releases/4.4.9/spi-rockchip-make-sure-spi-clk-is-on-in-rockchip_spi_set_cs.patch

   1 From b920cc3191d7612f26f36ee494e05b5ffd9044c0 Mon Sep 17 00:00:00 2001
   2 From: Huibin Hong <huibin.hong@rock-chips.com>
   3 Date: Wed, 24 Feb 2016 18:00:04 +0800
   4 Subject: spi/rockchip: Make sure spi clk is on in rockchip_spi_set_cs
   5
   6 From: Huibin Hong <huibin.hong@rock-chips.com>
   7
   8 commit b920cc3191d7612f26f36ee494e05b5ffd9044c0 upstream.
   9
  10 Rockchip_spi_set_cs could be called by spi_setup, but
  11 spi_setup may be called by device driver after runtime suspend.
  12 Then the spi clock is closed, rockchip_spi_set_cs may access the
  13 spi registers, which causes cpu block in some socs.
  14
  15 Fixes: 64e36824b32 ("spi/rockchip: add driver for Rockchip RK3xxx")
  16 Signed-off-by: Huibin Hong <huibin.hong@rock-chips.com>
  17 Signed-off-by: Mark Brown <broonie@kernel.org>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19
  20 ---
  21  drivers/spi/spi-rockchip.c |    7 ++++++-
  22  1 file changed, 6 insertions(+), 1 deletion(-)
  23
  24 --- a/drivers/spi/spi-rockchip.c
  25 +++ b/drivers/spi/spi-rockchip.c
  26 @@ -265,7 +265,10 @@ static inline u32 rx_max(struct rockchip
  27  static void rockchip_spi_set_cs(struct spi_device *spi, bool enable)
  28  {
  29         u32 ser;
  30 -       struct rockchip_spi *rs = spi_master_get_devdata(spi->master);
  31 +       struct spi_master *master = spi->master;
  32 +       struct rockchip_spi *rs = spi_master_get_devdata(master);
  33 +
  34 +       pm_runtime_get_sync(rs->dev);
  35
  36         ser = readl_relaxed(rs->regs + ROCKCHIP_SPI_SER) & SER_MASK;
  37
  38 @@ -290,6 +293,8 @@ static void rockchip_spi_set_cs(struct s
  39                 ser &= ~(1 << spi->chip_select);
  40
  41         writel_relaxed(ser, rs->regs + ROCKCHIP_SPI_SER);
  42 +
  43 +       pm_runtime_put_sync(rs->dev);
  44  }
  45
  46  static int rockchip_spi_prepare_message(struct spi_master *master,