[PATCH v2] pwm_lpss: Add support for PCI devices

From: Chew Chiau Ee
Date: Wed Apr 16 2014 - 06:16:26 EST


From: Alan Cox <alan@xxxxxxxxxxxxxxx>

Not all systems enumerate the PWM devices via ACPI. They can also be exposed
via the PCI interface.

Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@xxxxxxxxx>
---
drivers/pwm/pwm-lpss.c | 159 ++++++++++++++++++++++++++++++++++++++---------
1 files changed, 128 insertions(+), 31 deletions(-)

diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 449e372..aa8af08 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -6,6 +6,7 @@
* Author: Chew Kean Ho <kean.ho.chew@xxxxxxxxx>
* Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@xxxxxxxxx>
* Author: Chew Chiau Ee <chiau.ee.chew@xxxxxxxxx>
+ * Author: Alan Cox <alan@xxxxxxxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -19,6 +20,9 @@
#include <linux/module.h>
#include <linux/pwm.h>
#include <linux/platform_device.h>
+#include <linux/pci.h>
+
+static int pci_drv, plat_drv; /* So we know which drivers registered */

#define PWM 0x00000000
#define PWM_ENABLE BIT(31)
@@ -34,6 +38,15 @@ struct pwm_lpss_chip {
struct pwm_chip chip;
void __iomem *regs;
struct clk *clk;
+ unsigned long clk_rate;
+};
+
+struct pwm_lpss_boardinfo {
+ unsigned long clk_rate;
+};
+
+static const struct pwm_lpss_boardinfo byt_info = {
+ 25000000
};

static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
@@ -55,7 +68,7 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
/* The equation is: base_unit = ((freq / c) * 65536) + correction */
base_unit = freq * 65536;

- c = clk_get_rate(lpwm->clk);
+ c = lpwm->clk_rate;
if (!c)
return -EINVAL;

@@ -113,52 +126,47 @@ static const struct pwm_ops pwm_lpss_ops = {
.owner = THIS_MODULE,
};

-static const struct acpi_device_id pwm_lpss_acpi_match[] = {
- { "80860F09", 0 },
- { },
-};
-MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
-
-static int pwm_lpss_probe(struct platform_device *pdev)
+static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
+ struct resource *r, struct pwm_lpss_boardinfo *info)
{
struct pwm_lpss_chip *lpwm;
- struct resource *r;
int ret;

- lpwm = devm_kzalloc(&pdev->dev, sizeof(*lpwm), GFP_KERNEL);
+ lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
if (!lpwm)
- return -ENOMEM;
-
- r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ return ERR_PTR(-ENOMEM);

- lpwm->regs = devm_ioremap_resource(&pdev->dev, r);
+ lpwm->regs = devm_ioremap_resource(dev, r);
if (IS_ERR(lpwm->regs))
- return PTR_ERR(lpwm->regs);
-
- lpwm->clk = devm_clk_get(&pdev->dev, NULL);
- if (IS_ERR(lpwm->clk)) {
- dev_err(&pdev->dev, "failed to get PWM clock\n");
- return PTR_ERR(lpwm->clk);
+ return lpwm->regs;
+
+ if (info) {
+ lpwm->clk_rate = info->clk_rate;
+ } else {
+ lpwm->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(lpwm->clk)) {
+ dev_err(dev, "failed to get PWM clock\n");
+ return ERR_CAST(lpwm->clk);
+ }
+ lpwm->clk_rate = clk_get_rate(lpwm->clk);
}

- lpwm->chip.dev = &pdev->dev;
+ lpwm->chip.dev = dev;
lpwm->chip.ops = &pwm_lpss_ops;
lpwm->chip.base = -1;
lpwm->chip.npwm = 1;

ret = pwmchip_add(&lpwm->chip);
if (ret) {
- dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
- return ret;
+ dev_err(dev, "failed to add PWM chip: %d\n", ret);
+ return ERR_PTR(ret);
}

- platform_set_drvdata(pdev, lpwm);
- return 0;
+ return lpwm;
}

-static int pwm_lpss_remove(struct platform_device *pdev)
+static int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
{
- struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
u32 ctrl;

ctrl = readl(lpwm->regs + PWM);
@@ -167,15 +175,104 @@ static int pwm_lpss_remove(struct platform_device *pdev)
return pwmchip_remove(&lpwm->chip);
}

-static struct platform_driver pwm_lpss_driver = {
+static int pwm_lpss_probe_pci(struct pci_dev *pdev,
+ const struct pci_device_id *id)
+{
+ struct pwm_lpss_boardinfo *info;
+ struct pwm_lpss_chip *lpwm;
+ int err;
+
+ err = pci_enable_device(pdev);
+ if (err < 0)
+ return err;
+
+ info = (struct pwm_lpss_boardinfo *)id->driver_data;
+ lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
+ if (IS_ERR(lpwm))
+ return PTR_ERR(lpwm);
+
+ pci_set_drvdata(pdev, lpwm);
+ return 0;
+}
+
+static void pwm_lpss_remove_pci(struct pci_dev *pdev)
+{
+ struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);
+
+ pwm_lpss_remove(lpwm);
+ pci_disable_device(pdev);
+}
+
+static struct pci_device_id pwm_lpss_pci_ids[] = {
+ { PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&byt_info},
+ { PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&byt_info},
+ { },
+};
+MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids);
+
+static struct pci_driver pwm_lpss_driver_pci = {
+ .name = "pwm-lpss",
+ .id_table = pwm_lpss_pci_ids,
+ .probe = pwm_lpss_probe_pci,
+ .remove = pwm_lpss_remove_pci,
+};
+
+static int pwm_lpss_probe_platform(struct platform_device *pdev)
+{
+ struct pwm_lpss_chip *lpwm;
+ struct resource *r;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ lpwm = pwm_lpss_probe(&pdev->dev, r, NULL);
+ if (IS_ERR(lpwm))
+ return PTR_ERR(lpwm);
+
+ platform_set_drvdata(pdev, lpwm);
+ return 0;
+}
+
+static int pwm_lpss_remove_platform(struct platform_device *pdev)
+{
+ struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
+
+ return pwm_lpss_remove(lpwm);
+}
+
+static const struct acpi_device_id pwm_lpss_acpi_match[] = {
+ { "80860F09", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
+
+static struct platform_driver pwm_lpss_driver_platform = {
.driver = {
.name = "pwm-lpss",
.acpi_match_table = pwm_lpss_acpi_match,
},
- .probe = pwm_lpss_probe,
- .remove = pwm_lpss_remove,
+ .probe = pwm_lpss_probe_platform,
+ .remove = pwm_lpss_remove_platform,
};
-module_platform_driver(pwm_lpss_driver);
+
+static int __init pwm_init(void)
+{
+ pci_drv = pci_register_driver(&pwm_lpss_driver_pci);
+ plat_drv = platform_driver_register(&pwm_lpss_driver_platform);
+ if (pci_drv && plat_drv)
+ return pci_drv;
+
+ return 0;
+}
+module_init(pwm_init);
+
+static void __exit pwm_exit(void)
+{
+ if (!pci_drv)
+ pci_unregister_driver(&pwm_lpss_driver_pci);
+ if (!plat_drv)
+ platform_driver_unregister(&pwm_lpss_driver_platform);
+}
+module_exit(pwm_exit);

MODULE_DESCRIPTION("PWM driver for Intel LPSS");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>");
--
1.7.4.4

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