longer be required during probing.

However, since clk can be invalid, additional checks must be done where
we are making use of it.
Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarSuravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Tested-by: default avatarLoc Ho <lho@apm.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent fa5b0bfa
......@@ -271,6 +271,17 @@ static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
enable ? "en" : "dis");
}
static unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev)
{
/*
* Clock is not necessary if we got LCNT/HCNT values directly from
* the platform code.
*/
if (WARN_ON_ONCE(!dev->get_clk_rate_khz))
return 0;
return dev->get_clk_rate_khz(dev);
}
/**
* i2c_dw_init() - initialize the designware i2c master hardware
* @dev: device private data
......@@ -281,7 +292,6 @@ static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
*/
int i2c_dw_init(struct dw_i2c_dev *dev)
{
u32 input_clock_khz;
u32 hcnt, lcnt;
u32 reg;
u32 sda_falling_time, scl_falling_time;
......@@ -295,8 +305,6 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
}
}
input_clock_khz = dev->get_clk_rate_khz(dev);
reg = dw_readl(dev, DW_IC_COMP_TYPE);
if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
/* Configure register endianess access */
......@@ -325,12 +333,12 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
hcnt = dev->ss_hcnt;
lcnt = dev->ss_lcnt;
} else {
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
4000, /* tHD;STA = tHIGH = 4.0 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
4700, /* tLOW = 4.7 us */
scl_falling_time,
0); /* No offset */
......@@ -344,12 +352,12 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
hcnt = dev->fs_hcnt;
lcnt = dev->fs_lcnt;
} else {
hcnt = i2c_dw_scl_hcnt(input_clock_khz,
hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
600, /* tHD;STA = tHIGH = 0.6 us */
sda_falling_time,
0, /* 0: DW default, 1: Ideal */
0); /* No offset */
lcnt = i2c_dw_scl_lcnt(input_clock_khz,
lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
1300, /* tLOW = 1.3 us */
scl_falling_time,
0); /* No offset */
......
......@@ -128,6 +128,18 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
}
#endif
static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
{
if (IS_ERR(i_dev->clk))
return PTR_ERR(i_dev->clk);
if (prepare)
return clk_prepare_enable(i_dev->clk);
clk_disable_unprepare(i_dev->clk);
return 0;
}
static int dw_i2c_plat_probe(struct platform_device *pdev)
{
struct dw_i2c_dev *dev;
......@@ -205,16 +217,13 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
dev->clk = devm_clk_get(&pdev->dev, NULL);
dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
if (IS_ERR(dev->clk))
return PTR_ERR(dev->clk);
clk_prepare_enable(dev->clk);
if (!i2c_dw_plat_prepare_clk(dev, true)) {
dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
if (!dev->sda_hold_time && ht) {
u32 ic_clk = dev->get_clk_rate_khz(dev);
dev->sda_hold_time = div_u64((u64)ic_clk * ht + 500000,
1000000);
if (!dev->sda_hold_time && ht)
dev->sda_hold_time = div_u64(
(u64)dev->get_clk_rate_khz(dev) * ht + 500000,
1000000);
}
if (!dev->tx_fifo_depth) {
......@@ -297,7 +306,7 @@ static int dw_i2c_plat_suspend(struct device *dev)
struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
i2c_dw_disable(i_dev);
clk_disable_unprepare(i_dev->clk);
i2c_dw_plat_prepare_clk(i_dev, false);
return 0;
}
......@@ -307,7 +316,7 @@ static int dw_i2c_plat_resume(struct device *dev)
struct platform_device *pdev = to_platform_device(dev);
struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
clk_prepare_enable(i_dev->clk);
i2c_dw_plat_prepare_clk(i_dev, true);
if (!i_dev->pm_runtime_disabled)
i2c_dw_init(i_dev);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment