467265eeb44ba70dfb18d27256a69eb8d5c57e49
[glsdk/meta-ti-glsdk.git] / recipes-bsp / linux / linux-omap / linus / 0028-spi-omap2_mcspi.c-Force-CS-to-be-in-inactive-state-a.patch
1 From 42ce7fd6319bed8ecb26d656c476365da46b29e9 Mon Sep 17 00:00:00 2001
2 From: Gregory CLEMENT <gregory.clement@free-electrons.com>
3 Date: Wed, 29 Dec 2010 11:52:53 +0100
4 Subject: [PATCH 28/66] spi/omap2_mcspi.c: Force CS to be in inactive state after off-mode transition
6 When SPI wake up from OFF mode, CS is in the wrong state: force it to the
7 inactive state.
9 During the system life, I monitored the CS behavior using a oscilloscope.
10 I also activated debug in omap2_mcspi, so I saw when driver disable the clocks
11 and restore context when device is not used.Each time the CS was in the correct
12 state. It was only when system was put suspend to ram with off-mode activated
13 that on resume the CS was in wrong state( ie activated).
15 Changelog:
16 * Change from v1 to v2:
17 - Rebase on linus/master (after 2.6.37-rc1)
18 - Do some clean-up and fix indentation on both patches
19 - Add more explanations for patch 2
21 * Change from v2 to v3:
22 - Use directly resume function of spi_master instead of using function
23 - from spi_device as Grant Likely pointed it out.
24 - Force this transition explicitly for each CS used by a device.
26 * Change from v3 to v4:
27 - Patch clean-up according to Kevin Hilman and checkpatch.
28 - Now force CS to be in inactive state only if it was inactive when it was
29 suspended.
31 * Change from v4 to v5:
32 - Rebase on linus/master (after 2.6.37-rc3)
33 - Collapse some lines as pointed by Grant Likely
34 - Fix a spelling
36 * Change from v5 to v6:
37 - Rebase on linus/master (after 2.6.37-rc7)
38 - Use CONFIG_SUSPEND instead of CONFIG_PM
39 - Didn't use legacy PM methods anymore. Instead, add a struct dev_pm_ops and
40 add the resume method there.
41 - Fix multi-line comment style
43 * Change from v6 to v7:
44 - Rebase on linus/master (after 2.6.37-rc8)
45 - Drop an extra line
47 Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
48 Acked-by: David Brownell <dbrownell@users.sourceforge.net>
49 Reviewed-by: Kevin Hilman <khilman@deeprootsystems.com>
50 Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
51 ---
52 drivers/spi/omap2_mcspi.c | 39 +++++++++++++++++++++++++++++++++++++++
53 1 files changed, 39 insertions(+), 0 deletions(-)
55 diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
56 index 2a651e6..951a160 100644
57 --- a/drivers/spi/omap2_mcspi.c
58 +++ b/drivers/spi/omap2_mcspi.c
59 @@ -1305,10 +1305,49 @@ static int __exit omap2_mcspi_remove(struct platform_device *pdev)
60 /* work with hotplug and coldplug */
61 MODULE_ALIAS("platform:omap2_mcspi");
63 +#ifdef CONFIG_SUSPEND
64 +/*
65 + * When SPI wake up from off-mode, CS is in activate state. If it was in
66 + * unactive state when driver was suspend, then force it to unactive state at
67 + * wake up.
68 + */
69 +static int omap2_mcspi_resume(struct device *dev)
70 +{
71 + struct spi_master *master = dev_get_drvdata(dev);
72 + struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
73 + struct omap2_mcspi_cs *cs;
74 +
75 + omap2_mcspi_enable_clocks(mcspi);
76 + list_for_each_entry(cs, &omap2_mcspi_ctx[master->bus_num - 1].cs,
77 + node) {
78 + if ((cs->chconf0 & OMAP2_MCSPI_CHCONF_FORCE) == 0) {
79 +
80 + /*
81 + * We need to toggle CS state for OMAP take this
82 + * change in account.
83 + */
84 + MOD_REG_BIT(cs->chconf0, OMAP2_MCSPI_CHCONF_FORCE, 1);
85 + __raw_writel(cs->chconf0, cs->base + OMAP2_MCSPI_CHCONF0);
86 + MOD_REG_BIT(cs->chconf0, OMAP2_MCSPI_CHCONF_FORCE, 0);
87 + __raw_writel(cs->chconf0, cs->base + OMAP2_MCSPI_CHCONF0);
88 + }
89 + }
90 + omap2_mcspi_disable_clocks(mcspi);
91 + return 0;
92 +}
93 +#else
94 +#define omap2_mcspi_resume NULL
95 +#endif
96 +
97 +static const struct dev_pm_ops omap2_mcspi_pm_ops = {
98 + .resume = omap2_mcspi_resume,
99 +};
100 +
101 static struct platform_driver omap2_mcspi_driver = {
102 .driver = {
103 .name = "omap2_mcspi",
104 .owner = THIS_MODULE,
105 + .pm = &omap2_mcspi_pm_ops
106 },
107 .remove = __exit_p(omap2_mcspi_remove),
108 };
109 --
110 1.6.6.1