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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>
This commit is contained in:
Bai Ping 2015-09-11 23:41:05 +08:00 committed by Rafael J. Wysocki
parent febf63cf61
commit a35fc5a33b
1 changed files with 45 additions and 5 deletions
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50
drivers/cpufreq/imx6q-cpufreq.c
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@ -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;
}