[PATCH 2/2] cpufreq: imx6q: read OCOTP through nvmem for imx6ul/imx6ull

[Anson Huang]

On i.MX6UL/i.MX6ULL, accessing OCOTP directly is wrong because
the ocotp clock needs to be enabled first. Add support for reading
OCOTP through the nvmem API instead.

Signed-off-by: Anson Huang <anson.hu...@nxp.com>
---
 drivers/cpufreq/imx6q-cpufreq.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
index b2ff423..4ae6c74 100644
--- a/drivers/cpufreq/imx6q-cpufreq.c
+++ b/drivers/cpufreq/imx6q-cpufreq.c
@@ -12,6 +12,7 @@
 #include <linux/cpu_cooling.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/nvmem-consumer.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/pm_opp.h>
@@ -290,22 +291,11 @@ static void imx6q_opp_check_speed_grading(struct device 
*dev)
 #define OCOTP_CFG3_6ULL_SPEED_792MHZ   0x2
 #define OCOTP_CFG3_6ULL_SPEED_900MHZ   0x3
 
-static void imx6ul_opp_check_speed_grading(struct device *dev)
+static int imx6ul_opp_check_speed_grading(struct device *dev)
 {
-       struct device_node *np;
-       void __iomem *base;
+       int ret;
        u32 val;
 
-       np = of_find_compatible_node(NULL, NULL, "fsl,imx6ul-ocotp");
-       if (!np)
-               return;
-
-       base = of_iomap(np, 0);
-       if (!base) {
-               dev_err(dev, "failed to map ocotp\n");
-               goto put_node;
-       }
-
        /*
         * Speed GRADING[1:0] defines the max speed of ARM:
         * 2b'00: Reserved;
@@ -314,7 +304,10 @@ static void imx6ul_opp_check_speed_grading(struct device 
*dev)
         * 2b'11: 900000000Hz on i.MX6ULL only;
         * We need to set the max speed of ARM according to fuse map.
         */
-       val = readl_relaxed(base + OCOTP_CFG3);
+       ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
+       if (ret)
+               return ret;
+
        val >>= OCOTP_CFG3_SPEED_SHIFT;
        val &= 0x3;
 
@@ -334,9 +327,7 @@ static void imx6ul_opp_check_speed_grading(struct device 
*dev)
                                dev_warn(dev, "failed to disable 900MHz OPP\n");
        }
 
-       iounmap(base);
-put_node:
-       of_node_put(np);
+       return ret;
 }
 
 static int imx6q_cpufreq_probe(struct platform_device *pdev)
@@ -394,10 +385,18 @@ static int imx6q_cpufreq_probe(struct platform_device 
*pdev)
        }
 
        if (of_machine_is_compatible("fsl,imx6ul") ||
-           of_machine_is_compatible("fsl,imx6ull"))
-               imx6ul_opp_check_speed_grading(cpu_dev);
-       else
+           of_machine_is_compatible("fsl,imx6ull")) {
+               ret = imx6ul_opp_check_speed_grading(cpu_dev);
+               if (ret == -EPROBE_DEFER)
+                       return ret;
+               if (ret) {
+                       dev_err(cpu_dev, "failed to read from nvmem: %d\n",
+                               ret);
+                       return ret;
+               }
+       } else {
                imx6q_opp_check_speed_grading(cpu_dev);
+       }
 
        /* Because we have added the OPPs here, we must free them */
        free_opp = true;
-- 
2.7.4