Re: [PATCH 2/3] ASoC: OMAP4: Add support for McPDM

Candelaria Villareal, Jorge
2009-12-18T02:23:14Z

> -----Original Message-----
> From: Felipe Balbi [mailto:felipe.balbi@nokia.com]
> Sent: Thursday, December 17, 2009 2:28 PM
> To: Candelaria Villareal, Jorge
> Cc: alsa-devel@alsa-project.org; linux-omap@vger.kernel.org;
> broonie@opensource.wolfsonmicro.com
> Subject: Re: [PATCH 2/3] ASoC: OMAP4: Add support for McPDM
>
> Hi,
>
> On Thu, Dec 17, 2009 at 08:40:32PM +0100, ext Candelaria
> Villareal, Jorge wrote:
> >diff --git a/sound/soc/omap/Kconfig b/sound/soc/omap/Kconfig
> >index 61952aa..b96e9d8 100644
> >--- a/sound/soc/omap/Kconfig
> >+++ b/sound/soc/omap/Kconfig
> >@@ -6,6 +6,9 @@ config SND_OMAP_SOC_MCBSP
> > tristate
> > select OMAP_MCBSP
> >
> >+config SND_OMAP_SOC_MCPDM
> >+ tristate
>
> look at how SND_OMAP_SOC_N810 is done, can't you follow that
> ? put some
> description ad help ?

McPDM is only the interface between TWL6030 and OMAP. For the
SDP4430 board we will have another Kconfig entry which selects
SND_OMAP_SOC_MCPDM and adds a simple description. Adding: "Say
Y if you want to add support for McPDM interface" is probably
unnecesary.

>
> >diff --git a/sound/soc/omap/mcpdm.c b/sound/soc/omap/mcpdm.c
> >new file mode 100644
> >index 0000000..e162dd1
> >--- /dev/null
> >+++ b/sound/soc/omap/mcpdm.c
> >@@ -0,0 +1,505 @@
> >+/*
> >+ * mcpdm.c -- McPDM interface driver
> >+ *
> >+ * Author: Jorge Eduardo Candelaria <x0107209@ti.com>
>
> no copyright ? How about:
>
> Copyright (C) 2009 - Texas Instruments, Inc.
>
> >+ * 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 published by the Free Software Foundation.
> >+ *
> >+ * This program is distributed in the hope that it will be
> useful, but
> >+ * WITHOUT ANY WARRANTY; without even the implied warranty of
> >+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> >+ * General Public License for more details.
> >+ *
> >+ * You should have received a copy of the GNU General Public License
> >+ * along with this program; if not, write to the Free Software
> >+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> >+ * 02110-1301 USA
> >+ *
> >+ */
> >+
> >+#include <linux/module.h>
> >+#include <linux/init.h>
> >+#include <linux/device.h>
> >+#include <linux/platform_device.h>
> >+#include <linux/wait.h>
> >+#include <linux/interrupt.h>
> >+#include <linux/err.h>
> >+#include <linux/clk.h>
> >+#include <linux/delay.h>
> >+#include <linux/io.h>
> >+#include <linux/irq.h>
> >+
> >+#include "mcpdm.h"
>
> is this used by any other file ? If not, it shouldn't be necessary.

mcpdm.c exports its functions so that the cpu dai can configure
McPDM module according to the stream configuration.

Very similar to McBSP in OMAP3 but it is only used for audio.

>
> >+static struct omap_mcpdm *mcpdm;
>
> allocate on probe() and make it the private_data of the
> device structure
> with platform_set_drvdata(pdev, mcpdm);
>
> >+static void omap_mcpdm_write(u16 reg, u32 val)
>
> I'd rather:
>
> static inline void omap_mcpdm_write(struct omap_mcpdm *mcpdm,
> u16 reg, u32 val)
>

Yes, should be better to make it inline.

> >+{
> >+ __raw_writel(val, mcpdm->io_base + reg);
> >+}
> >+
> >+static int omap_mcpdm_read(u16 reg)
>
> ditto.
>
> >+{
> >+ return __raw_readl(mcpdm->io_base + reg);
> >+}
> >+
> >+void omap_mcpdm_reg_dump(void)
> >+{
> >+ dev_dbg(mcpdm->dev, "***********************\n");
> >+ dev_dbg(mcpdm->dev, "IRQSTATUS_RAW: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_IRQSTATUS_RAW));
> >+ dev_dbg(mcpdm->dev, "IRQSTATUS: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_IRQSTATUS));
> >+ dev_dbg(mcpdm->dev, "IRQENABLE_SET: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_IRQENABLE_SET));
> >+ dev_dbg(mcpdm->dev, "IRQENABLE_CLR: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_IRQENABLE_CLR));
> >+ dev_dbg(mcpdm->dev, "IRQWAKE_EN: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_IRQWAKE_EN));
> >+ dev_dbg(mcpdm->dev, "DMAENABLE_SET: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_DMAENABLE_SET));
> >+ dev_dbg(mcpdm->dev, "DMAENABLE_CLR: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_DMAENABLE_CLR));
> >+ dev_dbg(mcpdm->dev, "DMAWAKEEN: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_DMAWAKEEN));
> >+ dev_dbg(mcpdm->dev, "CTRL: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_CTRL));
> >+ dev_dbg(mcpdm->dev, "DN_DATA: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_DN_DATA));
> >+ dev_dbg(mcpdm->dev, "UP_DATA: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_UP_DATA));
> >+ dev_dbg(mcpdm->dev, "FIFO_CTRL_DN: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_FIFO_CTRL_DN));
> >+ dev_dbg(mcpdm->dev, "FIFO_CTRL_UP: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_FIFO_CTRL_UP));
> >+ dev_dbg(mcpdm->dev, "DN_OFFSET: 0x%04x\n",
> >+ omap_mcpdm_read(MCPDM_DN_OFFSET));
> >+ dev_dbg(mcpdm->dev, "***********************\n");
> >+}
> >+EXPORT_SYMBOL(omap_mcpdm_reg_dump);
>
> I'd rather use debugfs for such stuff.

Ok

>
> >+EXPORT_SYMBOL(omap_mcpdm_set_offset);
> >+EXPORT_SYMBOL(omap_mcpdm_reset);
> >+EXPORT_SYMBOL(omap_mcpdm_start);
> >+EXPORT_SYMBOL(omap_mcpdm_stop);
> >+EXPORT_SYMBOL(omap_mcpdm_set_uplink);
> >+EXPORT_SYMBOL(omap_mcpdm_set_downlink);
> >+EXPORT_SYMBOL(omap_mcpdm_clr_uplink);
> >+EXPORT_SYMBOL(omap_mcpdm_clr_downlink);
> >+EXPORT_SYMBOL(omap_mcpdm_request);
> >+EXPORT_SYMBOL(omap_mcpdm_free);
>
> way too many exported symbols, no ? Doesn't ALSA API have
> proper place
> for this kind of stuff ? I'd need ALSA experts to reply to
> that but it
> does smell funny...

As I said, this functions are used by the cpu dai to configure
the McPDM interface. Another approach would be to get rid of mcpdm.c
and have the cpu dai directly modify McPDM registers.

It still seems better to separate ALSA from the McPDM driver like
this. Comments from ALSA guys on this would be good.

>
> >+static irqreturn_t omap_mcpdm_irq_handler(int irq, void *dev_id)
> >+{
> >+ struct omap_mcpdm *mcpdm_irq = dev_id;
> >+ int irq_status;
> >+
> >+ irq_status = omap_mcpdm_read(MCPDM_IRQSTATUS);
> >+
> >+ /* Acknowledge irq event */
> >+ omap_mcpdm_write(MCPDM_IRQSTATUS, irq_status);
> >+
> >+ switch (irq_status) {
>
> it's better if you:
>
> if (irq_status & DN_IRQ_FULL) {
> ...
> }
>
> if (irq_status & DN_IRQ_EMPTY) {
> ...
> }
>
> if (irq_status & DN_IRQ) {
> ...
> }

Is this because if two interrupts were set, my approach would
not recognize it as one of the cases and exit without processing
the interrupt?

>
> >+int omap_mcpdm_request(void)
> >+{
> >+ int ret;
> >+
> >+ clk_enable(mcpdm->clk);
> >+
> >+ spin_lock(&mcpdm->lock);
> >+
> >+ if (!mcpdm->free) {
> >+ dev_err(mcpdm->dev, "McPDM interface is in use\n");
> >+ spin_unlock(&mcpdm->lock);
> >+ return -EBUSY;
> >+ }
> >+ mcpdm->free = 0;
> >+
> >+ spin_unlock(&mcpdm->lock);
> >+
> >+ /* Disable lines while request is ongoing */
> >+ omap_mcpdm_write(MCPDM_CTRL, 0x00);
> >+
> >+ ret = request_irq(mcpdm->irq, omap_mcpdm_irq_handler,
> >+ 0, "McPDM", (void *)mcpdm);
> >+ if (ret) {
> >+ dev_err(mcpdm->dev, "Request for McPDM IRQ
> failed\n");
> >+ return ret;
> >+ }
> >+
> >+ return 0;
> >+}
> >+EXPORT_SYMBOL(omap_mcpdm_request);
>
> How about moving this to probe() ??

The idea is to call request resources only when needed by the cpu
dai. It is done in a similar manner in McBSP driver.

>
> >+void omap_mcpdm_free(void)
> >+{
> >+ clk_disable(mcpdm->clk);
> >+
> >+ spin_lock(&mcpdm->lock);
> >+ if (mcpdm->free) {
> >+ dev_err(mcpdm->dev, "McPDM interface is
> already free\n");
> >+ spin_unlock(&mcpdm->lock);
> >+ return;
> >+ }
> >+ mcpdm->free = 1;
> >+ spin_unlock(&mcpdm->lock);
> >+
> >+ free_irq(mcpdm->irq, (void *)mcpdm);
> >+}
> >+EXPORT_SYMBOL(omap_mcpdm_free);
>
> move to remove()

Same here...

>
> >+static int __devinit omap_mcpdm_probe(struct platform_device *pdev)
> >+{
> >+ struct omap_mcpdm_platform_data *pdata =
> pdev->dev.platform_data;
> >+ int ret = 0;
> >+
> >+ if (!pdata) {
> >+ dev_err(&pdev->dev, "McPDM device
> initialized without "
> >+ "platform data\n");
>
> try not to break the string, it makes grep much more
> difficult. You can
> also make a smaller string like: "no platform data" or something...

I will change this to something smaller.

>
> >+ ret = -EINVAL;
> >+ goto exit;
> >+ }
> >+ dev_dbg(&pdev->dev, "Initializing OMAP McPDM driver \n");
>
> not needed this message.
>
> >+ mcpdm = kzalloc(sizeof(struct omap_mcpdm), GFP_KERNEL);
> >+ if (!mcpdm) {
> >+ ret = -ENOMEM;
> >+ goto exit;
> >+ }
> >+
> >+ spin_lock_init(&mcpdm->lock);
> >+ mcpdm->free = 1;
> >+ mcpdm->phys_base = pdata->phys_base;
>
> this is passed via struct resource.
>
> >+ mcpdm->io_base = ioremap(mcpdm->phys_base, SZ_4K);
>
> then this would be something like:
>
> static int __devinit omap_mcpdm_probe(struct platform_device *pdev)
> {
> ...
> struct resource *res;
> ...
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> if (res == NULL) {
> dev_err(&pdev->dev, "no resource\n");
> goto err1;
> }
>
> mcpdm->io_base = ioremap(res->start, resource_size(res));
> if (mcpdm->io_base == NULL) {
> dev_err(&pdev->dev, "ioremap failed\n");
> goto err2;
> }
>
> ...
>
> >+ if (!mcpdm->io_base) {
> >+ ret = -ENOMEM;
> >+ goto err_ioremap;
> >+ }
> >+
> >+ mcpdm->irq = pdata->irq;
> >+
> >+ /* FIXME: Enable this ones correct clk nodes available */
> >+ if (!cpu_is_omap44xx()) {
>
> if you don't use the code now, don't add it.
>
> >+ mcpdm->clk = clk_get(&pdev->dev, "fclk");
> >+ if (IS_ERR(mcpdm->clk)) {
> >+ ret = PTR_ERR(mcpdm->clk);
> >+ dev_err(&pdev->dev, "unable to get
> fclk: %d\n", ret);
> >+ goto err_clk;
> >+ }
> >+ }
> >+
> >+ mcpdm->pdata = pdata;
>
> pdata is supposed to be __initdata, no point in saving it.
>
> >+ mcpdm->dev = &pdev->dev;
> >+ platform_set_drvdata(pdev, mcpdm);
> >+
> >+ return 0;
> >+
> >+err_clk:
> >+ iounmap(mcpdm->io_base);
> >+err_ioremap:
> >+ kfree(mcpdm);
> >+exit:
> >+ return ret;
> >+}
> >+
> >+static int __devexit omap_mcpdm_remove(struct platform_device *pdev)
> >+{
> >+ struct omap_mcpdm *mcpdm_ptr = platform_get_drvdata(pdev);
> >+
> >+ platform_set_drvdata(pdev, NULL);
> >+
> >+ if (mcpdm_ptr) {
>
> if this pointer is NULL, the you deserve to oops, get rid of
> the branch.
>
> >+ clk_disable(mcpdm_ptr->clk);
> >+ clk_put(mcpdm_ptr->clk);
> >+
> >+ iounmap(mcpdm_ptr->io_base);
> >+
> >+ mcpdm_ptr->clk = NULL;
> >+ mcpdm_ptr->free = 0;
> >+ mcpdm_ptr->dev = NULL;
>
> where's your kfree(mcpdm_ptr) ???
>
> >+ printk(KERN_INFO "McPDM driver removed \n");
>
> get rid of this.
>
> >+static struct platform_driver omap_mcpdm_driver = {
> >+ .probe = omap_mcpdm_probe,
> >+ .remove = omap_mcpdm_remove,
>
> .remove = __devexit_p(omap_mcpdm_remove),
>
> >+ .driver = {
> >+ .name = "omap-mcpdm",
> >+ },
> >+};
> >+
> >+static struct platform_device *omap_mcpdm_device;
> >+
> >+static struct omap_mcpdm_platform_data mcpdm_pdata = {
> >+ .phys_base = OMAP44XX_MCPDM_BASE,
> >+ .irq = INT_44XX_MCPDM_IRQ,
> >+};
>
> this should be passed by arch code, no ??
>
> >+static int __init omap_mcpdm_init(void)
> >+{
> >+ int ret;
> >+ struct platform_device *device;
> >+
> >+ device = platform_device_alloc("omap-mcpdm", -1);
> >+ if (!device) {
> >+ printk(KERN_ERR "McPDM platform device
> allocation failed\n");
> >+ return -ENOMEM;
> >+ }
> >+ device->dev.platform_data = &mcpdm_pdata;
>
> although n810 does the same, I don't like it. I think the board file
> should register the platform_device
>
> >+ omap_mcpdm_device = device;
> >+ (void) platform_device_add(omap_mcpdm_device);
>
> what ? so even if you don't have a platform_device you register the
> driver ??

So, it would be better if I had declared a platform_device structure
in .../arch/arm/plat-omap/devices.c, and register its resources (irq
and memory base) in there?

>
> >+ ret = platform_driver_register(&omap_mcpdm_driver);
> >+ if (ret)
> >+ goto error;
> >+ return 0;
> >+
> >+error:
> >+ printk(KERN_ERR "OMAP McPDM initialization error\n");
>
> no printk(), simply return err.
>
> >+ return ret;
> >+}
> >+arch_initcall(omap_mcpdm_init);
>
> I wonder if arch_initcall() is really necessary...
>
> >diff --git a/sound/soc/omap/mcpdm.h b/sound/soc/omap/mcpdm.h
> >new file mode 100644
> >index 0000000..c953e95
> >--- /dev/null
> >+++ b/sound/soc/omap/mcpdm.h
> >@@ -0,0 +1,156 @@
> >+/*
> >+ * mcpdm.h -- Defines for McPDM driver
> >+ *
> >+ * Author: Jorge Eduardo Candelaria <x0107209@ti.com>
> >+ *
> >+ * 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 published by the Free Software Foundation.
> >+ *
> >+ * This program is distributed in the hope that it will be
> useful, but
> >+ * WITHOUT ANY WARRANTY; without even the implied warranty of
> >+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> >+ * General Public License for more details.
> >+ *
> >+ * You should have received a copy of the GNU General Public License
> >+ * along with this program; if not, write to the Free Software
> >+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> >+ * 02110-1301 USA
> >+ *
> >+ */
> >+
> >+#define OMAP44XX_MCPDM_BASE 0x40132000
> >+#define OMAP44XX_MCPDM_L3_BASE 0x49032000
>
> not here... probably in some <plat/cpu.h> or similar...

Yes, probably <plat/omap44xx.h>...

>
> >+/* McPDM registers */
> >+
> >+#define MCPDM_REVISION 0x00
> >+#define MCPDM_SYSCONFIG 0x10
> >+#define MCPDM_IRQSTATUS_RAW 0x24
> >+#define MCPDM_IRQSTATUS 0x28
> >+#define MCPDM_IRQENABLE_SET 0x2C
> >+#define MCPDM_IRQENABLE_CLR 0x30
> >+#define MCPDM_IRQWAKE_EN 0x34
> >+#define MCPDM_DMAENABLE_SET 0x38
> >+#define MCPDM_DMAENABLE_CLR 0x3C
> >+#define MCPDM_DMAWAKEEN 0x40
> >+#define MCPDM_CTRL 0x44
> >+#define MCPDM_DN_DATA 0x48
> >+#define MCPDM_UP_DATA 0x4C
> >+#define MCPDM_FIFO_CTRL_DN 0x50
> >+#define MCPDM_FIFO_CTRL_UP 0x54
> >+#define MCPDM_DN_OFFSET 0x58
> >+
> >+/*
> >+ * MCPDM_IRQ bit fields
> >+ * IRQSTATUS_RAW, IRQSTATUS, IRQENABLE_SET, IRQENABLE_CLR
> >+ */
> >+
> >+#define DN_IRQ (1 << 0)
> >+#define DN_IRQ_EMTPY (1 << 1)
> >+#define DN_IRQ_ALMST_EMPTY (1 << 2)
> >+#define DN_IRQ_FULL (1 << 3)
> >
> >+#define UP_IRQ (1 << 8)
> >+#define UP_IRQ_EMPTY (1 << 9)
> >+#define UP_IRQ_ALMST_FULL (1 << 10)
> >+#define UP_IRQ_FULL (1 << 11)
> >+
> >+#define DOWNLINK_IRQ_MASK 0x00F
> >+#define UPLINK_IRQ_MASK 0xF00
>
> prepend with MCPDM_
>
> >+void omap_mcpdm_reg_dump(void);
> >+void omap_mcpdm_reset(int links, int reset);
> >+void omap_mcpdm_start(int stream);
> >+void omap_mcpdm_stop(int stream);
> >+int omap_mcpdm_set_uplink(struct omap_mcpdm_link *uplink);
> >+int omap_mcpdm_set_downlink(struct omap_mcpdm_link *downlink);
> >+int omap_mcpdm_clr_uplink(struct omap_mcpdm_link *uplink);
> >+int omap_mcpdm_clr_downlink(struct omap_mcpdm_link *downlink);
> >+int omap_mcpdm_request(void);
> >+void omap_mcpdm_free(void);
> >+int omap_mcpdm_set_offset(int offset1, int offset2);
>
> these shouldn't be necessary but at least the extern is missing.
>
> --
> balbi
>