Re: [PATCH] soc: qcom: Add support for SAW2 regulators

[Lina Iyer <lina.iyer@linaro.org>]

On Fri, Dec 18 2015 at 09:15 -0700, Georgi Djakov wrote:
>The SAW2 (Subsystem Power Manager and Adaptive Voltage Scaling Wrapper)
>is part of the SPM subsystem. It is a hardware block found on some of the
>Qualcomm chipsets, which regulates the power to the CPU cores. Add some
>basic support for it, so that we can do dynamic voltage scaling.
>
>Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
>---
> drivers/soc/qcom/spm.c |  149 +++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 148 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/soc/qcom/spm.c b/drivers/soc/qcom/spm.c
>index b04b05a0904e..03fcee4b85d9 100644
>--- a/drivers/soc/qcom/spm.c
>+++ b/drivers/soc/qcom/spm.c
>@@ -20,11 +20,14 @@
> #include <linux/of.h>
> #include <linux/of_address.h>
> #include <linux/of_device.h>
>+#include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/platform_device.h>
> #include <linux/cpuidle.h>
> #include <linux/cpu_pm.h>
> #include <linux/qcom_scm.h>
>+#include <linux/regulator/driver.h>
>+#include <linux/regulator/of_regulator.h>
>
> #include <asm/cpuidle.h>
> #include <asm/proc-fns.h>
>@@ -51,6 +54,8 @@ enum spm_reg {
> 	SPM_REG_PMIC_DLY,
> 	SPM_REG_PMIC_DATA_0,
> 	SPM_REG_PMIC_DATA_1,
>+	SPM_REG_RST,
>+	SPM_REG_STS_1,
> 	SPM_REG_VCTL,
> 	SPM_REG_SEQ_ENTRY,
> 	SPM_REG_SPM_STS,
>@@ -68,9 +73,22 @@ struct spm_reg_data {
> 	u8 start_index[PM_SLEEP_MODE_NR];
> };
>
>+struct spm_vlevel_data {
>+	struct spm_driver_data *drv;
>+	unsigned selector;
>+};
>+
>+struct saw2_vreg {
>+	struct regulator_desc	rdesc;
>+	struct regulator_dev	*rdev;
>+	struct spm_driver_data	*drv;
>+	u32			selector;
>+};
>+
> struct spm_driver_data {
> 	void __iomem *reg_base;
> 	const struct spm_reg_data *reg_data;
>+	struct saw2_vreg *vreg;
> };
>
> static const u8 spm_reg_offset_v2_1[SPM_REG_NR] = {
>@@ -94,10 +112,13 @@ static const struct spm_reg_data spm_reg_8974_8084_cpu  = {
>
> static const u8 spm_reg_offset_v1_1[SPM_REG_NR] = {
> 	[SPM_REG_CFG]		= 0x08,
>+	[SPM_REG_STS_1]		= 0x10,
>+	[SPM_REG_VCTL]		= 0x14,
> 	[SPM_REG_SPM_CTL]	= 0x20,
> 	[SPM_REG_PMIC_DLY]	= 0x24,
> 	[SPM_REG_PMIC_DATA_0]	= 0x28,
> 	[SPM_REG_PMIC_DATA_1]	= 0x2C,
>+	[SPM_REG_RST]		= 0x30,
> 	[SPM_REG_SEQ_ENTRY]	= 0x80,
> };
>
>@@ -282,6 +303,127 @@ static struct cpuidle_ops qcom_cpuidle_ops __initdata = {
> CPUIDLE_METHOD_OF_DECLARE(qcom_idle_v1, "qcom,kpss-acc-v1", &qcom_cpuidle_ops);
> CPUIDLE_METHOD_OF_DECLARE(qcom_idle_v2, "qcom,kpss-acc-v2", &qcom_cpuidle_ops);
>
>+static int saw2_regulator_get_voltage(struct regulator_dev *rdev)
>+{
>+	struct spm_driver_data *drv = rdev_get_drvdata(rdev);
>+
>+	return regulator_list_voltage_linear_range(rdev, drv->vreg->selector);
>+}
>+
>+static void spm_smp_set_vdd(void *data)
>+{
>+	struct spm_vlevel_data *vdata = (struct spm_vlevel_data *)data;
>+	struct spm_driver_data *drv = vdata->drv;
>+	struct saw2_vreg *vreg = drv->vreg;
>+	u32 sel = vdata->selector;
>+	u32 val, new_val;
>+	u32 vctl, data0, data1;
>+	int timeout_us = 50;
>+
>+	if (vreg->selector == sel)
>+		return;
>+
>+	vctl = spm_register_read(drv, SPM_REG_VCTL);
>+	data0 = spm_register_read(drv, SPM_REG_PMIC_DATA_0);
>+	data1 = spm_register_read(drv, SPM_REG_PMIC_DATA_1);
>+
>+	/* select the band */
>+	val = 0x80 | sel;
>+
>+	vctl &= ~0xff;
>+	vctl |= val;
>+
>+	data0 &= ~0xff;
>+	data0 |= val;
>+
>+	data1 &= ~0x3f;
>+	data1 |= val & 0x3f;
>+	data1 &= ~0x3f0000;
>+	data1 |= (val & 0x3f) << 16;
>+
>+	spm_register_write(drv, SPM_REG_RST, 1);
>+	spm_register_write(drv, SPM_REG_VCTL, vctl);
>+	spm_register_write(drv, SPM_REG_PMIC_DATA_0, data0);
>+	spm_register_write(drv, SPM_REG_PMIC_DATA_1, data1);
>+
>+	do {
>+		new_val = spm_register_read(drv, SPM_REG_STS_1) & 0xff;
>+		if (new_val == val)
>+			break;
>+		udelay(1);
>+	} while (--timeout_us);
>+
>+	if (!timeout_us) {
>+		pr_err("%s: Voltage not changed: %#x\n", __func__, new_val);
>+		return;
>+	}
>+
>+	if (sel > vreg->selector) {
>+		/* PMIC internal slew rate is 1250 uV per us */
>+		udelay((sel - vreg->selector) * 10);
>+	}
>+
>+	vreg->selector = sel;
>+}
>+
>+static int saw2_regulator_set_voltage_sel(struct regulator_dev *rdev,
>+					  unsigned selector)
>+{
>+	struct spm_driver_data *drv = rdev_get_drvdata(rdev);
>+	struct spm_vlevel_data data;
>+	int cpu = rdev_get_id(rdev);
>+
>+	data.drv = drv;
>+	data.selector = selector;
>+
>+	return smp_call_function_single(cpu, spm_smp_set_vdd, &data, true);
>+}
>+
>+static struct regulator_ops saw2_regulator_ops = {
>+	.list_voltage = regulator_list_voltage_linear_range,
>+	.set_voltage_sel = saw2_regulator_set_voltage_sel,
>+	.get_voltage = saw2_regulator_get_voltage,
>+};
>+
>+static struct regulator_desc saw2_regulator = {
>+	.owner = THIS_MODULE,
>+	.type = REGULATOR_VOLTAGE,
>+	.ops  = &saw2_regulator_ops,
>+	.linear_ranges = (struct regulator_linear_range[]) {
>+		REGULATOR_LINEAR_RANGE(700000, 0, 56, 12500),
>+	},
>+	.n_linear_ranges = 1,
>+	.n_voltages = 57,
>+};
>+
>+static int register_saw2_regulator(struct spm_driver_data *drv,
>+				   struct platform_device *pdev, int cpu)
>+{
>+	struct device_node *np = pdev->dev.of_node;
>+	struct saw2_vreg *vreg;
>+	struct regulator_config config = { };
>+
>+	vreg = devm_kzalloc(&pdev->dev, sizeof(*vreg), GFP_KERNEL);
>+	if (!vreg)
>+		return -ENOMEM;
>+
>+	drv->vreg = vreg;
>+	config.driver_data = drv;
>+	config.dev = &pdev->dev;
>+	config.of_node = np;
>+
>+	vreg->rdesc = saw2_regulator;
>+	vreg->rdesc.id = cpu;
>+	vreg->rdesc.name = of_get_property(np, "regulator-name", NULL);
>+	config.init_data = of_get_regulator_init_data(&pdev->dev,
>+						      pdev->dev.of_node,
>+						      &vreg->rdesc);
>+
>+	vreg->rdev = devm_regulator_register(&pdev->dev, &vreg->rdesc, &config);
>+
>+	return PTR_ERR_OR_ZERO(vreg->rdev);
>+}
>+
> static struct spm_driver_data *spm_get_drv(struct platform_device *pdev,
> 		int *spm_cpu)
> {
>@@ -327,7 +469,7 @@ static int spm_dev_probe(struct platform_device *pdev)
> 	struct resource *res;
> 	const struct of_device_id *match_id;
> 	void __iomem *addr;
>-	int cpu;
>+	int cpu, ret;
>
> 	drv = spm_get_drv(pdev, &cpu);
> 	if (!drv)
>@@ -368,6 +510,11 @@ static int spm_dev_probe(struct platform_device *pdev)
>
> 	per_cpu(cpu_spm_drv, cpu) = drv;
>
>+	ret = register_saw2_regulator(drv, pdev, cpu);
>
Not all SAWs are regulators. On 8084, only the L2 SAW is a regulator.
You may want to parse the device node to see if it has a 'regulator'
property and then initialize the regulator aspect of the SAW. L2 SAW
nodes are not present in the upstream kernel. You can find a patch that
adds cache SPM here in my WIP series at [1].

Sorry, if I have missed this point in the code.

Thanks,
Lina

[1].
https://git.linaro.org/people/lina.iyer/linux-next.git/shortlog/refs/heads/genpd-psci-8084

>+	if (ret)
>+		dev_err(&pdev->dev, "error registering SAW2 regulator: %d\n",
>+			ret);
>+
> 	return 0;
> }
>