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Subject[PATCH v4 1/2] i2c: qup: add ACPI support
Date
From: Naveen Kaje <nkaje@codeaurora.org>

Add support to get the device parameters from ACPI. Assume
that the clocks are managed by firmware.

Signed-off-by: Naveen Kaje <nkaje@codeaurora.org>
Signed-off-by: Austin Christ <austinwc@codeaurora.org>
Reviewed-by: sricharan@codeaurora.org
---
drivers/i2c/busses/i2c-qup.c | 59 ++++++++++++++++++++++++++++++++------------
1 file changed, 43 insertions(+), 16 deletions(-)

Changes:
- v4:
- remove warning for fall back to default clock frequency
- v3:
- clean up unused variable
- v2:
- clean up redundant checks and variables

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index dddd4da..0f23d58 100644
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -29,6 +29,7 @@
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/scatterlist.h>
+#include <linux/acpi.h>

/* QUP Registers */
#define QUP_CONFIG 0x000
@@ -132,6 +133,10 @@
/* Max timeout in ms for 32k bytes */
#define TOUT_MAX 300

+/* Default values. Use these if FW query fails */
+#define DEFAULT_CLK_FREQ 100000
+#define DEFAULT_SRC_CLK 20000000
+
struct qup_i2c_block {
int count;
int pos;
@@ -1354,14 +1359,13 @@ static void qup_i2c_disable_clocks(struct qup_i2c_dev *qup)
static int qup_i2c_probe(struct platform_device *pdev)
{
static const int blk_sizes[] = {4, 16, 32};
- struct device_node *node = pdev->dev.of_node;
struct qup_i2c_dev *qup;
unsigned long one_bit_t;
struct resource *res;
u32 io_mode, hw_ver, size;
int ret, fs_div, hs_div;
- int src_clk_freq;
- u32 clk_freq = 100000;
+ u32 src_clk_freq = 0;
+ u32 clk_freq = DEFAULT_CLK_FREQ;
int blocks;

qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL);
@@ -1372,7 +1376,11 @@ static int qup_i2c_probe(struct platform_device *pdev)
init_completion(&qup->xfer);
platform_set_drvdata(pdev, qup);

- of_property_read_u32(node, "clock-frequency", &clk_freq);
+ ret = device_property_read_u32(qup->dev, "clock-frequency", &clk_freq);
+ if (ret) {
+ dev_notice(qup->dev, "using default clock-frequency %d",
+ DEFAULT_CLK_FREQ);
+ }

if (of_device_is_compatible(pdev->dev.of_node, "qcom,i2c-qup-v1.1.1")) {
qup->adap.algo = &qup_i2c_algo;
@@ -1454,20 +1462,31 @@ nodma:
return qup->irq;
}

- qup->clk = devm_clk_get(qup->dev, "core");
- if (IS_ERR(qup->clk)) {
- dev_err(qup->dev, "Could not get core clock\n");
- return PTR_ERR(qup->clk);
- }
+ if (ACPI_HANDLE(qup->dev)) {
+ ret = device_property_read_u32(qup->dev,
+ "src-clock-hz", &src_clk_freq);
+ if (ret) {
+ dev_warn(qup->dev, "using default src-clock-hz %d",
+ DEFAULT_SRC_CLK);
+ src_clk_freq = DEFAULT_SRC_CLK;
+ }
+ ACPI_COMPANION_SET(&qup->adap.dev, ACPI_COMPANION(qup->dev));
+ } else {
+ qup->clk = devm_clk_get(qup->dev, "core");
+ if (IS_ERR(qup->clk)) {
+ dev_err(qup->dev, "Could not get core clock\n");
+ return PTR_ERR(qup->clk);
+ }

- qup->pclk = devm_clk_get(qup->dev, "iface");
- if (IS_ERR(qup->pclk)) {
- dev_err(qup->dev, "Could not get iface clock\n");
- return PTR_ERR(qup->pclk);
+ qup->pclk = devm_clk_get(qup->dev, "iface");
+ if (IS_ERR(qup->pclk)) {
+ dev_err(qup->dev, "Could not get iface clock\n");
+ return PTR_ERR(qup->pclk);
+ }
+ qup_i2c_enable_clocks(qup);
+ src_clk_freq = clk_get_rate(qup->clk);
}

- qup_i2c_enable_clocks(qup);
-
/*
* Bootloaders might leave a pending interrupt on certain QUP's,
* so we reset the core before registering for interrupts.
@@ -1514,7 +1533,6 @@ nodma:
size = QUP_INPUT_FIFO_SIZE(io_mode);
qup->in_fifo_sz = qup->in_blk_sz * (2 << size);

- src_clk_freq = clk_get_rate(qup->clk);
fs_div = ((src_clk_freq / clk_freq) / 2) - 3;
hs_div = 3;
qup->clk_ctl = (hs_div << 8) | (fs_div & 0xff);
@@ -1639,6 +1657,14 @@ static const struct of_device_id qup_i2c_dt_match[] = {
};
MODULE_DEVICE_TABLE(of, qup_i2c_dt_match);

+#if IS_ENABLED(CONFIG_ACPI)
+static const struct acpi_device_id qup_i2c_acpi_match[] = {
+ { "QCOM8010"},
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, qup_i2c_acpi_ids);
+#endif
+
static struct platform_driver qup_i2c_driver = {
.probe = qup_i2c_probe,
.remove = qup_i2c_remove,
@@ -1646,6 +1672,7 @@ static struct platform_driver qup_i2c_driver = {
.name = "i2c_qup",
.pm = &qup_i2c_qup_pm_ops,
.of_match_table = qup_i2c_dt_match,
+ .acpi_match_table = ACPI_PTR(qup_i2c_acpi_match),
},
};

--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
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