[PATCH RFC 2/3] power: mxs_power: add driver for mxs power subsystem
Stefan Wahren
stefan.wahren at i2se.com
Thu Nov 20 12:14:36 PST 2014
This patch adds a minimal driver for the Freescale i.MX23, i.MX28
power subsystem. It's required to trigger the probing of the underlying
drivers like on-chip regulators. Additionally the drivers supports
the configuration of the DC-DC clock frequency to avoid possible
interferences.
Signed-off-by: Stefan Wahren <stefan.wahren at i2se.com>
---
drivers/power/Kconfig | 8 ++
drivers/power/Makefile | 1 +
drivers/power/mxs_power.c | 226 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 235 insertions(+)
create mode 100644 drivers/power/mxs_power.c
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 0108c2a..8a3eaa4 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -43,6 +43,14 @@ config MAX8925_POWER
Say Y here to enable support for the battery charger in the Maxim
MAX8925 PMIC.
+config MXS_POWER
+ tristate "Freescale MXS power subsystem support"
+ depends on ARCH_MXS
+ help
+ Say Y here to enable support for the Freescale i.MX23/i.MX28
+ power subsystem. This is a requirement to get access to on-chip
+ regulators, battery charger and many more.
+
config WM831X_BACKUP
tristate "WM831X backup battery charger support"
depends on MFD_WM831X
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index dfa8942..91c0a62 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_GENERIC_ADC_BATTERY) += generic-adc-battery.o
obj-$(CONFIG_PDA_POWER) += pda_power.o
obj-$(CONFIG_APM_POWER) += apm_power.o
obj-$(CONFIG_MAX8925_POWER) += max8925_power.o
+obj-$(CONFIG_MXS_POWER) += mxs_power.o
obj-$(CONFIG_WM831X_BACKUP) += wm831x_backup.o
obj-$(CONFIG_WM831X_POWER) += wm831x_power.o
obj-$(CONFIG_WM8350_POWER) += wm8350_power.o
diff --git a/drivers/power/mxs_power.c b/drivers/power/mxs_power.c
new file mode 100644
index 0000000..6b68064
--- /dev/null
+++ b/drivers/power/mxs_power.c
@@ -0,0 +1,226 @@
+/*
+ * Freescale MXS power subsystem
+ *
+ * Copyright (C) 2014 Stefan Wahren
+ *
+ * Inspired by imx-bootlets
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/types.h>
+
+#define BM_POWER_CTRL_POLARITY_VBUSVALID (1 << 5)
+#define BM_POWER_CTRL_VBUSVALID_IRQ (1 << 4)
+#define BM_POWER_CTRL_ENIRQ_VBUS_VALID (1 << 3)
+
+#define HW_POWER_5VCTRL_OFFSET 0x10
+#define HW_POWER_MISC_OFFSET 0x90
+
+#define BM_POWER_5VCTRL_VBUSVALID_THRESH (7 << 8)
+#define BM_POWER_5VCTRL_PWDN_5VBRNOUT (1 << 7)
+#define BM_POWER_5VCTRL_VBUSVALID_5VDETECT (1 << 4)
+
+#define HW_POWER_5VCTRL_VBUSVALID_THRESH_4_40V (5 << 8)
+
+#define SHIFT_FREQSEL 4
+
+#define BM_POWER_MISC_FREQSEL (7 << SHIFT_FREQSEL)
+
+#define HW_POWER_MISC_FREQSEL_20000_KHZ 1
+#define HW_POWER_MISC_FREQSEL_24000_KHZ 2
+#define HW_POWER_MISC_FREQSEL_19200_KHZ 3
+
+#define HW_POWER_MISC_SEL_PLLCLK (1 << 0)
+
+static int dcdc_pll;
+module_param(dcdc_pll, int, 0);
+MODULE_PARM_DESC(dcdc_pll,
+ "DC-DC PLL frequency (kHz). Use 19200, 20000 or 24000");
+
+struct mxs_power_data {
+ void __iomem *base_addr;
+ struct power_supply dc;
+};
+
+int get_dcdc_clk_freq(struct mxs_power_data *pdata)
+{
+ void __iomem *base = pdata->base_addr;
+ int ret = -EINVAL;
+ u32 val;
+
+ val = readl(base + HW_POWER_MISC_OFFSET);
+
+ /* XTAL source */
+ if ((val & HW_POWER_MISC_SEL_PLLCLK) == 0)
+ return 24000;
+
+ switch ((val & BM_POWER_MISC_FREQSEL) >> SHIFT_FREQSEL) {
+ case HW_POWER_MISC_FREQSEL_20000_KHZ:
+ ret = 20000;
+ break;
+ case HW_POWER_MISC_FREQSEL_24000_KHZ:
+ ret = 24000;
+ break;
+ case HW_POWER_MISC_FREQSEL_19200_KHZ:
+ ret = 19200;
+ break;
+ }
+
+ return ret;
+}
+
+int set_dcdc_clk_freq(struct mxs_power_data *pdata, int kHz)
+{
+ void __iomem *misc = pdata->base_addr + HW_POWER_MISC_OFFSET;
+ u32 val;
+ int ret = 0;
+
+ val = readl(misc);
+
+ val &= ~BM_POWER_MISC_FREQSEL;
+ val &= ~HW_POWER_MISC_SEL_PLLCLK;
+
+ /* Accept only values recommend by Freescale */
+ switch (kHz) {
+ case 19200:
+ val |= HW_POWER_MISC_FREQSEL_19200_KHZ << SHIFT_FREQSEL;
+ break;
+ case 20000:
+ val |= HW_POWER_MISC_FREQSEL_20000_KHZ << SHIFT_FREQSEL;
+ break;
+ case 24000:
+ val |= HW_POWER_MISC_FREQSEL_24000_KHZ << SHIFT_FREQSEL;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ if (ret)
+ return ret;
+
+ /* First program FREQSEL */
+ writel(val, misc);
+
+ /* then set PLL as clk for DC-DC converter */
+ writel(val | HW_POWER_MISC_SEL_PLLCLK, misc);
+
+ return 0;
+}
+
+static enum power_supply_property mxs_power_dc_props[] = {
+ POWER_SUPPLY_PROP_ONLINE,
+};
+
+static int mxs_power_dc_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct mxs_power_data *data = container_of(psy,
+ struct mxs_power_data, dc);
+ int ret = 0;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_ONLINE:
+ val->intval = 1;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ return ret;
+}
+
+static const struct of_device_id of_mxs_power_match[] = {
+ { .compatible = "fsl,imx23-power" },
+ { .compatible = "fsl,imx28-power" },
+ { /* end */ }
+};
+MODULE_DEVICE_TABLE(of, of_mxs_power_match);
+
+static int mxs_power_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct resource *res;
+ struct mxs_power_data *data;
+ int ret;
+ int dcdc_clk_freq;
+
+ if (!np) {
+ dev_err(dev, "missing device tree\n");
+ return -EINVAL;
+ }
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (data == NULL)
+ return -ENOMEM;
+
+ data->dc.properties = mxs_power_dc_props;
+ data->dc.num_properties = ARRAY_SIZE(mxs_power_dc_props);
+ data->dc.get_property = mxs_power_dc_get_property;
+ data->dc.name = "dc";
+ data->dc.type = POWER_SUPPLY_TYPE_MAINS;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ data->base_addr = devm_ioremap_resource(dev, res);
+ if (IS_ERR(data->base_addr))
+ return PTR_ERR(data->base_addr);
+
+ ret = power_supply_register(dev, &data->dc);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, data);
+
+ if (dcdc_pll)
+ set_dcdc_clk_freq(data, dcdc_pll);
+
+ dcdc_clk_freq = get_dcdc_clk_freq(data);
+
+ dev_info(dev, "DCDC clock freq: %d kHz\n", dcdc_clk_freq);
+
+ return of_platform_populate(np, NULL, NULL, dev);
+}
+
+static int mxs_power_remove(struct platform_device *pdev)
+{
+ struct mxs_power_data *data = platform_get_drvdata(pdev);
+
+ of_platform_depopulate(&pdev->dev);
+ power_supply_unregister(&data->dc);
+
+ return 0;
+}
+
+static struct platform_driver mxs_power_driver = {
+ .driver = {
+ .name = "mxs_power",
+ .owner = THIS_MODULE,
+ .of_match_table = of_mxs_power_match,
+ },
+ .probe = mxs_power_probe,
+ .remove = mxs_power_remove,
+};
+
+module_platform_driver(mxs_power_driver);
+
+MODULE_AUTHOR("Stefan Wahren <stefan.wahren at i2se.com>");
+MODULE_DESCRIPTION("Freescale MXS power subsystem");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5
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