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authorBai Ping <b51503@freescale.com>2015-09-11 23:41:05 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-09-26 03:02:11 +0200
commita35fc5a33b62a6c658b8ffe7544c966c1776d128 (patch)
tree14b6d68b27e3d3019da53a7915879473d44484c0
parentfebf63cf616083e9a4ee05e2c28163b074890f36 (diff)
downloadleg-kernel-a35fc5a33b62a6c658b8ffe7544c966c1776d128.tar.gz
cpufreq: imx: update the clock switch flow to support imx6ul
For i.MX6UL, the clock switch flow is slightly different from other i.MX6 SOCs. It has a 'secondary_sel' clk that will be used when the CPU freq is higher than 396MHz. So the clock switch flow in 'set_target' callback need to update to support i.MX6UL in the common i.MX6 SOC cpufreq driver. Signed-off-by: Bai Ping <b51503@freescale.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/cpufreq/imx6q-cpufreq.c50
1 files changed, 45 insertions, 5 deletions
diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
index 380a90d3c57e..9b4a7bd04dea 100644
--- a/drivers/cpufreq/imx6q-cpufreq.c
+++ b/drivers/cpufreq/imx6q-cpufreq.c
@@ -30,6 +30,10 @@ static struct clk *pll1_sw_clk;
static struct clk *step_clk;
static struct clk *pll2_pfd2_396m_clk;
+/* clk used by i.MX6UL */
+static struct clk *pll2_bus_clk;
+static struct clk *secondary_sel_clk;
+
static struct device *cpu_dev;
static bool free_opp;
static struct cpufreq_frequency_table *freq_table;
@@ -91,16 +95,36 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
* The setpoints are selected per PLL/PDF frequencies, so we need to
* reprogram PLL for frequency scaling. The procedure of reprogramming
* PLL1 is as below.
- *
+ * For i.MX6UL, it has a secondary clk mux, the cpu frequency change
+ * flow is slightly different from other i.MX6 OSC.
+ * The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
* - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
* - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
* - Disable pll2_pfd2_396m_clk
*/
- clk_set_parent(step_clk, pll2_pfd2_396m_clk);
- clk_set_parent(pll1_sw_clk, step_clk);
- if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
- clk_set_rate(pll1_sys_clk, new_freq * 1000);
+ if (of_machine_is_compatible("fsl,imx6ul")) {
+ /*
+ * When changing pll1_sw_clk's parent to pll1_sys_clk,
+ * CPU may run at higher than 528MHz, this will lead to
+ * the system unstable if the voltage is lower than the
+ * voltage of 528MHz, so lower the CPU frequency to one
+ * half before changing CPU frequency.
+ */
+ clk_set_rate(arm_clk, (old_freq >> 1) * 1000);
clk_set_parent(pll1_sw_clk, pll1_sys_clk);
+ if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk))
+ clk_set_parent(secondary_sel_clk, pll2_bus_clk);
+ else
+ clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk);
+ clk_set_parent(step_clk, secondary_sel_clk);
+ clk_set_parent(pll1_sw_clk, step_clk);
+ } else {
+ clk_set_parent(step_clk, pll2_pfd2_396m_clk);
+ clk_set_parent(pll1_sw_clk, step_clk);
+ if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
+ clk_set_rate(pll1_sys_clk, new_freq * 1000);
+ clk_set_parent(pll1_sw_clk, pll1_sys_clk);
+ }
}
/* Ensure the arm clock divider is what we expect */
@@ -186,6 +210,16 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev)
goto put_clk;
}
+ if (of_machine_is_compatible("fsl,imx6ul")) {
+ pll2_bus_clk = clk_get(cpu_dev, "pll2_bus");
+ secondary_sel_clk = clk_get(cpu_dev, "secondary_sel");
+ if (IS_ERR(pll2_bus_clk) || IS_ERR(secondary_sel_clk)) {
+ dev_err(cpu_dev, "failed to get clocks specific to imx6ul\n");
+ ret = -ENOENT;
+ goto put_clk;
+ }
+ }
+
arm_reg = regulator_get(cpu_dev, "arm");
pu_reg = regulator_get_optional(cpu_dev, "pu");
soc_reg = regulator_get(cpu_dev, "soc");
@@ -331,6 +365,10 @@ put_clk:
clk_put(step_clk);
if (!IS_ERR(pll2_pfd2_396m_clk))
clk_put(pll2_pfd2_396m_clk);
+ if (!IS_ERR(pll2_bus_clk))
+ clk_put(pll2_bus_clk);
+ if (!IS_ERR(secondary_sel_clk))
+ clk_put(secondary_sel_clk);
of_node_put(np);
return ret;
}
@@ -350,6 +388,8 @@ static int imx6q_cpufreq_remove(struct platform_device *pdev)
clk_put(pll1_sw_clk);
clk_put(step_clk);
clk_put(pll2_pfd2_396m_clk);
+ clk_put(pll2_bus_clk);
+ clk_put(secondary_sel_clk);
return 0;
}