The current kernel driver does not consider I2C_IPGCLK_SEL (424 bit
of RCW) in deciding i2c_clk_rate in function i2c_imx_set_clk()
{ 0 Platform clock/4, 1 Platform clock/2}.
When using ls1046a SoC, this populates incorrect value in IBFD register
if I2C_IPGCLK_SEL = 0, which generates half of the desired Clock.
Therefore, if ls1046a SoC is used, we need to set the i2c clock
according to the corresponding RCW.
Signed-off-by: Sumit Batra <sumit.batra@xxxxxxx>
Signed-off-by: Chuanhua Han <chuanhua.han@xxxxxxx>
---
drivers/i2c/busses/i2c-imx.c | 64 ++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 422f1a445b55..7186cf3c7d24 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -45,6 +45,8 @@
#include <linux/pm_runtime.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/fsl/guts.h>
+#include <linux/sys_soc.h>
/* This will be the driver name the kernel reports */
#define DRIVER_NAME "imx-i2c"
@@ -109,6 +111,21 @@
#define I2C_PM_TIMEOUT 10 /* ms */
+/* 14-1 Since array index starts from 0 */
+#define RCW_I2C_IPGCLK_WORD (14 - 1)
+/*
+ * Set mask for RCW 424th bit, reading from DCFG_CCSR RCW Status Registers
+ * Since this register in RM depicted as big endian,
+ * so consider 31st bit as LSB for creating the mask.
+ */
+#define RCW_I2C_IPGCLK_MASK 0x800000
+int i2c_ipgclk_sel = 1;
+
+static const struct soc_device_attribute ls1046a_soc[] = {
+ {.family = "QorIQ LS1046A"},
+ { /* sentinel */ }
+};
+
/*
* sorted list of clock divider, register value pairs
* taken from table 26-5, p.26-9, Freescale i.MX
@@ -304,6 +321,11 @@ static const struct platform_device_id imx_i2c_devtype[] = {
};
MODULE_DEVICE_TABLE(platform, imx_i2c_devtype);
+static const struct of_device_id guts_device_ids[] = {
+ { .compatible = "fsl,qoriq-device-config", },
+ {}
+};
+
static const struct of_device_id i2c_imx_dt_ids[] = {
{ .compatible = "fsl,imx1-i2c", .data = &imx1_i2c_hwdata, },
{ .compatible = "fsl,imx21-i2c", .data = &imx21_i2c_hwdata, },
@@ -533,6 +555,9 @@ static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
unsigned int div;
int i;
+ if (!i2c_ipgclk_sel)
+ i2c_clk_rate = i2c_clk_rate / 2;
+
/* Divider value calculation */
if (i2c_imx->cur_clk == i2c_clk_rate)
return;
@@ -551,6 +576,10 @@ static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
/* Store divider value */
i2c_imx->ifdr = i2c_clk_div[i].val;
+ pr_alert("[%s] CLK Rate=%u Bitrate =%u Div =%u Value =%d\n",
+ __func__, i2c_clk_rate, i2c_imx->bitrate,
+ div, i2c_clk_div[i].val);
+
/*
* There dummy delay is calculated.
* It should be about one I2C clock period long.
@@ -1116,6 +1145,9 @@ static int i2c_imx_probe(struct platform_device *pdev)
int irq, ret;
dma_addr_t phy_addr;
u32 mul_value;
+ struct device_node *guts_node;
+ static struct ccsr_guts __iomem *guts_regs;
+ u32 rcw_reg;
dev_dbg(&pdev->dev, "<%s>\n", __func__);
@@ -1135,6 +1167,38 @@ static int i2c_imx_probe(struct platform_device *pdev)
if (!i2c_imx)
return -ENOMEM;
+ if (soc_device_match(ls1046a_soc)) {
+ /*
+ * Make device node for GUTS/DCFG (global utilities block)
+ * to read RCW.
+ */
+ guts_node = of_find_matching_node(NULL, guts_device_ids);
+ if (!guts_node) {
+ dev_err(&pdev->dev, "Could not find GUTS node\n");
+ return -ENODEV;
+ }
+ /*
+ * Memory (IO) MAP the DCFG registers(for RCW) to
+ * be used in kernel virtual address space.
+ */
+ guts_regs = of_iomap(guts_node, 0);
+ of_node_put(guts_node);
+ if (!guts_regs) {
+ dev_err(&pdev->dev, "IOREMAP of GUTS node failed\n");
+ return -ENOMEM;
+ }
+ /* Read rcw bit 424 (starting from 0) */
+ rcw_reg = ioread32be(&guts_regs->rcwsr[RCW_I2C_IPGCLK_WORD]);
+ pr_alert("RCW REG[%d]=0x%x\n", RCW_I2C_IPGCLK_WORD, rcw_reg);
+ if (rcw_reg & RCW_I2C_IPGCLK_MASK) {
+ pr_alert("Div by 2 Case Detected in RCW\n");
+ i2c_ipgclk_sel = 1;
+ } else {
+ pr_alert("Div by 4 Case Detected in RCW\n");
+ i2c_ipgclk_sel = 0;
+ }
+ }
+
if (of_id) {
i2c_imx->hwdata = of_id->data;
ret = of_property_read_u32(pdev->dev.of_node,
--
2.17.1
