[PATCH V2] cpufreq: imx-cpufreq-dt: support i.MX7ULP

From: peng . fan
Date: Tue Apr 28 2020 - 03:30:01 EST


From: Peng Fan <peng.fan@xxxxxxx>

i.MX7ULP's ARM core clock design is totally different compared
with i.MX7D/8M SoCs which supported by imx-cpufreq-dt. It needs
get_intermediate and target_intermedate to configure clk MUX ready,
before let OPP configure ARM core clk.
|---FIRC
|------RUN---...---SCS(MUX2) --------|
ARM --(MUX1) |---SPLL_PFD0(CLK_SET_RATE_GATE)
|------HSRUN--...--HSRUN_SCS(MUX3)---|
|---SRIC

FIRC is step clk, SPLL_PFD0 is the normal clk driving ARM core.
MUX2 and MUX3 share same inputs. So if MUX2/MUX3 both sources from
SPLL_PFD0, both MUXes will lose input when configure SPLL_PFD0.
So the target_intermediate will configure MUX2/MUX3 to FIRC, to avoid
ARM core lose clk when configure SPLL_PFD0.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---

V2:
Fix boot break. Tested on i.MX8MN DDR4 EVK.

drivers/cpufreq/imx-cpufreq-dt.c | 84 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 82 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/imx-cpufreq-dt.c b/drivers/cpufreq/imx-cpufreq-dt.c
index de206d2745fe..3fe9125156b4 100644
--- a/drivers/cpufreq/imx-cpufreq-dt.c
+++ b/drivers/cpufreq/imx-cpufreq-dt.c
@@ -3,7 +3,9 @@
* Copyright 2019 NXP
*/

+#include <linux/clk.h>
#include <linux/cpu.h>
+#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
@@ -12,8 +14,11 @@
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
+#include <linux/regulator/consumer.h>
#include <linux/slab.h>

+#include "cpufreq-dt.h"
+
#define OCOTP_CFG3_SPEED_GRADE_SHIFT 8
#define OCOTP_CFG3_SPEED_GRADE_MASK (0x3 << 8)
#define IMX8MN_OCOTP_CFG3_SPEED_GRADE_MASK (0xf << 8)
@@ -22,20 +27,92 @@
#define IMX8MP_OCOTP_CFG3_MKT_SEGMENT_SHIFT 5
#define IMX8MP_OCOTP_CFG3_MKT_SEGMENT_MASK (0x3 << 5)

+#define IMX7ULP_MAX_RUN_FREQ 528000
+
/* cpufreq-dt device registered by imx-cpufreq-dt */
static struct platform_device *cpufreq_dt_pdev;
static struct opp_table *cpufreq_opp_table;
+static struct device *cpu_dev;
+
+enum IMX7ULP_CPUFREQ_CLKS {
+ ARM,
+ CORE,
+ SCS_SEL,
+ HSRUN_CORE,
+ HSRUN_SCS_SEL,
+ FIRC,
+};
+
+static struct clk_bulk_data imx7ulp_clks[] = {
+ { .id = "arm" },
+ { .id = "core" },
+ { .id = "scs_sel" },
+ { .id = "hsrun_core" },
+ { .id = "hsrun_scs_sel" },
+ { .id = "firc" },
+};
+
+static unsigned int imx7ulp_get_intermediate(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ return clk_get_rate(imx7ulp_clks[FIRC].clk);
+}
+
+static int imx7ulp_target_intermediate(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ unsigned int newfreq = policy->freq_table[index].frequency;
+
+ clk_set_parent(imx7ulp_clks[SCS_SEL].clk, imx7ulp_clks[FIRC].clk);
+ clk_set_parent(imx7ulp_clks[HSRUN_SCS_SEL].clk, imx7ulp_clks[FIRC].clk);
+
+ if (newfreq > IMX7ULP_MAX_RUN_FREQ)
+ clk_set_parent(imx7ulp_clks[ARM].clk,
+ imx7ulp_clks[HSRUN_CORE].clk);
+ else
+ clk_set_parent(imx7ulp_clks[ARM].clk, imx7ulp_clks[CORE].clk);
+
+ return 0;
+}
+
+static struct cpufreq_dt_platform_data imx7ulp_data = {
+ .target_intermediate = imx7ulp_target_intermediate,
+ .get_intermediate = imx7ulp_get_intermediate,
+};

static int imx_cpufreq_dt_probe(struct platform_device *pdev)
{
- struct device *cpu_dev = get_cpu_device(0);
+ struct platform_device *dt_pdev;
u32 cell_value, supported_hw[2];
int speed_grade, mkt_segment;
int ret;

+ cpu_dev = get_cpu_device(0);
+
if (!of_find_property(cpu_dev->of_node, "cpu-supply", NULL))
return -ENODEV;

+ if (of_machine_is_compatible("fsl,imx7ulp")) {
+ ret = clk_bulk_get(cpu_dev, ARRAY_SIZE(imx7ulp_clks),
+ imx7ulp_clks);
+ if (ret)
+ return ret;
+
+ dt_pdev = platform_device_register_data(NULL, "cpufreq-dt",
+ -1, &imx7ulp_data,
+ sizeof(imx7ulp_data));
+ if (IS_ERR(dt_pdev)) {
+ clk_bulk_put(ARRAY_SIZE(imx7ulp_clks), imx7ulp_clks);
+ ret = PTR_ERR(dt_pdev);
+ dev_err(&pdev->dev, "Failed to register cpufreq-dt: %d\n", ret);
+ return ret;
+ }
+
+ cpufreq_dt_pdev = dt_pdev;
+
+ return 0;
+ }
+
ret = nvmem_cell_read_u32(cpu_dev, "speed_grade", &cell_value);
if (ret)
return ret;
@@ -98,7 +175,10 @@ static int imx_cpufreq_dt_probe(struct platform_device *pdev)
static int imx_cpufreq_dt_remove(struct platform_device *pdev)
{
platform_device_unregister(cpufreq_dt_pdev);
- dev_pm_opp_put_supported_hw(cpufreq_opp_table);
+ if (!of_machine_is_compatible("fsl,imx7ulp"))
+ dev_pm_opp_put_supported_hw(cpufreq_opp_table);
+ else
+ clk_bulk_put(ARRAY_SIZE(imx7ulp_clks), imx7ulp_clks);

return 0;
}
--
2.16.4